


        HOME AND AWAY CREDIT CARD ADAPTER

        AT COMMANDS

































































































































        HOME AND AWAY CREDIT CARD ADAPTER

        AT COMMANDS






















































        IBM























  FIRST EDITION (JUNE 1995)

  THE FOLLOWING PARAGRAPH DOES NOT APPLY TO THE UNITED KINGDOM OR ANY
  COUNTRY WHERE SUCH PROVISIONS ARE INCONSISTENT WITH LOCAL
  LAW:  INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS
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  IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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  not allow disclaimer of express or implied warranties in certain
  transactions, therefore, this statement may not apply to you.

  This publication could include technical inaccuracies or typographical
  errors.  Changes are periodically made to the information herein;
  these changes will be incorporated in new editions of the publication.
  IBM may make improvements and/or changes in the products and/or
  programs described in this publication at any time.

  It is possible that this publication may contain reference to, or
  information about, IBM products (machines and programs), programming,
  or services that are not announced in your country.  Such references
  or information must not be construed to mean that IBM intends to
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  When you send information to IBM, you grant IBM a nonexclusive right
  to use or distribute the information in any way it believes
  appropriate without incurring any obligation to you.

  (C) COPYRIGHT INTERNATIONAL BUSINESS MACHINES CORPORATION 1995.  ALL
  RIGHTS RESERVED.
  Note to U.S. Government Users -- Documentation related to restricted
  rights -- Use, duplication or disclosure is subject to restrictions
  set forth in GSA ADP Schedule Contract with IBM Corp.









  CONTENTS
  ________





                      CHAPTER 1.  ADVANCED CONTROL SETTINGS  . . . . . . . .  1
                      The AT Command Set   . . . . . . . . . . . . . . . . .  1
                      AT Command Table   . . . . . . . . . . . . . . . . . .  4
                      Basic AT Commands  . . . . . . . . . . . . . . . . . .  6
                      Serial Port Control  . . . . . . . . . . . . . . . .   17
                      Extended AT Commands   . . . . . . . . . . . . . . .   19

                      CHAPTER 2.  S-REGISTERS  . . . . . . . . . . . . . .   29
                      Reading a Register Value   . . . . . . . . . . . . .   30
                      How to Set Bit-Mapped Registers  . . . . . . . . . .   30
                      Changing a Register Value  . . . . . . . . . . . . .   31
                      Accessing a Register Repeatedly  . . . . . . . . . .   31
                      S-Register Descriptions  . . . . . . . . . . . . . .   32
                      S-Register Table   . . . . . . . . . . . . . . . . .   33

                      CHAPTER 3.  MNP OPERATION  . . . . . . . . . . . . .   53
                      MNP Data Mode  . . . . . . . . . . . . . . . . . . .   54
                      MNP5 Data Compression  . . . . . . . . . . . . . . .   55
                      Programmable Inactivity Timer  . . . . . . . . . . .   55
                      Data Transfer  . . . . . . . . . . . . . . . . . . .   55
                      AT Commands for MNP Operation  . . . . . . . . . . .   55

                      CHAPTER 4.  THE ITU-T STANDARD   . . . . . . . . . .   61
                      V.32 and V.32bis Operation   . . . . . . . . . . . .   61
                      V.42 and V.42bis Error Correction  . . . . . . . . .   62
                      AT Commands for V.42   . . . . . . . . . . . . . . .   63

                      CHAPTER 5.  CELLULAR COMMANDS  . . . . . . . . . . .   65






















  (C) Copyright IBM Corp. 1995                                              iii

































































  iv  AT Commands









  CHAPTER 1.  ADVANCED CONTROL SETTINGS
  _____________________________________





                      This manual provides information on using the AT command
                      set for modem control.


  THE AT COMMAND SET
  __________________

                      The modem supports the standard and extended Hayes AT
                      command set.  "AT" characters are called the attention
                      code.  These commands are the industry-standard language
                      used to communicate with the modem.  To use these
                      commands, load your communications program and enter into
                      command mode.

                      Your communications package can send "AT" commands to
                      your modem from the configuration and setup modes.

                      The modem is always in one of three modes:  command mode,
                      fax mode, or data mode.  The modem enters command mode
                      when it is turned on or reset, when it loses a connection
                      with a remote modem, or when it is in online mode and you
                      type certain escape characters.

                      When the modem is in command mode, it accepts
                      instructions in the form of commands and it returns
                      responses.  This mode allows the modem to be configured
                      for a particular application or instructed to perform a
                      function.  These settings will remain active until the
                      computer is turned off.  The modem then returns to its
                      default settings.  Through your communications program,
                      you can set up a configuration file that reconfigures
                      your modem every time you run the software.  The modem
                      enters data mode when it has made a connection with a
                      remote modem and sends the connection response confirming
                      the connection has been established.  Data can then be
                      exchanged.

                      The specific command rules are:

                      o   Commands must begin with the "AT" prefix.

                      o   Characters must be in all uppercase or all lowercase.

                      o   Commands can contain up to 40 characters.

                      o   Space characters in the commands are ignored.

                      o   Commands are sent to the modem only when you press
                          ENTER.


  (C) Copyright IBM Corp. 1995                                                1









                      o   Multiple commands can appear on a single line.

                      o   Backspace over typing errors to correct them before
                          pressing the Enter key.

                      Use the "AT&V" command to display the active
                      configuration and stored user profiles.


  ONLINE STATE

                      To transmit or receive data, the modem must be in the
                      online state.  When placing a call, the modem is put
                      online with the dial command.  At the remote end, the
                      modem goes online when it is instructed to answer a call
                      automatically by setting the register S0 equal to any
                      number greater than 0 and less than 255.  You can also
                      perform this function with the "ATA" command.


  ESCAPE SEQUENCE

                      After a connection has been established with a remote
                      modem, you can return to command mode without breaking
                      that connection by typing the escape sequence.  The
                      escape sequence consists of three characters ("+++").  It
                      is not necessary to begin this sequence with the "AT"
                      attention code, or by pressing ENTER after typing the
                      escape code.


  RETURN TO ONLINE STATE

                      The modem can be returned to the online state after the
                      escape sequence has been issued.  To return the modem to
                      the online state, issue the "ATO" command.  To return the
                      modem online and then initiate an equalizer retrain
                      sequence, use the "ATO1" command.


  RERUNNING THE LAST COMMAND

                      Each command sent to the modem remains in the command
                      buffer until the next "AT" command is sent or until power
                      to the modem is turned off.  To repeat the last command
                      issued, type the command "A/".  The A/ command is not
                      preceded by the "AT" characters or followed by pressing
                      ENTER.








  2  AT Commands









  OMITTING A PARAMETER

                      Some commands require a parameter to completely define
                      them.  If a parameter is omitted from a command that
                      requires one, the command will respond with the default
                      value.


  RESULT CODES

                      A response is displayed on your screen by the modem,
                      indicating the result after it processes, or tries to
                      process, a command.  These result codes display the
                      status of the modem or the progress of a call, and can
                      take the form of either words (for example, "OK" after
                      you input an "AT" command) or digits.  The default
                      consists of word responses that are defined with the "V1"
                      command.  To receive digit responses rather than word
                      responses, use the "V0" command.  To disable the
                      responses entirely, use the "Q1" command.




































                                       Chapter 1.  Advanced Control Settings  3









  AT COMMAND TABLE
  ________________

                      The tables on the following pages list the AT commands,
                      their description and provides the page number where the
                      discussion of available parameters can be found.

                      +-------------------------------------------------------+
                      | Table 1 (Page 1 of 3). AT Command Set page references |
                      +----------+---------------------------------------+----+
                      |    AT    | DESCRIPTION                           | PAG|
                      |  COMMAND |                                       |    |
                      +----------+---------------------------------------+----+
                      |     A    | Answer command                        |  6 |
                      +----------+---------------------------------------+----+
                      |    Bn    | Select communication standard         |  7 |
                            _
                      +----------+---------------------------------------+----+
                      |    Dn    | Dial                                  |  8 |
                            _
                      +----------+---------------------------------------+----+
                      |    En    | Echo back command characters          |  9 |
                            _
                      +----------+---------------------------------------+----+
                      |    Fn    | Select Line Modulation                |  9 |
                            _
                      +----------+---------------------------------------+----+
                      |    Hn    | Switch hook control                   | 10 |
                            _
                      +----------+---------------------------------------+----+
                      |    In    | Identification                        | 10 |
                            _
                      +----------+---------------------------------------+----+
                      |    Ln    | Speaker volume                        | 10 |
                            _
                      +----------+---------------------------------------+----+
                      |    Mn    | Speaker control                       | 11 |
                            _
                      +----------+---------------------------------------+----+
                      |    Nn    | Automode enable                       | 11 |
                            _
                      +----------+---------------------------------------+----+
                      |    On    | Return to online state mode           | 11 |
                            _
                      +----------+---------------------------------------+----+
                      |    Pn    | Pulse Dial as the Default             | 11 |
                            _
                      +----------+---------------------------------------+----+
                      |    Qn    | Modem responses enabled or disabled   | 12 |
                            _
                      +----------+---------------------------------------+----+
                      |     S    | S-register set                        | 29 |
                      +----------+---------------------------------------+----+
                      |     T    | Tone Dial as the Default              | 12 |
                      +----------+---------------------------------------+----+
                      |    Vn    | Result-code format                    | 12 |
                            _
                      +----------+---------------------------------------+----+
                      |    Wn    | Negotiation progress messages         | 12 |
                            _
                      +----------+---------------------------------------+----+
                      |    Xn    | Extend response codes                 | 13 |
                            _
                      +----------+---------------------------------------+----+
                      |    Yn    | Control long-space disconnect         | 18 |
                            _
                      +----------+---------------------------------------+----+
                      |    Zn    | Reset the modem and restore profile   | 18 |
                            _
                      +----------+---------------------------------------+----+
                      |    &Cn   | Data carrier detect (DCD) signal      | 19 |
                             _
                      +----------+---------------------------------------+----+


  4  AT Commands









                      +-------------------------------------------------------+
                      | Table 1 (Page 2 of 3). AT Command Set page references |
                      +----------+---------------------------------------+----+
                      |    AT    | DESCRIPTION                           | PAG|
                      |  COMMAND |                                       |    |
                      +----------+---------------------------------------+----+
                      |    &Dn   | Data terminal ready (DTR) signal      | 19 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Fn   | Recall factory defaults               | 20 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Gn   | Guard tone select (ITU-T mode)        | 20 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Kn   | DTE/modem flow control                | 21 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Mn   | Mode selection                        | 21 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Pn   | Select pulse dial make/break ratio    | 22 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Qn   | Synchronous/asynchronous mode         | 22 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Rn   | RTS/CTS option                        | 22 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Sn   | Data set ready (DSR) signal           | 23 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Tn   | Test and diagnostics                  | 23 |
                             _
                      +----------+---------------------------------------+----+
                      |    &V    | View current settings                 | 23 |
                      +----------+---------------------------------------+----+
                      |    &Wn   | Store user profile                    | 25 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Xn   | Select clock source                   | 25 |
                             _
                      +----------+---------------------------------------+----+
                      |    &Yn   | Designate default user profile        | 25 |
                             _
                      +----------+---------------------------------------+----+
                      |   &Zn=x  | Store phone number                    | 25 |
                            _ _
                      +----------+---------------------------------------+----+
                      |    )Mn   | Enable Cellular Power-Level           | 26 |
                             _
                      |          | Adjustment                            |    |
                      +----------+---------------------------------------+----+
                      |    -Kn   | MNP Extended Services                 | 26 |
                             _
                      +----------+---------------------------------------+----+
                      |    -Qn   | Enable Fallback to V.22/V.22bis       | 27 |
                             _
                      +----------+---------------------------------------+----+
                      |    *Hn   | Link Negotiation Speed                | 27 |
                             _
                      +----------+---------------------------------------+----+
                      |    %Cn   | Enable/disable V.42 data compression  | 63 |
                             _
                      +----------+---------------------------------------+----+
                      |    %En   | Enable/disable V.42 quality monitor   | 63 |
                             _
                      |          | automatic training                    |    |
                      +----------+---------------------------------------+----+
                      |    %Q    | Report V.42 line signal quality       | 63 |
                      +----------+---------------------------------------+----+
                      |    \An   | Maximum MNP block size                | 56 |
                             _
                      +----------+---------------------------------------+----+


                                       Chapter 1.  Advanced Control Settings  5









                      +-------------------------------------------------------+
                      | Table 1 (Page 3 of 3). AT Command Set page references |
                      +----------+---------------------------------------+----+
                      |    AT    | DESCRIPTION                           | PAG|
                      |  COMMAND |                                       |    |
                      +----------+---------------------------------------+----+
                      |    \Bn   | MNP Transmit break                    | 56 |
                             _
                      +----------+---------------------------------------+----+
                      |    \Gn   | MNP Modem-to-modem flow control       | 56 |
                             _
                      +----------+---------------------------------------+----+
                      |    \Kn   | MNP Break control                     | 56 |
                             _
                      +----------+---------------------------------------+----+
                      |    \Ln   | MNP block transfer control            | 58 |
                             _
                      +----------+---------------------------------------+----+
                      |    \Nn   | MNP Error correction operating mode   | 58 |
                             _
                      +----------+---------------------------------------+----+
                      |  +FAE=n  | Data/Fax Auto Answer                  | 58 |
                              _
                      +----------+---------------------------------------+----+
                      | +FCLASSn=| Set Class Service                     | 59 |
                               _ _
                      +----------+---------------------------------------+----+
                      | +<COMMAND|?Query Current Service Class           | 59 |
                      +----------+---------------------------------------+----+
                      | +<COMMAND|=Identify Fax Service Capability       | 59 |
                      +----------+---------------------------------------+----+
                      | &caret.C2| Download Cellular Phone Driver        | 65 |
                      +----------+---------------------------------------+----+
                      | &caret.I | Identify Cellular Phone Driver        | 65 |
                      +----------+---------------------------------------+----+
                      | &caret.T6| Indicate Status of Cellular Phone     | 66 |
                      +----------+---------------------------------------+----+


  BASIC AT COMMANDS
  _________________

                      The following lists the basic AT commands and their
                      functions.  Default settings are indicated where
                      applicable.

                      COMMAND   DESCRIPTION

                      A         ANSWER COMMAND
                                The modem will go off the hook, transmit the
                                answer tone, and wait for a carrier from the
                                remote modem.

                                Syntax:  "ATA"  ENTER










  6  AT Commands









                      Bn        SELECT COMMUNICATIONS STANDARD
                       _

                                Syntax:  "ATB"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects V.22 2100 Hz answer tone at
                                _
                                         1200 bps.
                                n=1      Selects Bell (00) 212A 2225 Hz answer
                                _
                                         tone at 1200 bps (default).















































                                       Chapter 1.  Advanced Control Settings  7









                      Dn        DIAL
                       _
                                This command directs the modem to go on-line,
                                dial according to the string entered and
                                attempt to establish a connection.  If no dial
                                string is supplied, the modem will go on-line
                                and attempt the handshake in originate mode.
                                NOTE: If the ATD command is issued before the
                                S1 register has cleared, the modem will respond
                                with the NO CARRIER result code.
                                The valid dial string parameters are described
                                below.  Punctuation characters may be used for
                                clarity, with parentheses, hyphen, and spaces
                                being ignored.

                                Syntax:  "ATD"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0-9    DTMF digits 0 to 9.
                                _
                                n=*      The 'star' digit (tone dialing only).
                                _
                                n=#      The 'gate' digit (tone dialing only).
                                _
                                n=A-D    DTMF digits A, B, C, and D.
                                _
                                n=J      Perform MNP 10 link negotiation at
                                _
                                         1200 bps (for this call only).
                                n=K      Enable power level adjustment during
                                _
                                         MNP 10 link negotiation (for this call
                                         only).
                                n=L      Re-dial last number; the L must be
                                _
                                         immediately after the D with all the
                                         following characters ignored.
                                n=P      Select pulse dialing; pulse dial the
                                _
                                         numbers that follow until a T is
                                         encountered.
                                n=T      Select tone dialing; tone dial the
                                _
                                         numbers that follow until a P is
                                         encountered.
                                n=R      This command will be accepted, but not
                                _
                                         acted on.
                                n=S=N    Dial the number stored in the
                                _
                                         directory.
                                n=!      Flash; the modem will go on-hook for a
                                _
                                         time defined by the value of S29.
                                n=W      Wait for dial tone; the modem will
                                _
                                         wait for dial tone before dialing the
                                         digits following W.












  8  AT Commands









                                n=@      Wait for silence; the modem will wait
                                _
                                         for at least 5 seconds of silence in
                                         the call progress frequency band
                                         before continuing with the next dial
                                         string parameter.
                                n=&      Wait for AT&T tone for credit card
                                _
                                         dialing before continuing with dial
                                         string.
                                n=,      Dial pause; the modem will pause for a
                                _
                                         time specified by S8 before dialing
                                         the digits.
                                n=;      Return to command state.
                                _
                                n=&HAT.  Toggles calling tone enable/disable.
                                _
                                n=()     Ignored.
                                _
                                n=-      Ignored.
                                _
                                n=<SPACE> Ignored.
                                _
                                n=<I>    Incorrect character; will be ignored.
                                _


                      En        ECHO BACK COMMAND CHARACTERS
                       _

                                Syntax:  "ATE"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disables the echoing of commands to
                                _
                                         the screen.
                                n=1      Enables echoing of commands to the
                                _
                                         screen (default).


                      Fn        SELECT LINE MODULATION
                       _
                                Selects the line modulation specified by the
                                parameter n.  The line modulation is fixed
                                          _
                                unless auto-detected mode is selected.  The
                                default for this command is 0.

                                Syntax:  "ATF"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects the auto-detect mode.
                                _
                                n=1      Selects V.21 or Bell 103.
                                _
                                n=2      Not supported.
                                _
                                n=3      Selects V.23 as the line modulation
                                _
                                         used in subsequent connections.
                                n=4      Selects V.22 or Bell 212A.
                                _
                                n=5      Selects V.22bis.
                                _
                                n=6      Selects V.32bis or V.32.
                                _
                                n=7      Selects V.32bis, line speed 7200 bps.
                                _
                                n=8      Selects V.32bis or V.32.
                                _
                                n=9      Selects V.32bis, line speed 12200 bps.
                                _
                                n=10     Selects V.32bis, line speed 14400 bps.
                                _





                                       Chapter 1.  Advanced Control Settings  9









                      Hn        SWITCH HOOK CONTROL
                       _

                                Syntax:  "ATH"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Instructs the modem to hang up or
                                _
                                         disconnect.
                                n=1      Instructs the modem to go off the hook
                                _
                                         and enter command mode.


                      In        IDENTIFICATION
                       _
                                Requests the modem to return its product
                                identification information.

                                Syntax:  "ATI"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Displays the product identification
                                _
                                         code.
                                n=1      Displays the ROM (read only memory)
                                _
                                         checksum.
                                n=2      Calculate a checksum for the modem ROM
                                _
                                         and check the value against the stored
                                         checksum value.  The modem returns an
                                         Error or Ok result code, as determined
                                         by the result of the checksum test.
                                n=3      Return the modem ROM version.
                                _
                                n=4      Return the defined identifier string.
                                _
                                n=5      Return the country-code parameter.
                                _
                                n=6      Return the modem data-pump model.
                                _


                      Ln        SPEAKER VOLUME
                       _
                                Controls the speaker volume to the system unit.


                      NOTE:  For PCMCIA digital audio, the "L"n command has no
                                                              _
                      effect.

                                Syntax:  "ATL"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Low volume.
                                _
                                n=1      Low volume (default).
                                _
                                n=2      Medium volume.
                                _
                                n=3      High volume.
                                _









  10  AT Commands









                      Mn        SPEAKER CONTROL
                       _
                                Controls the audio speaker.

                                Syntax:  "ATM"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disables the modem speaker.
                                _
                                n=1      Turns on the modem speaker until the
                                _
                                         carrier has been detected (default).
                                n=2      Instructs the modem speaker to stay on
                                _
                                         at all times.
                                n=3      Enables the speaker after dialing
                                _
                                         until the connection is established.


                      Nn        AUTOMODE ENABLE
                       _
                                Enables or disables automode detection.  The
                                parameter value, if valid, is written into
                                register S31.  The default is n=1.
                                                              _

                                Syntax:  "ATN"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Automode detection is disabled.
                                _
                                n=1      Automode detection is enabled.
                                _
                                         Handshaking will be conducted
                                         according to the EIA/TIA PN-2330
                                         algorithm.


                      On        RETURN TO ONLINE STATE MODE
                       _

                                Syntax:  "ATO"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Switches the modem from command mode
                                _
                                         to online mode without dialing.
                                n=1      Switches from command mode to online
                                _
                                         mode and initiates an equalizer
                                         retrain.


                      Pn        PULSE DIAL AS THE DEFAULT
                       _
                                This command sets pulse dialing as the default
                                dialing mode.  The default for this command is
                                0.

                                Syntax:  "ATP"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Use dial code 0.
                                _
                                n=1      Use dial code 1.
                                _




                                      Chapter 1.  Advanced Control Settings  11









                      Qn        MODEM RESPONSES ENABLED OR DISABLED
                       _

                                Syntax:  "ATQ"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Enables result codes to be issued to
                                _
                                         the screen (default).
                                n=1      Disables result codes to be issued to
                                _
                                         the screen.


                      T         TONE DIAL AS THE DEFAULT
                                This command sets tone dialing as the defult
                                dialing mode.  The modem dials the telephone
                                number using tone dialing.  The T parameter in
                                the dialing string (for tone dialing) is not
                                necessary.

                                Syntax:  "ATT"  ENTER

                      Vn        RESULT-CODE FORMAT
                       _

                                Syntax:  "ATV"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Numeric format.
                                _
                                n=1      Text format (default).
                                _


                      Wn        NEGOTIATION PROGRESS MESSAGES
                       _
                                Enables or disables the following negotiation
                                progress messages.  When the "\V1" setting is
                                valid, the "W1" command overrides that setting
                                and the "\V1" setting is changed to "\V0".
                                When the modem is connected in the direct mode,
                                the following messages are not displayed.

                                Syntax:  "ATW"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Reports only the Line CONNECT speed
                                _
                                         (default).
                                n=1      Reports Line Speed and Error
                                _
                                         correction Protocol.
                                n=2      Reports Line Speed.
                                _


                      COMMAND   DESCRIPTION








  12  AT Commands









                      Xn        EXTEND RESPONSE CODES
                       _
                                Determines which set of responses and calling
                                characteristics are used.

                                Syntax:  "ATX"n  ENTER
                                              _

                                Where "X3" allows blind dialing to be enabled
                                by country parameters, and "X4" sends all
                                messages.

                                This command determines whether the modem
                                recognizes dial tones and busy tones, and what
                                kind of result code should be enabled.  When n
                                                                             _
                                is set for 0, 1, or 3, the modem waits for the
                                time specified by register S6 after going off
                                the hook, then dials regardless of the presence
                                or absence of a dial tone.  This condition,
                                called blind dialing, allows use of the modem
                                in countries where dial tones could vary from
                                one central office to another.  It also allows
                                use of the modem with PBXs that generate unique
                                dial tones that may not otherwise be recognized
                                by the unit.

                                The default setting for this command is n=4.
                                                                        _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      The modem does not recognize dial
                                _
                                         tones or busy tones.  Dial tone wait
                                         time is zero, and blind dialing is
                                         enabled.  The modem returns a CONNECT
                                                                       _______
                                         result code when a connection is
                                         established.
                                n=1      The modem does not recognize dial
                                _
                                         tones or busy tones.  Dial tone wait
                                         time is zero, and blind dialing is
                                         enabled.  The modem returns a CONNECT
                                                                       _______
                                         XXXX result code when a connection is
                                         ____
                                         established, where XXXX reflects the
                                                            ____
                                         serial port speed.
                                n=2      The modem does not recognize busy
                                _
                                         tones, but waits for a dial tone
                                         before dialing.  If a dial tone is not
                                         detected within 5 seconds, a NO DIAL
                                                                      _______
                                         TONE result code is returned.
                                         ____

                                         The modem returns a CONNECT XXXX
                                                             ____________
                                         result code when a connection is
                                         established, where XXXX reflects the
                                                            ____
                                         serial port speed.
                                n=3      The modem does not recognize dial
                                _
                                         tones.  If a busy tone is detected, a
                                         BUSY result code is returned.  Blind
                                         ____



                                      Chapter 1.  Advanced Control Settings  13









                                         dialing is enabled.  The modem returns
                                         a CONNECT XXXX result code when a
                                           ____________
                                         connection is established., where XXXX
                                                                           ____
                                         reflects the serial port speed.
                                n=4      If a dial tone is not detected within
                                _
                                         5 seconds, a NO DIAL TONE result code
                                                      ____________
                                         is returned.  If a busy signal is
                                         detected, a BUSY result code is
                                                     ____
                                         returned.

                                         The modem returns a CONNECT XXXX
                                                             ____________
                                         result code when a connection is
                                         established, where XXXX reflects the
                                                            ____
                                         serial port speed.










































  14  AT Commands









                      The following table lists the modem responses and the
                      result codes that are generated depending upon the "X"n
                                                                            _
                      setting that is used.

                      RESULT CODE LISTING FOR N=0 THROUGH 3
                                              _

                      +------------------+------------------------------------+
                      | NUMERIC RESPONSE | ALPHA RESPONSE                     |
                      +------------------+------------------------------------+
                      |         0        | "OK"                               |
                      +------------------+------------------------------------+
                      |         1        | "CONNECT"                          |
                      +------------------+------------------------------------+
                      |         2        | "RING"                             |
                      +------------------+------------------------------------+
                      |         3        | "NO CARRIER"                       |
                      +------------------+------------------------------------+
                      |         4        | "ERROR"                            |
                      +------------------+------------------------------------+
                      |         5        | "CONNECT 1200"                     |
                      +------------------+------------------------------------+
                      |         6        | "NO DIAL TONE"                     |
                      +------------------+------------------------------------+
                      |         7        | "BUSY"                             |
                      +------------------+------------------------------------+
                      |         8        | "NO ANSWER"                        |
                      +------------------+------------------------------------+
                      |         9        | "CONNECT 600"                      |
                      +------------------+------------------------------------+
                      |        10        | "CONNECT 2400"                     |
                      +------------------+------------------------------------+
                      |        11        | "CONNECT 4800"                     |
                      +------------------+------------------------------------+
                      |        12        | "CONNECT 9600"                     |
                      +------------------+------------------------------------+
                      |        13        | "CONNECT 7200"                     |
                      +------------------+------------------------------------+
                      |        14        | "CONNECT 12 000"                   |
                      +------------------+------------------------------------+
                      |        15        | "CONNECT 14 400"                   |
                      +------------------+------------------------------------+
                      |        16        | "CONNECT 19 200"                   |
                      +------------------+------------------------------------+
                      |        17        | "CONNECT 38 400"                   |
                      +------------------+------------------------------------+
                      |        18        | "CONNECT 57 600"                   |
                      +------------------+------------------------------------+
                      |        24        | "DELAYED"                          |
                      +------------------+------------------------------------+
                      |        32        | "BLACKLISTED"                      |
                      +------------------+------------------------------------+
                      |        33        | "FAX"                              |
                      +------------------+------------------------------------+



                                      Chapter 1.  Advanced Control Settings  15









                      +------------------+------------------------------------+
                      | NUMERIC RESPONSE | ALPHA RESPONSE                     |
                      +------------------+------------------------------------+
                      |        35        | "DATA"                             |
                      +------------------+------------------------------------+

                      RESULT CODE LISTING FOR N=4
                                              _

                      Result codes for "X4" are identical to those for 0
                      through 3 listed above, with the addition of the
                      following codes.

                      +------------------+------------------------------------+
                      | NUMERIC RESPONSE | ALPHA RESPONSE                     |
                      +------------------+------------------------------------+
                      |        40        | "CARRIER 300"                      |
                      +------------------+------------------------------------+
                      |        46        | "CARRIER 1200"                     |
                      +------------------+------------------------------------+
                      |        47        | "CARRIER 2400"                     |
                      +------------------+------------------------------------+
                      |        48        | "CARRIER 4800"                     |
                      +------------------+------------------------------------+
                      |        49        | "CARRIER 7200"                     |
                      +------------------+------------------------------------+
                      |        50        | "CARRIER 9600"                     |
                      +------------------+------------------------------------+
                      |        51        | "CARRIER 12 000"                   |
                      +------------------+------------------------------------+
                      |        52        | "CARRIER 14 400"                   |
                      +------------------+------------------------------------+
                      |        66        | "COMPRESSION: CLASS 5"             |
                      +------------------+------------------------------------+
                      |        67        | "COMPRESSION: V.42bis"             |
                      +------------------+------------------------------------+
                      |        69        | "COMPRESSION : NONE"               |
                      +------------------+------------------------------------+
                      |        76        | "PROTOCOL: NONE"                   |
                      +------------------+------------------------------------+
                      |        77        | "PROTOCOL: LAPM"                   |
                      +------------------+------------------------------------+
                      |        80        | "PROTOCOL: ALT"                    |
                      +------------------+------------------------------------+
                      |        81        | "PROTOCOL: ALT-CELLULAR"           |
                      +------------------+------------------------------------+

                      S-Register Controls = S14









  16  AT Commands









  SERIAL PORT CONTROL
  ___________________

                      The modem can determine the speed, parity, and stop bits
                      from the serial port connection.  The modem will
                      automatically detect speeds between 300 and 57 600 bps
                      with the following data length, parity, and stop bit
                      formats.

                      +-------------+-------------+-------------+-------------+
                      | DATA LENGTH |    PARITY   |  STOP BITS  |    TOTAL    |
                      |             |             |             |    LENGTH   |
                      +-------------+-------------+-------------+-------------+
                      |      7      |     None    |      2      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      7      |     Odd     |      1      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      7      |     Even    |      1      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      7      |     Mark    |      1      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      7      |    Space    |      1      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      8      |     None    |      1      |      10     |
                      +-------------+-------------+-------------+-------------+
                      |      8      |     Odd     |      1      |      11     |
                      +-------------+-------------+-------------+-------------+
                      |      8      |     Even    |      1      |      11     |
                      +-------------+-------------+-------------+-------------+

                      This modem has the capability of automatically adjusting
                      the baud rate of the internal serial port to the physical
                      carrier speed.  The application software will adjust the
                      baud rate of the internal serial port controller to the
                      physical carrier speed by detecting the carrier speed
                      after receiving the CONNECT XXXX message.
                                          ____________


  COMMUNICATION LINK DATA RATE

                      The communications link between the serial port and the
                      modem controller needs to provide full duplex character
                      data at rate fast enough to accommodate the transfer of
                      synchronous T.30 phase C data and V.42bis compressed
                      data.  The data rate should be 4 times faster than the
                      maximum expected communication rate to accommodate
                      V.42bis compression rates.  For example, 57 600 bps is
                      the minimum rate needed to support V.42bis at 14 400 bps.
                      The 19 200 bps rate is sufficient to support facsimile
                      signalling at up to 14 400 bps.  With flow control,
                      changing the DTE to DCE communication link data rate
                      during facsimile operation is not necessary.





                                      Chapter 1.  Advanced Control Settings  17









                      COMMAND   DESCRIPTION

                      Yn        CONTROL LONG-SPACE DISCONNECT
                       _
                                Determines whether the modem disconnects when
                                it receives a continuous break from a remote
                                modem.

                                Syntax:  "ATY"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disabled (default).
                                _
                                n=1      Enabled.
                                _


                      Zn        RESET THE MODEM AND RESTORE PROFILE
                       _

                                Syntax:  "ATZ"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Restores stored profile 0.
                                _
                                n=1      Restores stored profile 1.
                                _



































  18  AT Commands









  EXTENDED AT COMMANDS
  ____________________

                      The following section lists the extended AT commands and
                      their functions.  As with the basic AT commands, each
                      extended command must be preceded by "AT".

                      COMMAND   DESCRIPTION

                      &Cn       DATA CARRIER DETECT (DCD) SIGNAL
                        _

                                Syntax:  "AT&C"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Forces DCD signal to be on at all
                                _
                                         times (default).
                                n=1      DCD on indicates presence of data
                                _
                                         carrier.


                      &Dn       DATA TERMINAL READY (DTR) SIGNAL
                        _
                                Interprets the ON to OFF transition of the DTR
                                signal from the DTE according to the "&"
                                setting as shown in the following table.  This
                                command combines the "&D"n command with the
                                                         _
                                extended "&" commands shown below.

                                Syntax:  "AT&D"n  ENTER
                                               _

                      +-------+-------+---------------------------------------+
                      |   N   |    &  |                                       |
                          _
                      | COMMAN| COMMAN| FUNCTION                              |
                      +-------+-------+---------------------------------------+
                      |  n=0  | &Q0,  | DTR ignored (default).                |
                         _
                      |       | &Q5,  |                                       |
                      |       | &Q6   |                                       |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |       | &Q1,  | Modem hangs up, automatic answer not  |
                      |       | &Q4   | affected.                             |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |       | &Q2,  | Modem hangs up, automatic answer      |
                      |       | &Q3   | inhibited.                            |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |  n=1  | &Q0,  | Asynchronous escape sequence.         |
                         _
                      |       | &Q1,  |                                       |
                      |       | &Q4,  |                                       |
                      |       | &Q5,  |                                       |
                      |       | &Q6   |                                       |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+




                                      Chapter 1.  Advanced Control Settings  19









                      +-------+-------+---------------------------------------+
                      |   N   |    &  |                                       |
                          _
                      | COMMAN| COMMAN| FUNCTION                              |
                      +-------+-------+---------------------------------------+
                      |       | &Q2,  | Modem hangs up, automatic answering   |
                      |       | &Q3   | inhibited.                            |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |  n=2  | &Q0-&Q| Modem hangs up, automatic answering   |
                         _
                      |       |       | inhibited.                            |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |  n=3  | &Q0,  | Modem resets as if the "Z" command    |
                         _
                      |       | &Q1,  | were received.                        |
                      |       | &Q4,  |                                       |
                      |       | &Q5,  |                                       |
                      |       | &Q6   |                                       |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |       | &Q2,  | Modem hangs up, automatic answering   |
                      |       | &Q3   | is inhibited.                         |
                      |       |       |                                       |
                      +-------+-------+---------------------------------------+
                      |       | &Y    | Determines which profile is loaded.   |
                      +-------+-------+---------------------------------------+


                      COMMAND   DESCRIPTION

                      &Fn       RECALL FACTORY DEFAULTS
                        _
                                Instructs the modem to use the factory-set
                                parameters.

                                Syntax:  "AT&F"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Recalls (restores) factory profile 0.
                                _
                                n=1      Recalls (restores) factory profile 1.
                                _


                      &Gn       GUARD TONE SELECT IN ITU-T MODE
                        _
                                Guard tones are always disabled in the U.S.A.

                                Syntax:  "AT&G"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Do not use guard tones (default).
                                _
                                n=1      Disables guard tone.
                                _
                                n=2      Selects a guard tone 1800 Hz.
                                _







  20  AT Commands









                      &Kn       DTE/MODEM FLOW CONTROL
                        _
                                Determines how the modem controls the flow of
                                data between the local DTE and the modem.  When
                                the modem terminal buffer is nearly full, the
                                modem will either send an XOFF or drop CTS
                                (clear to send) to stop the data flow; when the
                                buffer is nearly empty, the modem will either
                                send an XON or raise CTS to resume the data
                                flow.

                                Syntax:  "AT&K"n  ENTER
                                               _

                      MODIFIER  USAGE
                      ________  _____
                      n=0      Disables flow control.
                      _
                      n=3      Enables RTS (request to send)/CTS (default for
                      _
                               data modem).
                      n=4      Enables XON/XOFF.
                      _
                      n=5      Enables transparent XON/XOFF.
                      _
                      n=6      Enables both RTS/CTS and XON/XOFF (default for
                      _
                               fax modem).


                      NOTE:  XON/XOFF is a software-based flow control method,
                      using standard ASCII control characters to pause or
                      resume data transmission.  RTS/CTS pacing, a
                      hardware-based method, uses an electrical signal.


                      Signals are exchanged as follows:

                      +-------------+-----------------------------------------+
                      |  RECEIVING  |                                         |
                      |    MODEM    | TRANSMITTING MODEM                      |
                      +-------------+-----------------------------------------+
                      |   "CTS ON"  | "START SENDING                          |
                      +-------------+-----------------------------------------+
                      |    CTS ON   | RTS ON (ready to send)                  |
                      +-------------+-----------------------------------------+
                      |   CTS OFF   | RTS OFF (stop sending)"                 |
                      +-------------+-----------------------------------------+


                      &Mn       ASYNCHRONOUS/SYNCHRONOUS MODE SELECTION
                        _
                                Determines the DTR operating mode.  The modem
                                treats the "&M" command as a subset of the "&Q"
                                command.

                                Syntax:  "AT&M"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects direct asynchronous mode
                                _
                                         (default).




                                      Chapter 1.  Advanced Control Settings  21









                      &Pn       SELECT PULSE DIAL MAKE/BREAK RATIO
                        _
                                Determines the ratio between the off hook
                                (make) and the on hook (break) pulse dialing
                                intervals.

                                Syntax:  "AT&P"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects a make/break ratio of 39/61 at
                                _
                                         10 pps.  Used in the United States and
                                         Canada (default).
                                n=1      Selects a make/break ratio of 33/67 at
                                _
                                         10 pps.  Used in the United Kingdom
                                         and Hong Kong.


                      &Qn       SYNCHRONOUS/ASYNCHRONOUS MODE
                        _
                                An extension of the "&M" command and is used to
                                control the connection modes permitted. Used in
                                conjunction with S36 and S48.  (also see
                                Chapter 3, "MNP Operation" on page 53).

                                Syntax:  "AT&Q"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Direct asynchronous mode.
                                _
                                n=1      Synchronous connection with
                                _
                                         asynchronous offline command mode.
                                n=2      Same as 1 plus enables DTR dialing of
                                _
                                         directory zero.
                                n=3      Same as 1 plus enables DTR to act as a
                                _
                                         talk/data switch.
                                n=4      Hayes automatic synchronous mode.
                                _
                                n=5      Modem negotiates an error-corrected
                                _
                                         link (default).
                                n=6      Selects asynchronous operation in
                                _
                                         normal mode (that is, speed
                                         buffering).


                      &Rn       RTS/CTS OPTION
                        _
                                Controls the state of the CTS signal.  S is
                                always on in the asynchronous mode unless
                                "AT&K3" has been selected.

                                Syntax:  "AT&R"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      CTS tracks RTS.
                                _
                                n=1      CTS is always active (default).
                                _






  22  AT Commands









                      &Sn       DATA SET READY (DSR) SIGNAL
                        _

                                Syntax:  "AT&S"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Causes DSR signal to be active at all
                                _
                                         times (default).
                                n=1      Causes DSR signal to be active
                                _
                                         according to the V.25 protocol.


                      &Tn       TEST AND DIAGNOSTICS
                        _

                                Syntax:  "AT&T"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Ends any test in progress.
                                _
                                n=1      Runs the local analog loopback test.
                                _
                                n=3      Runs the local digital loopback test.
                                _
                                n=4      Enables the modem to accept a request
                                _
                                         from a remote modem for a digital
                                         loopback test (default).
                                n=5      Instructs the modem to deny a request
                                _
                                         from a remote modem for a digital
                                         loopback test.
                                n=6      Runs the remote digital loopback test.
                                _
                                n=7      Runs the remote digital loopback test
                                _
                                         with a self-test.
                                n=8      Runs the local analog loopback test
                                _
                                         with a self-test.


                      &V        VIEW CURRENT CONFIGURATION AND USER PROFILE
                                Displays the current active configuration,
                                stored user profiles, and the first four stored
                                telephone numbers.  Care should be taken as
                                user input or application software could change
                                these profiles.

                                To return to the factory profile, use the &Fn
                                                                            _
                                command.

                                Syntax:  "AT&V"  ENTER

                      NOTE:  Predefined user profiles and telephone numbers
                      that have been stored via the &Zn=x command are
                                                      ___
                      maintained in the modem's non-volatile random access
                      memory (NVRAM).  The modem initiates a test of the NVRAM
                      when this command is selected.  If the modem's NVRAM is
                      detected as defective by this test, the modem will
                      display:

                            "NVRAM FAILED OR NOT INSTALLED"



                                      Chapter 1.  Advanced Control Settings  23









  +---------------------------------------------------------------------------+
  |                                                                           |
  | SAMPLE CONFIGURATION:  "                                                  |
  |                                                                           |
  | ACTIVE PROFILE:                                                           |
  | B1 E1 F0 L2 M1 N1 P Q0 V1 W1 X4 Y0 &C1 &D2 &G0 &K3 &Q5 &R0 &T4 &X0 &Y0    |
  | S00:000 S01:000 S:02:043 S03:013 S04:010 S05:008 S06:002 S07:050 S08:002  |
  | S09:006 S10:014 S:12:050 S18:000 S24:100 S25:005 S26:001 S36:007 S37:000  |
  | S38:020 S44:104 S46:138 S48:007 S95:044                                   |
  | STORED PROFILE 0:                                                         |
  | B1 E1 F0 L2 M1 N1 P Q0 V1 W1 X4 Y0 &C1 &D2 &G0 &K3 &Q5 &R0 &T4 &X0        |
  | S00:000 S:02:043 S06:002 S07:050 S08:002 S09:006 S10:014 S:12:050 S18:000 |
  | S24:100 S36:007 S37:000 S40:104 S41:003 S44:104 S46:138 S48:007 S95:044   |
  | STORED PROFILE 1:                                                         |
  | B1 E1 F0 L2 M1 N1 P Q0 V1 W1 X4 Y0 &C1 &D2 &G0 &K3 &Q5 &R0 &T4 &X0        |
  | S00:000 S:02:043 S06:002 S07:050 S08:002 S09:006 S10:014 S:12:050 S18:000 |
  | S24:100 S36:007 S37:000 S40:104 S41:003 S44:104 S46:138 S48:007 S95:044   |
  | TELEPHONE NUMBERS:                                                        |
  | 0= ____________________     2= ____________________                       |
  | 1= ____________________     3= ____________________ "                     |
  |                                                                           |
  +---------------------------------------------------------------------------+

                      Under each heading, the top row characters ("B"x, "E"x,
                                                                     _     _
                      "F"x, "L"x, and so on) refer to the AT commands that are
                         _     _
                      either active or currently stored.  The following rows of
                      characters, indicated by "S"xx:xxx refer to the
                                                  ______
                      S-registers that are active or currently stored and their
                      settings.

                      This command also shows the first four currently stored
                      telephone numbers.  To view the full list of stored
                      telephone numbers, use the "\F" command.























  24  AT Commands









                      COMMAND   DESCRIPTION

                      &Wn       STORE USER PROFILE
                        _
                                Saves the current configuration into
                                nonvolatile RAM as one of two user profiles.
                                Use this command to write initialization
                                strings.

                                Syntax:  "AT&W"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Saves as user profile 0.
                                _
                                n=1      Saves as user profile 1.
                                _


                      &Xn       SELECT CLOCK SOURCE
                        _
                                Selects the source of the transmission clock
                                for the synchronous mode of operation.  The
                                parameter value, if valid, is written to S27
                                (bits 4 and 5).  In asynchronous mode, the
                                transmission and receipt clocks are turned off.

                                Syntax:  "AT&X"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects internal timing.
                                _
                                n=1      Selects external timing.
                                _
                                n=2      Selects slave receiving timing.  The
                                _
                                         transmission clock signal is derived
                                         from the incoming carrier.


                      &Yn       DESIGNATE DEFAULT USER PROFILE
                        _
                                Specifies which of two user profiles will be
                                loaded into the active configuration at
                                power-up.

                                Syntax:  "AT&Y"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Selects user profile 0 (default).
                                _
                                n=1      Selects user profile 1.
                                _


                      &Zn=x     STORE PHONE NUMBER
                        _ _
                                Stores a 36-digit dial string (x) in the
                                                               _
                                specified entry (0-3) for later dialing.  An
                                individual entry can be up to 40 digits, but
                                the total number of digits in all entries
                                cannot exceed 114.

                                Syntax:  "AT&Z"n=x  ENTER
                                               ___




                                      Chapter 1.  Advanced Control Settings  25









                      )Mn       ENABLE CELLULAR POWER-LEVEL ADJUSTMENT
                        _
                                This command determines whether the modem
                                automatically adjusts the transmit power-level
                                when a cellular telephone is being used.  The
                                power-level is adjusted during link-negotiation
                                to accommodate the signal requirements of the
                                cellular telephone.  The default for this
                                command is 0.

                                Syntax:  "AT)"n  ENTER
                                              _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disable power-level adjustment.
                                _
                                n=1      Enable power-level adjustment.
                                _
                                n=2      Enables power level adjustment during
                                _
                                         link negotiation, then power level
                                         remains fixed.


                      -Kn       MNP EXTENDED SERVICES
                        _
                                This command enables and disables the
                                conversion of the V.42 LAPM connection to an
                                MNP 10 connection.  The default for this
                                command is 1.

                                Syntax:  "AT-K"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disable conversion from V.42 LAPM to
                                _
                                         MNP 10
                                n=1      Enable conversion from V.42 LAPM to
                                _
                                         MNP 10
                                n=2      Enable conversion from V.42 LAPM to
                                _
                                         MNP 10; inhibits MNP Extended Services
                                         initiation during V.42 LAPM answer
                                         mode detection phase.




















  26  AT Commands









                      -Qn       ENABLE FALLBACK TO V.22/V.22BIS.
                        _
                                This command determines whether the modem goes
                                from MNP 10 to V.22 or V.21bis if the MNP10
                                link cannot be established.  The default for
                                this command is 1.

                                Syntax:  "AT-Q"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Disable fallback to V.22/V.22bis:  The
                                _
                                         modem will only decrease the line
                                         speed to 4800 bps while trying to
                                         establish a link.
                                n=1      Enables fallback to V.22/V.22bis:  The
                                _
                                         modem will decrease the line speed to
                                         1200 bps while trying to establish a
                                         link.


                      *Hn       LINK NEGOTIATION SPEED
                        _
                                This command controls the connection speed for
                                link negotiations before upshift occurs between
                                two MNP 10 modems.  The parameter value, if
                                valid, is written to S28 bits 6 and 7.

                                Syntax:  "AT*H"n  ENTER
                                               _

                                MODIFIER  USAGE
                                ________  _____
                                n=0      Link negotiation occurs at this
                                _
                                         highest supported speed (default).
                                n=1      Link negotiation occurs at 1200 bps;
                                _
                                         used primarily for establishing
                                         cellular connections.
                                n=2      Link negotiation occurs at 4800 bps;
                                _
                                         used primarily to negotiate an MNP 10
                                         connection on less than average
                                         quality telephone lines.



















                                      Chapter 1.  Advanced Control Settings  27

































































  28  AT Commands









  CHAPTER 2.  S-REGISTERS
  _______________________





                      Modem command language uses a set of indicators or
                      registers, called S-registers.  The values of the
                      S-registers regulate the operation of the modem, as well
                      as the function of certain AT commands.

                      This section defines the purpose of the modem registers,
                      explains how to read and change register values, explains
                      how to access a register repeatedly, and subsequently
                      lists the registers and describes their functions.  These
                      registers affect various operating characteristics and
                      allow you to obtain information about the modem, as well
                      as test the modem.  Each register has a factory-set value
                      which you can read or change to fit your needs.

                      For instance, S-register 6, or S6=n, defines the length
                                                        _
                      of time the modem waits for a dial tone.  In this case,
                      the acceptable range is 2-255 (in seconds) with a default
                      value of 2.  When the S-register is set to S6=2, the
                      modem waits two seconds for a dial tone before dialing
                      the first digit of the telephone number.

                      There are protocols that various domestic and
                      international standards use for modem performance and
                      reliability.  The protocols are activated and controlled
                      by a variety of extended AT commands and S-registers.

                      NOTES:
                      1.  Because of improvements to the usability of this
                      product, the default value for the S-registers specified
                      in this manual might differ from the actual default value
                      of your modem.  See "Reading a Register Value" on page 30
                      to determine the actual default value.
                      2.  Communication software programs often have default
                      values of their own that are written to the modem when
                      the modem is brought online or connected.  Refer to the
                      documentation that came with the communication software
                      product you are using to determine how to view and change
                      these default values.












  (C) Copyright IBM Corp. 1995                                               29









  READING A REGISTER VALUE
  ________________________

                      To read the current value of a register, start from the
                      command mode in your communications software.  Type the
                      following:

                          "ATSn?"
                          and press ENTER

                      Where n is a register number.  The modem responds with
                            _
                      the decimal value of the register in 3-digit form.  This
                      is followed by "OK" or "0".

                      To read values from more than one register, type the
                      following from the command mode:

                          "ATSn?Sn?"
                          and press ENTER


                      For example, to read the register values of S0 and S1,
                      type the following:

                          "ATS0?S1?"
                          and press ENTER

                      The modem displays the first register value, a carriage
                      return, the next register value, a carriage return, and
                      "OK" or "0".


  HOW TO SET BIT-MAPPED REGISTERS
  _______________________________

                      To set or change bit-mapped registers, you should have a
                      sound working knowledge of binary notation.  Bit-mapped
                      S-register values are calculated as follows.  Each bit
                      (0-7) has a corresponding decimal value as shown below.
                      If the bit is on, it has that corresponding value; if the
                      bit is off, its value is zero.

                                       BIT DECIMAL  BIT  DECIMAL
                                       0     1       4     16
                                       1     2       5     32
                                       2     4       6     64
                                       3     8       7    128

                      Some bit-mapped registers combine bits, which makes
                      calculating values even more complex.  For example, if
                      bits 3 and 4 were combined to offer four options (0-3),
                      the value would be calculated this way:






  30  AT Commands









                      +-------+-------+-------+-------+-------+---------------+
                      | BIT 4 |   16  | BIT 3 |   8   | OPTION| VALUE         |
                      +-------+-------+-------+-------+-------+---------------+
                      |   0   |   0   |   0   |   0   |   0   | 0             |
                      +-------+-------+-------+-------+-------+---------------+
                      |   0   |   16  |   1   |   8   |   1   | 24 (16+8)     |
                      +-------+-------+-------+-------+-------+---------------+
                      |   1   |   32  |   0   |   16  |   2   | 48 (32+16)    |
                      +-------+-------+-------+-------+-------+---------------+
                      |   1   |   48  |   1   |   24  |   3   | 72 (48+24)    |
                      +-------+-------+-------+-------+-------+---------------+


  CHANGING A REGISTER VALUE
  _________________________

                      To change a register value, use the "S"n command
                                                             _
                      ("ATS"n=v), where n is a register number and v is the new
                            _ _         _                          _
                      value you want to assign to the register.  For example,
                      type the following:

                          "ATS0=3"
                          and press ENTER

                      to have the modem automatically answer incoming calls
                      after the third ring.  The changed values remain in
                      effect until the modem is turned off and on or reset.
                      The modem then returns to its default settings.


  ACCESSING A REGISTER REPEATEDLY
  _______________________________

                      The modem automatically places a pointer at the last
                      register whose value was read or changed.  The pointer
                      provides a fast way of displaying or changing register
                      values.

                      Type the following:

                          "ATS0?"
                          and press ENTER

                      to read the value of register S0.  The modem responds
                      with the value of register S0 and places a pointer at
                      that register automatically.

                      Type the following:

                          "AT=0"
                          and press ENTER

                      to change the value in register S0 to 0. (Neither the "S"
                      command nor the register number has to be specified; the
                      pointer handles this task.)



                                                    Chapter 2.  S-Registers  31









                      To read the S0 value, type the following:

                          "AT?"
                          and press ENTER.


                      NOTE:  The pointer remains set at the last register
                      accessed until the "S" command is used to read or change
                      the value of another register.  The pointer is then set
                      to the register whose value is displayed or changed.




  S-REGISTER DESCRIPTIONS
  _______________________

                      The tables on the following pages list the S-registers
                      and their functions.  For most S-registers, it is
                      necessary to set only the register value.  However, some
                      S-registers require that a bit-mapped value be entered.
                      See "How to Set Bit-Mapped Registers" on page 30 for
                      further information.


































  32  AT Commands









  S-REGISTER TABLE
  ________________

                      The table on the following pages lists the available
                      S-registers, a brief description of their functions, and
                      the page on which their full descriptions and available
                      parameters can be found.

                      +--------+-----------------------------------------+----+
                      | S-REGIS|EDESCRIPTION                             | PAG|
                      +--------+-----------------------------------------+----+
                      | S0     | Automatic answer                        | 35 |
                      +--------+-----------------------------------------+----+
                      | S1     | Count incoming rings                    | 35 |
                      +--------+-----------------------------------------+----+
                      | S2     | Escape character value                  | 35 |
                      +--------+-----------------------------------------+----+
                      | S3     | Carriage return character               | 35 |
                      +--------+-----------------------------------------+----+
                      | S4     | Line feed character                     | 35 |
                      +--------+-----------------------------------------+----+
                      | S5     | Backspace character                     | 35 |
                      +--------+-----------------------------------------+----+
                      | S6     | Wait time for blind dialing             | 35 |
                      +--------+-----------------------------------------+----+
                      | S7     | Wait for carrier after dial             | 36 |
                      +--------+-----------------------------------------+----+
                      | S8     | Pause time for dial delay (comma        | 36 |
                      |        | attribute)                              |    |
                      +--------+-----------------------------------------+----+
                      | S9     | Carrier detect                          | 36 |
                      +--------+-----------------------------------------+----+
                      | S10    | Lost carrier to hang up delay           | 36 |
                      +--------+-----------------------------------------+----+
                      | S11    | DTMF tone duration                      | 36 |
                      +--------+-----------------------------------------+----+
                      | S12    | Escape code guard time                  | 36 |
                      +--------+-----------------------------------------+----+
                      | S14    | General bit-mapped options              | 37 |
                      +--------+-----------------------------------------+----+
                      | S16    | Diagnostic status register              | 38 |
                      +--------+-----------------------------------------+----+
                      | S18    | Test timer for diagnostic test          | 38 |
                      +--------+-----------------------------------------+----+
                      | S19    | Autosync bit-mapped options             | 39 |
                      +--------+-----------------------------------------+----+
                      | S20    | SCLD/HDLC address                       | 39 |
                      +--------+-----------------------------------------+----+
                      | S21    | V.24/General bit-mapped options and     | 40 |
                      |        | status                                  |    |
                      +--------+-----------------------------------------+----+
                      | S22    | Speaker control/result status           | 41 |
                      +--------+-----------------------------------------+----+
                      | S23    | Serial port control                     | 42 |
                      +--------+-----------------------------------------+----+


                                                    Chapter 2.  S-Registers  33









                      +--------+-----------------------------------------+----+
                      | S-REGIS|EDESCRIPTION                             | PAG|
                      +--------+-----------------------------------------+----+
                      | S24    | Sleep inactivity timer                  | 42 |
                      +--------+-----------------------------------------+----+
                      | S25    | DTR detection delay                     | 42 |
                      +--------+-----------------------------------------+----+
                      | S26    | RTS to CTS delay interval               | 42 |
                      +--------+-----------------------------------------+----+
                      | S27    | General mode selection                  | 43 |
                      +--------+-----------------------------------------+----+
                      | S28    | General mode selection (part 2)         | 44 |
                      +--------+-----------------------------------------+----+
                      | S29    | Flash modifier                          | 44 |
                      +--------+-----------------------------------------+----+
                      | S30    | Automatic disconnect activity timer     | 45 |
                      +--------+-----------------------------------------+----+
                      | S31    | Automatic line speed control            | 45 |
                      +--------+-----------------------------------------+----+
                      | S32    | XON                                     | 45 |
                      +--------+-----------------------------------------+----+
                      | S33    | XOFF                                    | 45 |
                      +--------+-----------------------------------------+----+
                      | S36    | LAPM failure control                    | 46 |
                      +--------+-----------------------------------------+----+
                      | S37    | Line connection speed                   | 47 |
                      +--------+-----------------------------------------+----+
                      | S38    | Forced hang up                          | 47 |
                      +--------+-----------------------------------------+----+
                      | S39    | Flow control                            | 48 |
                      +--------+-----------------------------------------+----+
                      | S40    | MNP error correction controls           | 48 |
                      +--------+-----------------------------------------+----+
                      | S41    | Compression controls                    | 49 |
                      +--------+-----------------------------------------+----+
                      | S46    | V.42bis data compression                | 49 |
                      +--------+-----------------------------------------+----+
                      | S48    | V.42bis negotiation                     | 49 |
                      +--------+-----------------------------------------+----+
                      | S82    | Break handling option                   | 49 |
                      +--------+-----------------------------------------+----+
                      | S86    | Connection failure code                 | 50 |
                      +--------+-----------------------------------------+----+
                      | S95    | Result code control                     | 50 |
                      +--------+-----------------------------------------+----+
                      | S201   | Cellular transmit level                 | 51 |
                      +--------+-----------------------------------------+----+









  34  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S0 | 0-2|5Rin|s 0 | AUTOMATIC ANSWER - The number of rings until          |
                        ___________________
  |    |    |    |    | automatic answer.  If the register is set to zero,    |
  |    |    |    |    | modem does not answer.                                |
  +----+----+----+----+-------------------------------------------------------+
  | S1 | 0-2|5Rin|s 0 | COUNT INCOMING RINGS - This register contains the     |
                        _______________________
  |    |    |    |    | number of rings detected by the modem.  If there is   |
  |    |    |    |    | no RING for 8 seconds, this register is cleared to    |
                           ____
  |    |    |    |    | zero.                                                 |
  +----+----+----+----+-------------------------------------------------------+
  | S2 | 0-2|5ASC|I43 | ESCAPE CHARACTER VALUE - This register defines an     |
                        _________________________
  |    |    | dec|mal | ASCII decimal value of the escape character.  The     |
  |    |    |    |    | default setting is an ASCII "+" and the escape        |
  |    |    |    |    | sequence is "+++".  A value over 127 disables the     |
  |    |    |    |    | escape sequence.                                      |
  +----+----+----+----+-------------------------------------------------------+
  | S3 | 0-1|7ASC|I13 | CARRIAGE RETURN CHARACTER - Contains the ASCII value  |
                        ____________________________
  |    |    | dec|mal | of the character used to send a carriage return.      |
  |    |    |    |    | This character ends both commands and result codes.   |
  +----+----+----+----+-------------------------------------------------------+
  | S4 | 0-1|7ASC|I10 | LINE FEED CHARACTER - Contains the ASCII value of the |
                        ______________________
  |    |    | dec|mal | character used to send a line feed.  The modem sends  |
  |    |    |    |    | the line feed character after a carriage return only  |
  |    |    |    |    | when word responses are sent.                         |
  +----+----+----+----+-------------------------------------------------------+
  | S5 | 0-3| ASC|I 8 | BACKSPACE CHARACTER - Contains the ASCII value of the |
                        ______________________
  |    |    | dec|mal | character used to backspace.  This character is both  |
  |    |    |    |    | the character created by pressing the BACKSPACE key   |
  |    |    |    |    | and the character echoed to move the cursor to the    |
  |    |    |    |    | left.                                                 |
  +----+----+----+----+-------------------------------------------------------+
  | S6 | 2-2|5Sec|nd2 | WAIT TIME FOR BLIND DIALING - Sets the length of      |
                        ______________________________
  |    |    |    |    | time, in seconds, to pause after the modem goes off   |
  |    |    |    |    | the hook before the modem dials the first digit of    |
  |    |    |    |    | the telephone number.                                 |
  +----+----+----+----+-------------------------------------------------------+


















                                                    Chapter 2.  S-Registers  35









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S7 | 1-2|5Sec|n50 | WAIT FOR CARRIER AFTER DIAL -                         |
                        ______________________________
  |    |    |    |    | Defines the following three delay times:              |
  |    |    |    |    | (1) The delay time that the modem waits for a carrier |
  |    |    |    |    | after dialing and before hanging up.  If the modem    |
  |    |    |    |    | does not detect a carrier within the defined time,    |
  |    |    |    |    | the modem disconnects the line and returns a NO       |
                                                                     __
  |    |    |    |    | CARRIER result code.                                  |
                        _______
  |    |    |    |    | (2) The delay time the modem will wait for a dial     |
  |    |    |    |    | tone after the modem detects a "W" parameter in the   |
  |    |    |    |    | dial string.  If a dial tone is not detected after    |
  |    |    |    |    | the time specified in this register, the modem will   |
  |    |    |    |    | disconnect the line and return a NO DIAL TONE result  |
                                                         ____________
  |    |    |    |    | code.                                                 |
  |    |    |    |    | (3) The delay time the modem will wait for silence    |
  |    |    |    |    | after the modem detects an "@" in the dial string.    |
  |    |    |    |    | If silence is not detected within the specified time, |
  |    |    |    |    | the modem will hang up and return a NO ANSWER result  |
                                                            _________
  |    |    |    |    | code.                                                 |
  +----+----+----+----+-------------------------------------------------------+
  | S8 | 0-2|5Sec|nd2 | PAUSE TIME FOR DIAL DELAY (COMMA ATTRIBUTE) -         |
                        _____________________________________________
  |    |    |    |    | Determines how long the modem should pause when it    |
  |    |    |    |    | sees a comma in the dialing string.                   |
  +----+----+----+----+-------------------------------------------------------+
  | S9 | 1-2|5Sec|n6/1| CARRIER DETECT - Determines the amount of time (in    |
                        _________________
  |    |    |    |    | tenths of a second) from when the modem recognizes a  |
  |    |    |    |    | loss of carrier to when it will hang up.              |
  +----+----+----+----+-------------------------------------------------------+
  | S10| 1-2|5Sec|n14(|.LOST CARRIER TO HANG UP DELAY - Sets the length of    |
                        ________________________________
  |    |    |    |    | time (in tenths of a second) that the modem waits     |
  |    |    |    |    | before hanging up after the loss of a carrier.  This  |
  |    |    |    |    | allows for a temporary carrier loss without causing   |
  |    |    |    |    | the local modem to disconnect.  When register S10 is  |
  |    |    |    |    | set to 255, the modem functions as if a carrier is    |
  |    |    |    |    | always present.  The actual interval the modem waits  |
  |    |    |    |    | before disconnecting is the value in S10 minus the    |
  |    |    |    |    | value in S9.  If this value is set smaller than the   |
  |    |    |    |    | value contained in S9, the modem disconnects before   |
  |    |    |    |    | it recognizes its carrier.                            |
  +----+----+----+----+-------------------------------------------------------+
  | S11| 0-2|5ms | 95 | DTMF TONE DURATION - Defines the duration of DTMF     |
                        _____________________
  |    |    |    | ms | tones, in milliseconds, for tone dialing.  The length |
  |    |    |    |    | of pause between each DTMF tone is the same as this   |
  |    |    |    |    | duration time.                                        |
  +----+----+----+----+-------------------------------------------------------+
  | S12| 0-2|5Sec|n50(|)ESCAPE CODE GUARD TIME - Controls the delay time, in  |
                        _________________________
  |    |    |    |    | one-fiftieth second intervals, before and after       |
  |    |    |    |    | typing escape sequence codes.                         |
  +----+----+----+----+-------------------------------------------------------+





  36  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S14| N/A| -- | 138| Bit-mapped registers                                  |
  |    |    |    | (8A|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | GENERAL BIT-MAPPED OPTIONS - Provides the following functions:       |
         _____________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Ignored                                               |
  |    | 0  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | "ATE" (command echo)                                  |
  |    | 1  |    |    | 0  Do not echo commands                               |
  |    |    |    |    | 1  Echo commands                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | "ATQ" (result code display)                           |
  |    | 2  |    |    | 0  Send responses                                     |
  |    |    |    |    | 1  Do not send responses                              |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | "ATV" (word or number responses)                      |
  |    | 3  |    |    | 0  Send number responses                              |
  |    |    |    |    | 1  Send word responses                                |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 4  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Dial method ("ATP" or "ATT")                          |
  |    | 5  |    |    | 0  Touch-tone ("T")                                   |
  |    |    |    |    | 1  Pulse ("P")                                        |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 6  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | Answer/originate operation                            |
  |    | 7  |    |    | 0  Answer ("A" and "R")                               |
  |    |    |    |    | 1  Originate ("D")                                    |
  +----+----+----+----+-------------------------------------------------------+

















                                                    Chapter 2.  S-Registers  37









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S16| N/A| -- | 0  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | DIAGNOSTIC STATUS REGISTER - Provides the following functions:       |
         _____________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Local analog loopback test                            |
  |    | 0  |    |    | 0  Disabled ("&T0")                                   |
  |    |    |    |    | 1  Enabled ("&T")                                     |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Not used                                              |
  |    | 1  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Local digital loopback test                           |
  |    | 2  |    |    | 0  Disabled ("&T0")                                   |
  |    |    |    |    | 1  Enabled ("&T3")                                    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Remote digital loopback test                          |
  |    | 3  |    |    | 0  Disabled ("&T0")                                   |
  |    |    |    |    | 1  Enabled ("&T6")                                    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Initiate remote digital loopback                      |
  |    | 4  |    |    | 0  Loopback not in progress ("&T0")                   |
  |    |    |    |    | 1  Loopback in progress ("&T7")                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Remote digital loopback with error count              |
  |    | 5  |    |    | 0  Disabled ("&T0")                                   |
  |    |    |    |    | 1  Enabled ("&T7")                                    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Local analog loopback with self-test                  |
  |    | 6  |    |    | 0  Disabled ("&T0")                                   |
  |    |    |    |    | 1  Enabled ("&T8")                                    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Not used                                              |
  |    | 7  |    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+
  | S18| 0-2|5Sec|nd0 | TEST TIMER FOR DIAGNOSTIC TEST                        |
                        ______________________________
  +----+----+----+----+-------------------------------------------------------+















  38  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S19| N/A| -- | 0  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | AUTOSYNC BIT MAPPED OPTIONS - Provides the following functions:      |
         ______________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 0  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | BSC/HDLC Format Select                                |
  |    | 1  |    |    | 0  Bisynchronous format select                        |
  |    |    |    |    | 1  HDLC format select                                 |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Address detection enabled/disabled                    |
  |    | 2  |    |    | 0  Disabled                                           |
  |    |    |    |    | 1  Enabled                                            |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | NRZI/NZI coding selection                             |
  |    | 3  |    |    | 0  NRZI                                               |
  |    |    |    |    | 1  NZI                                                |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Idle indicator select                                 |
  |    | 4  |    |    | 0  Mark idle                                          |
  |    |    |    |    | 1  Flag/sync idle                                     |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 5  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 6  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 7  |    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+
  | S20| 0-2|5-- |  0 | SDLC/HDLC ADDRESS - Defines either the SDLC/HDLC      |
                        ____________________
  |    |    |    |    | address (if S20 bit 0 is 1), or the BSC Sync          |
  |    |    |    |    | character (if S20 bit 0 is 0).  This bit is active    |
  |    |    |    |    | only if the modem is operating in autosync mode.      |
  |    |    |    |    | Both registers S19 and S20 must be set before         |
  |    |    |    |    | attempting autosync operation.  For more information  |
  |    |    |    |    | on autosync operation, refer to page 22.              |
  +----+----+----+----+-------------------------------------------------------+











                                                    Chapter 2.  S-Registers  39









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S21| N/A| -- | 4  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | V.24/GENERAL BIT MAPPED OPTIONS/STATUS - Provides the following      |
         _________________________________________
  |    | functions:                                                           |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Set by the "AT&J" command, but otherwise ignored.     |
  |    | 0  |    |    | 0  "AT&J0"                                            |
  |    |    |    |    | 1  "AT&J1"                                            |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 1  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | CTS behavior ("AT&R"n)                                |
                                            _
  |    | 2  |    |    | 0  CTS tracks RTS ("AT&R0")                           |
  |    |    |    |    | 1  CTS is always on ("AT&R1")                         |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 00 | DTR behavior ("AT&D"n)                                |
                                            _
  |    | 3, |    |    | 00 "&D0" selected                                     |
  |    | 4  |    |    | 01 "&D1" selected                                     |
  |    |    |    |    | 10 "&D2" selected                                     |
  |    |    |    |    | 11 "&D3" selected                                     |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | RLSD (DCD) behavior                                   |
  |    | 5  |    |    | 0  "AT&C0" selected                                   |
  |    |    |    |    | 1  "AT&C1" selected                                   |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | DSR behavior                                          |
  |    | 6  |    |    | 0  DSR is always active ("&S0")                       |
  |    |    |    |    | 1  DSR is active when handshaking begins ("&S1")      |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Long space disconnect                                 |
  |    | 7  |    |    | 0  Disabled ("Y0")                                    |
  |    |    |    |    | 1  Enabled ("Y1")                                     |
  +----+----+----+----+-------------------------------------------------------+

















  40  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S22| N/A| -- | 117| Bit-mapped registers:                                 |
  |    |    |    | (75|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | SPEAKER CONTROL AND RESULT STATUS - Provides the following           |
         ____________________________________
  |    | functions:                                                           |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 01 | Speaker volume ("ATL"n)                               |
                                             _
  |    | 0, |    |    | 00 OFF ("L0")                                         |
  |    | 1  |    |    | 01 Low volume ("L1")                                  |
  |    |    |    |    | 10 Medium volume ("L2")                               |
  |    |    |    |    | 11 High volume ("L3")                                 |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 01 | Speaker control                                       |
  |    | 2, |    |    | 00 Speaker turned off ("M0")                          |
  |    | 3  |    |    | 01 Speaker on until carrier detected ("M1")           |
  |    |    |    |    | 10 Speaker always on ("M2")                           |
  |    |    |    |    | 11 Speaker on until carrier detected, off when        |
  |    |    |    |    | dialing ("M3")                                        |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 111| Limit result codes                                    |
  |    | 4, |    |    | 000     "X0"                                          |
  |    | 5, |    |    | 100     "X1"                                          |
  |    | 6  |    |    | 101     "X2"                                          |
  |    |    |    |    | 110     "X3"                                          |
  |    |    |    |    | 111     "X4"                                          |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 7  |    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+






















                                                    Chapter 2.  S-Registers  41









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S23| N/A| -- | 55 | Bit-mapped registers                                  |
  |    |    |    | (37|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | SERIAL PORT CONTROL - Provides the following functions:              |
         ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | Grant RDL                                             |
  |    | 0  |    |    | 0  RDL is not permitted ("&T5")                       |
  |    |    |    |    | 1  RDL is permitted ("&T4")                           |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 011| Local DTE rate                                        |
  |    | 1, |    |    | 000     0-300 bps                                     |
  |    | 2, |    |    | 001     600 bps                                       |
  |    | 3  |    |    | 010     1200 bps                                      |
  |    |    |    |    | 011     2400 bps                                      |
  |    |    |    |    | 100     4800 bps                                      |
  |    |    |    |    | 101     9600 bps                                      |
  |    |    |    |    | 110     19 200 bps                                    |
  |    |    |    |    | 111     38 400 bps                                    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 11 | Parity option                                         |
  |    | 4, |    |    | 00 Even                                               |
  |    | 5  |    |    | 01 Not used                                           |
  |    |    |    |    | 10 Odd                                                |
  |    |    |    |    | 11 None                                               |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 00 | Guard tones                                           |
  |    | 6, |    |    | 00 None ("&G0")                                       |
  |    | 7  |    |    | 01 None ("&G1")                                       |
  |    |    |    |    | 10 1800 Hz ("&G2")                                    |
  +----+----+----+----+-------------------------------------------------------+
  | S24| 0-2|5Sec|nd0 | SLEEP INACTIVITY TIMER - If the value programmed into |
                        _________________________
  |    |    |    |    | this register is zero, this feature is disabled.  The |
  |    |    |    |    | timer is reset on any DTE activity.  If the timer     |
  |    |    |    |    | expires, the modem goes into sleep mode.              |
  +----+----+----+----+-------------------------------------------------------+
  | S25| 0-2|5Sec|nd5 | DTR DETECTION DELAY - The DTR signal must be stable   |
                        ______________________
  |    |    |    |    | for the period of time specified by S25 for the modem |
  |    |    |    |    | to detect a valid DTR signal on-to-off transition.    |
  +----+----+----+----+-------------------------------------------------------+
  | S26| 0-2|5Sec|nd1 | RTS TO CTS DELAY INTERVAL - Delay interval (in        |
                        ____________________________
  |    |    |    |    | hundredths of a second) that the modem waits before   |
  |    |    |    |    | it sets the CTS signal active after it detects an     |
  |    |    |    |    | INACTIVE-->ACTIVE transition on the RTS signal.  See  |
  |    |    |    |    | page 22 for further information.                      |
  +----+----+----+----+-------------------------------------------------------+






  42  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S27| N/A| -- | 73 | Bit-mapped registers                                  |
  |    |    |    | (49|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | GENERAL MODE SELECTION - Provides the following functions:           |
         _________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Bit 301  Mode selection                               |
  |    | 0, |    |    |     000 "AT&M0" or "AT&Q0"                            |
  |    | 1, |    |    |     001 "AT&M1" or "AT&Q1"                            |
  |    | 3  |    |    |     010 "AT&M2" or "AT&Q2"                            |
  |    |    |    |    |     011 "AT&M3" or "AT&Q3"                            |
  |    |    |    |    |     100 "AT&Q4"                                       |
  |    |    |    |    |     101 "AT&Q5" (default)                             |
  |    |    |    |    |     110 "AT&M0""AT&Q6"                                |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Leased line control (not supported)                   |
  |    | 2  |    |    | 0  Dial up line ("&L0")                               |
  |    |    |    |    | 1  Leased line ("&L1")                                |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 00 | Clock source selection                                |
  |    | 4, |    |    | 0  Internal clock ("&X0")                             |
  |    | 5  |    |    | 1  External clock ("&X1")                             |
  |    |    |    |    | 2  Slave clock ("&X2")                                |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | Bell/ITU-T select                                     |
  |    | 6  |    |    | 0  ITU-T V.22/V.22bis standard ("B0")                 |
  |    |    |    |    | 1  Bell 212A standard ("B1")                          |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 7  |    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+





















                                                    Chapter 2.  S-Registers  43









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S28| N/A| -- | 00 | Bit-mapped registers                                  |
  |    |    |    | h  |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | GENERAL MODE SELECTION (PART 2) - This register stores the settings  |
         __________________________________
  |    | for the MNP-10 negotiation speed as well as the parameters to be     |
  |    | used for dialing when the modem is set up in pulse mode instead of   |
  |    | its default tone dialing mode.  Provides the following functions:    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | V.23 split screen                                     |
  |    | 0  |    |    | 0  disabled                                           |
  |    |    |    |    | 1  enabled                                            |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | V.23 split screen direction                           |
  |    | 1  |    |    | 0  75 Tx/1200 Rx(%F1)                                 |
  |    |    |    |    | 1  1200 Tx/75 Rx(%F2)                                 |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved (always set to 0)                            |
  |    | 2  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Pulse dialing ("&P"n)                                 |
                                           _
  |    | 3, |    |    | 0  512 ("&P0")                                        |
  |    | 4  |    |    | 1  1024 ("&P1")                                       |
  |    |    |    |    | 2  2048 ("&P2")                                       |
  |    |    |    |    | 3  4096 ("&P3")                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 5  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | MNP link negotiation speed                            |
  |    | 6, |    |    | 0  Link negotiation at highest speed ("AT*H0")        |
  |    | 7  |    |    | 1  Link negotiation at 1200 bps ("AT*H1")             |
  |    |    |    |    | 2  Link negotiation at 4800 bps ("AT*H2")             |
  +----+----+----+----+-------------------------------------------------------+
  | S29| 0-2|5Sec|nd0 | FLASH MODIFIER - Delay interval (in milliseconds) for |
                        _________________
  |    |    |    |    | the flash modifier.  This can be limited since it is  |
  |    |    |    |    | a country-dependent modifier.                         |
  +----+----+----+----+-------------------------------------------------------+














  44  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S30| 0-2|5Sec|nd0 | AUTOMATIC DISCONNECT INACTIVITY TIMER - This register |
                        ________________________________________
  |    |    |    |    | is used to set the amount of time, in ten second      |
  |    |    |    |    | units, that the modem stays online before             |
  |    |    |    |    | disconnecting its link when no data is being sent or  |
  |    |    |    |    | received.  When the modem is in an error-correction   |
  |    |    |    |    | mode (either MNP or V.42bis), the timer is reset      |
  |    |    |    |    | whenever any data is received or transmitted.  When   |
  |    |    |    |    | the modem is connected in any other mode, any data    |
  |    |    |    |    | transmitted resets the timer.  This timer is inactive |
  |    |    |    |    | when the modem is operating in synchronous mode.      |
  |    |    |    |    | NOTE - The default parameter might change depending   |
  |    |    |    |    | upon which country the modem is designed for.         |
  +----+----+----+----+-------------------------------------------------------+
  | S31| N/A| -- | 2  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | AUTOMATIC LINE SPEED CONTROL - Provides the following functions:     |
         _______________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 0  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | Automatic line speed detection                        |
  |    | 1  |    |    | 0  Automatic line speed detection disabled ("ATN0")   |
  |    |    |    |    | 1  Automatic line speed detection enabled ("ATN1")    |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 00 | Error correction progress message reporting           |
  |    | 2, |    |    | 00 Report DTE speed only ("ATW0")                     |
  |    | 3  |    |    | 01 Full report ("ATW1")                               |
  |    |    |    |    | 10 Report DCE speed only ("ATW2")                     |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 4-7|    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+
  | S32| 0-2|5ASC|I17 | XON - This register contains the XON character used   |
                        ______
  |    |    |    |    | when the modem is using XON/XOFF flow control.        |
  +----+----+----+----+-------------------------------------------------------+
  | S33| 0-2|5ASC|I19 | XOFF - This register contains the XOFF character used |
                        _______
  |    |    |    |    | when the modem is using XON/XOFF flow control.        |
  +----+----+----+----+-------------------------------------------------------+













                                                    Chapter 2.  S-Registers  45









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S36| N/A| -- | 7  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | LAPM FAILURE CONTROL - This register controls the way in which the   |
         _______________________
  |    | modem behaves if it is not able to establish an LAPM (V.42bis) error |
  |    | correcting link.  These fall back behaviors are executed immediately |
  |    | if the S48 register is set to 128.  Provides the following           |
  |    | functions:                                                           |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 111| LAPM failure behavior                                 |
  |    | 0-2|    |    | 000     disconnect                                    |
  |    |    |    |    | 001     Stay online and establish a direct connection |
  |    |    |    |    | 010     Reserved                                      |
  |    |    |    |    | 011     Stay online and establish a normal connection |
  |    |    |    |    | 100     Attempt MNP connection.  If the MNP           |
  |    |    |    |    | connection fails, disconnect.                         |
  |    |    |    |    | 101     Attempt MNP connection.  If the MNP           |
  |    |    |    |    | connection fails, establish a direct connection.      |
  |    |    |    |    | 110     Reserved                                      |
  |    |    |    |    | 111     Attempt MNP connection.  If the MNP           |
  |    |    |    |    | connection fails, establish a normal connection.      |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 3-7|    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+



























  46  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S37| N/A| -- | 0  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | LINE CONNECTION SPEED - If an invalid number is entered, the number  |
         ________________________
  |    | is accepted into the register, but S37 acts as if the default value  |
  |    | has been entered.  Provides the following functions:                 |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 000| Line connection speed                                 |
  |    | 0-4|    |    | 0000    Attempt automode connection (default)         |
  |    |    |    |    | 0001    Attempt to connect at 300 bps                 |
  |    |    |    |    | 0010    Attempt to connect at 300 bps                 |
  |    |    |    |    | 0011    Attempt to connect at 300 bps                 |
  |    |    |    |    | 0100    Reserved                                      |
  |    |    |    |    | 0101    Attempt to connect at 1200 bps/V.22           |
  |    |    |    |    | 0110    Attempt to connect at 2400 bps/V.22bis        |
  |    |    |    |    | 0111    Attempt to connect at V.23                    |
  |    |    |    |    | 1000    Attempt to connect at 4800 bps/V.32-V.32bis   |
  |    |    |    |    | 1001    Attempt to connect at 9600 bps/V.32-V.32bis   |
  |    |    |    |    | 1010    Attempt to connect at 1200 bps/V.32bis        |
  |    |    |    |    | 1011    Attempt to connect at 14 400 bps/V.32bis      |
  |    |    |    |    | 1100    Attempt to connect at 7200 bps/V.32bis        |
  |    |    |    |    | 1101    Reserved                                      |
  |    |    |    |    | 1110    Reserved                                      |
  |    |    |    |    | 1111    Reserved                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 5-7|    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+
  | S38| 0-2|5Sec|n20 | FORCED HANG UP - This register contains the delay, in |
                        _________________
  |    |    |    |    | seconds, between the time that the modem is issued a  |
  |    |    |    |    | disconnect command and the time that the modem        |
  |    |    |    |    | executes the disconnect operation.  This register is  |
  |    |    |    |    | active only if the modem is in error correcting mode. |
  +----+----+----+----+-------------------------------------------------------+


















                                                    Chapter 2.  S-Registers  47









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S39| N/A| -- | 3  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | FLOW CONTROL - This register controls the way in which the modem     |
         _______________
  |    | controls flow between itself and a remote modem.  See page 21 for    |
  |    | further information.  Provides the following functions:              |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 011| Flow control                                          |
  |    | 0-2|    |    | 000     None                                          |
  |    |    |    |    | 011     RTS/CTS ("AT&K3")                             |
  |    |    |    |    | 100     XON/XOFF ("AT&K4")                            |
  |    |    |    |    | 101     Transparent XON ("AT&K5")                     |
  |    |    |    |    | 110     Both RTS/CTS and XON/XOFF ("AT&K6")           |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 3-7|    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+
  | S40| N/A| -- | 105| Bit-mapped registers                                  |
  |    |    |    | (69|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | MNP ERROR CORRECTION CONTROLS - Provides the following functions:    |
         ________________________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 01 | MNP extended service                                  |
  |    | 0-1|    |    | 00 Disable extended services ("AT&K0)")               |
  |    |    |    |    | 01 Enable extended services ("AT&K1")                 |
  |    |    |    |    | 11 Enable extended services ("AT&K2")                 |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | MNP power level adjustment for cellular use           |
  |    | 2  |    |    | 0  Automatic adjustment ("M0")                        |
  |    |    |    |    | 1  Force adjustment ("M1")                            |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 101| Break handling                                        |
  |    | 3-5|    |    | 000     ("AT\K0")                                     |
  |    |    |    |    | 001     ("AT\K1")                                     |
  |    |    |    |    | 010     ("AT\K2")                                     |
  |    |    |    |    | 011     ("AT\K3")                                     |
  |    |    |    |    | 100     ("AT\K4")                                     |
  |    |    |    |    | 101     ("AT\K5")                                     |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 01 | MNP block size                                        |
  |    | 6, |    |    | 00 64 characters ("AT\A0")                            |
  |    | 7  |    |    | 01 128 characters ("AT\A1")                           |
  |    |    |    |    | 10 192 characters ("AT\A2")                           |
  |    |    |    |    | 11 256 characters ("AT\A3")                           |
  +----+----+----+----+-------------------------------------------------------+





  48  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S41| N/A| -- | 131| Bit-mapped registers                                  |
  |    |    |    | (83|)                                                      |
  |    +----+----+----+-------------------------------------------------------+
  |    | COMPRESSION CONTROLS - Provides the following functions:             |
         _______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 11 | MNP compression selection                             |
  |    | 0-1|    |    | 00 Disabled ("AT%C0")                                 |
  |    |    |    |    | 01 MNP5 ("AT%C1")                                     |
  |    |    |    |    | 10 V.42bis ("AT%C2")                                  |
  |    |    |    |    | 11 MNP5 and V.42bis ("AT%C3")                         |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 00 | Bit 62 Automatic retrain; fall back/fall forward      |
  |    | 2, |    |    |     00  Retrains; fall back/fall forward disabled     |
  |    | 6  |    |    | ("AT%E0")                                             |
  |    |    |    |    |     01  Retrains enabled ("AT%E1")                    |
  |    |    |    |    |     10  Fall back/fall forward enabled ("AT%E2")      |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Modem-to-modem flow control                           |
  |    | 3  |    |    | 0  Disabled ("AT%G0")                                 |
  |    |    |    |    | 1  Enabled ("AT%G1")                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Block mode control                                    |
  |    | 4  |    |    | 0  Stream mode ("AT\L0")                              |
  |    |    |    |    | 1  Block mode ("AT\L1")                               |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 5  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 1  | Fall back to V.22/V.22bis                             |
  |    | 7  |    |    | 0  Disabled ("ATQ0")                                  |
  |    |    |    |    | 1  Enabled ("ATQ1")                                   |
  |    +----+----+----+-------------------------------------------------------+
  +----+----+----+----+-------------------------------------------------------+
  | S46| -- | -- | 138| V.42BIS DATA COMPRESSION - This register controls the |
                        ___________________________
  |    |    |    |    | selection of V.42bis data compression.                |
  |    |    |    |    | 136     No data compression                           |
  |    |    |    |    | 138     Data compression                              |
  +----+----+----+----+-------------------------------------------------------+
  | S48| -- | -- |  7 | V.42BIS NEGOTIATION - This register controls the      |
                        ______________________
  |    |    |    |    | selection of V.42bis error correction.                |
  |    |    |    |    | 0  Force LAPM connection                              |
  |    |    |    |    | 7  Enable negotiation phase                           |
  |    |    |    |    | 128     Force to S36 (MNP/V.42)                       |
  +----+----+----+----+-------------------------------------------------------+
  | S82| -- | -- | -- | BREAK HANDLING OPTION -                               |
                        ________________________
  |    |    |    |    | NOTE - This register is included for compatibility    |
  |    |    |    |    | only.  The value programmed into this register has no |
  |    |    |    |    | effect on the modem's operation.                      |
  +----+----+----+----+-------------------------------------------------------+


                                                    Chapter 2.  S-Registers  49









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S86| -- | -- |  0 | CONNECTION FAILURE CODE -                             |
                        __________________________
  |    |    |    |    | Defined values include:                               |
  |    |    |    |    | 0  Normal disconnect                                  |
  |    |    |    |    | 4  Loss of carrier                                    |
  |    |    |    |    | 5  V.42 failure                                       |
  |    |    |    |    | 9  Modems could not find a common protocol            |
  |    |    |    |    | 12 Normal disconnect initiated by the remote modem    |
  |    |    |    |    | 13 Remote modem does not respond after 10             |
  |    |    |    |    | retransmissions of the same message.                  |
  |    |    |    |    | 14 Protocol failure                                   |
  |    |    |    |    | NOTE - This register holds the connection failure     |
  |    |    |    |    | cause code.  When the modem issues NO CARRIER, this   |
                                                           __________
  |    |    |    |    | register value tells why the modem disconnected the   |
  |    |    |    |    | line.  THIS IS A READ ONLY REGISTER.                  |
  +----+----+----+----+-------------------------------------------------------+
  | S95| N/A| -- | 0  | Bit-mapped registers                                  |
  |    +----+----+----+-------------------------------------------------------+
  |    | RESULT CODE CONTROL - Provides the following functions:              |
         ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | -- | Definition and Options                                |
         ___            ______________________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | CONNECT reporting                                     |
                        _______
  |    | 0  |    |    | 0  CONNECT reports DTE speed                          |
                           _______
  |    |    |    |    | 1  CONNECT reports DCE speed                          |
                           _______
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Append/ARQ to CONNECT XXXX result (Error correcting   |
                                      ____________
  |    | 1  |    |    | mode)                                                 |
  |    |    |    |    | 0  Do not append ARQ to CONNECT XXXX messages         |
                                                ____________
  |    |    |    |    | 1  Append ARQ to CONNECT XXXX messages                |
                                         ____________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | CARRIER XXXX result codes                             |
                        ____________
  |    | 2  |    |    | 0  Disable CARRIER XXXX result codes                  |
                                   ____________
  |    |    |    |    | 1  Enable CARRIER XXXX result codes                   |
                                  ____________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | PROTOCOL XXXX result codes                            |
                        _____________
  |    | 3  |    |    | 0  Disable PROTOCOL XXXX result codes                 |
                                   _____________
  |    |    |    |    | 1  Enable PROTOCOL XXXX result codes                  |
                                  _____________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 4  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | COMPRESSION result codes                              |
                        ___________
  |    | 5  |    |    | 0  Disable COMPRESSION result codes                   |
                                   ___________
  |    |    |    |    | 1  Enable COMPRESSION result codes                    |
                                  ___________
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 6  |    |    |                                                       |
  |    +----+----+----+-------------------------------------------------------+
  |    | Bit| -- | 0  | Reserved                                              |
  |    | 7  |    |    |                                                       |
  +----+----+----+----+-------------------------------------------------------+


  50  AT Commands









  +----+----+----+----+-------------------------------------------------------+
  | REG| RAN|EUNI|SDEF|UDESCRIPTION                                           |
  +----+----+----+----+-------------------------------------------------------+
  | S20| -- | -- | 32 | CELLULAR TRANSMIT LEVEL                               |
                        _______________________
  |    |    |    | (20|)0-4     Initial Cellular Power Level Setting          |
  |    |    |    |    | 5  Compromise Equalizer Enable Command                |
  |    |    |    |    | 6  Reserved                                           |
  |    |    |    |    | 7  Reserved                                           |
  +----+----+----+----+-------------------------------------------------------+















































                                                    Chapter 2.  S-Registers  51

































































  52  AT Commands









  CHAPTER 3.  MNP OPERATION
  _________________________





                      Microcom(**) Networking Protocol (MNP(**)) is a protocol
                      developed by Microcom for full-duplex, error-free
                      communications.  This protocol detects and corrects
                      errors that can result from telephone line noise and
                      other signal distortions.  There are several classes of
                      MNP operation (also referred to as service classes).
                      Class 5, for instance, maximizes data transfer rate and
                      provides compression that can significantly increase data
                      throughput.

                      IMPORTANT:  MNP can operate only at speeds of 2400 bps or
                      higher.


                      There are several levels of MNP operation available (also
                      referred to as service classes).  The modem supports
                      MNP2, 3, 4, and 5.




























  ---------------

  (**) Trademarks of Microcom Systems, Inc.


  (C) Copyright IBM Corp. 1995                                               53









                      These levels are summarized as follows:

                      MNP2      MNP2 uses an asynchronous, byte-oriented format
                                in which standard byte-framing techniques
                                (start and stop bits) and full-duplex
                                transmission are used.

                      MNP3      MNP3 uses a synchronous, bit-oriented format in
                                which standard byte-framing techniques are
                                removed.  This increases throughput by
                                approximately 20%.

                      MNP4      MNP4 optimizes performance by using more
                                efficient framing techniques and allowing for
                                transmission of large data blocks.  Data-block
                                size is adjusted based on the quality of the
                                telephone line (smaller for poor lines; larger
                                for higher quality lines).  This technique
                                reduces the number of retransmissions and
                                maximizes transfer rate based on the quality of
                                the phone line.

                      MNP5      MNP5 includes all the features of MNP4 and also
                                features data compression.  Both downloaded and
                                interactive real-time data are compressed.  A
                                significant increase on most data throughput
                                can be realized.  The "AT%C1" command enables
                                this class.  If MNP5 is disabled, the modem
                                defaults to MNP4.  MNP5 and MNP4 are not
                                compatible.


  MNP DATA MODE
  _____________

                      After establishing the MNP connection, the modem will
                      perform all functions performed during normal data mode
                      except:

                      o   When retrains are performed at 2400 bps operation or
                          higher, the modem might lose synchronization with the
                          incoming line signal.  Retraining is an adjustment
                          process performed when one of the modems detects
                          possible line problems that threaten data integrity.

                      o   When in the command mode following an escape
                          sequence, the modem will continue to acknowledge and
                          accept data.  This data is stored until the modem is
                          returned to data mode and then the data is delivered.
                          In non-MNP mode, any data received while the modem is
                          in command mode is lost.






  54  AT Commands









  MNP5 DATA COMPRESSION
  _____________________

                      MNP5 can be enabled or disabled by using the "AT%C"n
                                                                         _
                      command.  During an MNP5 connection, the modem compresses
                      data into tokens before transmitting to the remote modem,
                      and decompresses the data before it is received.


  PROGRAMMABLE INACTIVITY TIMER
  _____________________________

                      You can specify the length of time the modem will wait
                      before disconnecting when no data is sent or received.
                      In MNP mode, this timer is reset whenever data is sent or
                      received.  Use the "AT\T"n command to set this value,
                                               _
                      where n is a number between 0 and 42 minutes.
                            _


  DATA TRANSFER
  _____________

                      You can operate MNP in either block or stream mode.  In
                      stream mode, MNP sends data frames in varying lengths
                      depending on the amount of time between characters being
                      received.  Stream mode is selected with the "AT\L"n
                                                                        _
                      command.

                      In block mode, MNP sends fixed data frames of 64, 128,
                      192, or 256 characters in length.  Your communications
                      software must support the use of block mode.


  AT COMMANDS FOR MNP OPERATION
  _____________________________

                      The following AT commands apply to the MNP protocol.

                      \AN       Maximum MNP block size
                        _

                      \BN       Transmit break
                        _

                      \GN       Modem-to-modem flow control
                        _

                      \KN       Break control
                        _

                      \LN       MNP block transfer control
                        _

                      \NN       Error correction operating mode
                        _

                      Each of these commands is explained in the sections that
                      follow.








                                                  Chapter 3.  MNP Operation  55









                      COMMAND   DESCRIPTION

                      \An       MAXIMUM MNP BLOCK SIZE
                        _
                                Use this command to transmit smaller blocks of
                                data in a reliable data link connection.

                                Syntax:  "AT\A"n  ENTER
                                               _

                                n=0  Set maximum block size to 64 characters.
                                _

                                n=1  Set maximum block size to 128 characters
                                _
                                     (default).

                                n=2  Set maximum block size to 192 characters.
                                _

                                n=3  Set maximum block size to 256 characters.
                                _


                      \Bn       TRANSMIT BREAK
                        _
                                When this command is entered during a non-MNP
                                connection, a break signal is sent to the
                                remote modem.  The length of the break is 100
                                times the n parameter (1-9) in milliseconds.
                                          _
                                The default is 3.

                                Syntax:  "AT\B"n  ENTER
                                               _

                      \Gn       MODEM-TO-MODEM FLOW CONTROL
                        _
                                Enables or disables modem-to-modem flow control
                                during a normal mode connection.  This command
                                is ignored when error correction is selected.

                                Syntax:  "AT\G"n  ENTER
                                               _

                                n=0  Disables flow control (XON/XOFF)
                                _
                                     (default).

                                n=1  Enables flow control (XON/XOFF).
                                _


                      \Kn       BREAK CONTROL
                        _
                                Enables or disables modem-to-modem flow control
                                during a normal mode connection.  This command
                                is ignored when error correction is selected.

                                Syntax:  "AT\K"n  ENTER
                                               _

                                Determines the modem response when a break is
                                received from the DTE or the remote modem.

                                The values of the parameters vary based on the
                                three following conditions:




  56  AT Commands









                                o   When a break is received from the DTE
                                    during normal or MNP mode:

                                    n=0, 2, 4 Enters command mode without
                                    _
                                              sending a break to the remote
                                              modem.

                                    n=1       Clears the terminal and modem
                                    _
                                              buffers and sends a break to the
                                              remote modem.

                                    n=3       Does not clear the buffers, but
                                    _
                                              sends a break to the remote
                                              modem.

                                    n=5       Sends a break to the remote modem
                                    _
                                              in sequence with any transmitted
                                              data (default).

                                o   When a break is received from the remote
                                    modem during normal mode:

                                    n=0, 1    Clears the terminal and modem
                                    _
                                              buffers and sends a break to the
                                              local DTE.

                                    n=2, 3    Does not clear the buffers but
                                    _
                                              sends a break to the local DTE.

                                    n=4, 5    Sends a break in sequence with
                                    _
                                              any data being buffered
                                              (default).

                                o   When a break is received from the DTE
                                    during direct mode:

                                    n=0, 1    Clears the data buffers and sends
                                    _
                                              a break to the remote modem.

                                    n=2, 3    Immediately sends a break to the
                                    _
                                              remote modem.

                                    n=4, 5    Sends a break to the remote modem
                                    _
                                              in sequence with the data.












                                                  Chapter 3.  MNP Operation  57









                      \Ln       MNP BLOCK TRANSFER CONTROL
                        _
                                Determines whether the modem will use block or
                                stream mode for MNP link.

                                Syntax:  "AT\L"n  ENTER
                                               _

                                n=0  Uses stream mode for MNP link connections
                                _
                                     (default).

                                n=1  Uses block mode for MNP connections.
                                _


                      \Nn       ERROR CORRECTION OPERATING MODE
                        _
                                Selects the operating mode the modem uses while
                                it is connected.

                                Syntax:  "AT\N"n  ENTER
                                               _

                                n=0  Normal (speed buffering) mode.
                                _

                                n=1  Direct (pass-through) mode (default).
                                _

                                n=2  Reliable link mode.  Specifies error
                                _
                                     correction for the modem-to-modem
                                     connection.

                                n=3  Enters reliable link mode automatically.
                                _
                                     Attempts error-correction connection but
                                     will fall back to normal mode if unable to
                                     establish an MNP link.

                                n=4  LAPM error correction mode.
                                _

                                n=5  MNP error correction mode.
                                _


                      +FAE=n    DATA/FAX AUTO ANSWER
                           _
                                Allows the DTE to either restrict answering to
                                class 1 or to automatically detect whether the
                                calling station is a fax class 1 modem or data
                                modem, and answer accordingly.  This is a
                                service class 1 command.  The default for this
                                command is 0.

                                Syntax:  "+FAE="n  ENTER
                                                _

                                n=0  Disables data/fax auto answer mode.
                                _

                                n=1  Enables data/fax auto answer mode.
                                _







  58  AT Commands









                      +FCLASS=n SET CLASS SERVICE
                              _
                                This command must be issued before line
                                connection.  This is a service class 1 and
                                class 2 command.  The default for this command
                                is 0.

                                Syntax:  "+FCLASS="n  ENTER
                                                   _

                                n=0  Data modem
                                _

                                n=1  Select class 1 fax mode
                                _

                                n=2  Select class 2 fax mode
                                _


                      +<COMMAND>? QUERY CURRENT SERVICE CLASS
                                This command causes the modem to answer with
                                the current setting of the service class.  This
                                is a service class 1 and class 2 command.

                                Syntax:  "+<COMMAND>?"

                                n=0  Data mode
                                _

                                n=1  Fax class 1
                                _

                                n=2  Fax class 2
                                _


                      +<COMMAND>=? IDENTIFY FAX SERVICE CAPABILITY
                                This command determines the service class
                                available from the modem.

                                Syntax:  "+<COMMAND>=?"

                                +FAE=? 0 or 1
                                ______

                                +FCLASS=? 0, 1, or 2
                                _________


















                                                  Chapter 3.  MNP Operation  59

































































  60  AT Commands









  CHAPTER 4.  THE ITU-T STANDARD
  ______________________________





                      The protocols of the International Telecommunication
                      Union - Telecommunications (ITU-T) have evolved to
                      provide international standards.  These protocols,
                      commonly referred to as V-dot standards, are:

                      V.21      The ITU-T standard for 300 bps communications.
                                Domestic modems follow the Bell 103 standard,
                                but V.21 can accept international calls at 300
                                bps.

                      V.22      The ITU-T standard for 1200 bps communications.
                                The domestic equivalent is the Bell 212A
                                standard.

                      V.22BIS   The ITU-T standard for 2400 bps.

                      V.23      The ITU-T standard for 1200 bps with a 75 bps
                                back channel.  This standard is used mostly in
                                Europe and South America.

                      V.32      The ITU-T standard for 9600 bps and 4800 bps
                                communications.

                      V.32BIS   The ITU-T standard for an extensive class of
                                high-speed modems operating at 14 400 bps,
                                12 000 bps, 9600 bps, 7200 bps, and 4800 bps.

                      V.42      The ITU-T standard for detection and
                                negotiation for LAPM (Link Access Procedure for
                                Modems) error control. V.42 will also support
                                MNP levels 2-4.

                      V.42BIS   An extension of V.42, specifying the data
                                compression protocol for use with V.42.


  V.32 AND V.32BIS OPERATION
  __________________________

                      The V.32 and V.32bis protocols of the ITU-T allow for
                      high-speed data transmission and reception up to a
                      maximum throughput speed of 57 600 bps (with V.42bis data
                      compression).  Your 14 400 modem is upwardly compatible
                      to both of these high-speed modulation protocols.

                      The V.32 ITU-T standard enables full-duplex 9600 bps
                      asynchronous transmission to occur synchronously over the
                      switched telephone network and can attain throughput
                      rates of 38 400 bps when combined with V.42 error


  (C) Copyright IBM Corp. 1995                                               61









                      control.  The V.32bis modulation protocol extends the
                      9600 bps capability of V.32 to 14 400 bps while remaining
                      compatible with V.32 modems.

                      The remote modem must be capable of supporting V.32
                      protocols to communicate at these high speeds.

                      Possible modem-to-modem connection speeds are as follows:

                      +-------------+-----------------------------------------+
                      | V.32        | 4800 bps                                |
                      |             | 9600 bps                                |
                      +-------------+-----------------------------------------+
                      | V.32bis     | 14 400 bps                              |
                      |             | 12 000 bps                              |
                      |             | 7200 bps                                |
                      +-------------+-----------------------------------------+

                      The "ATN"n command (modulation handshake) determines
                               _
                      whether a modem allows only certain connections, or
                      automatically detects a remote modem's desired
                      connection.

                      o   The command "ATN1" (default) allows communicating at
                          any speed supported by both modems.

                      o   The command "ATN0" requires that the speed of the
                          connection be that specified by the value of
                          S-register 37.  If register S37 contains a value not
                          supported by V.32 protocol, no connection can be
                          made.


  V.42 AND V.42BIS ERROR CORRECTION
  _________________________________

                      V.42 and V.42bis are two communication protocol standards
                      set by ITU-T.

                      V.42 is the ITU-T standard for error correction in modems
                      and is normally found in modems that are 2400 bps or
                      faster.  V.42 supports LAPM and MNP4 and is therefore
                      compatible with modems using MNP4.

                      The V.42 specification is a standard that supports one of
                      the Microcom MNP2-4 error-correction protocols or the
                      LAPM error correction protocol.

                      The V.42bis specification is a data compression standard
                      that requires the LAPM error correction protocol.

                      MNP5 is another data compression standard that is not
                      compatible with V.42bis and is slower than the V.42bis
                      data compression standard.



  62  AT Commands









  DETECTION

                      Immediately after the initial handshake, the
                      communicating modems exchange a sequence of detection
                      patterns to verify that both sides support the error
                      correction technique.


  NEGOTIATION

                      The communicating modems exchange configuration
                      information.  If the detection phase fails, or
                      negotiation does not achieve the desired connection type,
                      a modem can do one of the following:

                      o   Hang up

                      o   Fall back to MNP

                      o   Fall back to a standard asynchronous mode



  AT COMMANDS FOR V.42
  ____________________

                      The following table lists AT commands that are used in
                      V.42 mode.

                      +--------+-----+----------------------------------------+
                      | COMMAND| VALU| RESULT                                 |
                      +--------+-----+----------------------------------------+
                      | "AT%Q" |     | Reports line signal quality.           |
                      +--------+-----+----------------------------------------+
                      | "AT%C"n| 0   | Disables data compression.             |
                              _
                      |        +-----+----------------------------------------+
                      |        | 1   | Enables MNP data compression.          |
                      |        +-----+----------------------------------------+
                      |        | 2   | Enables V.42bis data compression.      |
                      |        +-----+----------------------------------------+
                      |        | 3   | Enables both MNP and V.42 data         |
                      |        |     | compression (default).                 |
                      +--------+-----+----------------------------------------+














                                             Chapter 4.  The ITU-T Standard  63









                      +--------+-----+----------------------------------------+
                      | COMMAND| VALU| RESULT                                 |
                      +--------+-----+----------------------------------------+
                      | "AT%E"n| 0   | Disable line quality monitor and       |
                              _
                      |        |     | auto-retrain (default).                |
                      |        +-----+----------------------------------------+
                      |        | 1   | Enable line quality monitor and        |
                      |        |     | auto-retrain.                          |
                      |        +-----+----------------------------------------+
                      |        | 2   | Enable line quality monitor and        |
                      |        |     | fallback/fall forward.                 |
                      |        +-----+----------------------------------------+
                      |        | 3   | Enable line quality monitor and        |
                      |        |     | auto-retrain, but hang-up immediately  |
                      |        |     | when EQM reaches hang-up threshold     |
                      |        |     | (fast hang-up).                        |
                      +--------+-----+----------------------------------------+







































  64  AT Commands









  CHAPTER 5.  CELLULAR COMMANDS
  _____________________________





                      COMMAND   DESCRIPTION

                      &CARET.C2 DOWNLOAD CELLULAR PHONE DRIVER
                                Initiates the cellular phone driver download
                                function.  Upon receipt of the command, the
                                modem issues the OK message.  The user then
                                performs an ASCII download of the driver from
                                the host to the modem, typically using a
                                communications software package (with transmit
                                pacing turned off).

                                Syntax:  "&caret.C2" ENTER

                                Result codes:

                                OK       Cellular phone driver download
                                         completed successfully.

                                ERROR    Cellular phone driver download not
                                         completed successfully.  Checksum of
                                         record (in S37 file) is not correct,
                                         driver size is larger than 2KB or an
                                         incorrect driver is downloaded, or
                                         modem is connected.


                      &CARET.I  IDENTIFY CELLULAR PHONE DRIVER
                                The modem reports the identification of the
                                loaded cellular phone driver in response to the
                                &caret.I command.  The response is dependent
                                upon the driver.

                                Syntax:  "&caret.I" ENTER

                                Result codes (typical):

                                OK

                                ERROR    Cellular phone driver is not loaded.











  (C) Copyright IBM Corp. 1995                                               65









                      &CARET.T6 INDICATE STATUS OF CELLULAR PHONE
                                The status of the cellular phone connected to
                                the modem is reported in response to the
                                &caret.T6 command.  The status is reported by a
                                single byte formatted as a decimal number.  The
                                individual status signals assigned to the
                                status byte bits are:

                                bit 0  1= Cellular phone is receiving an
                                     incoming call.

                                bit 1  1= Cellular phone is in use.

                                bit 2  1= Cellular phone is locked (cannot be
                                     used).

                                bit 3  1= There is no service for cellular
                                     phone (does not indicate signal strength).

                                bit 4  1= Cellular phone is powered on.

                                bit 5  1= Cellular driver is initialized.

                                bit 6  0= Reserved (0)

                                bit 7  1= Cellular cable detected.

                                Syntax:  "&caret.T6" ENTER

                                Result codes (typical):

                                128      Cellular cable detected.

                                OK



  Application of &caret.T6 Status Byte

                                The information obtained by issuing an
                                AT&caret.T6 can be used to determine if the
                                loading of the cellular phone driver is
                                necessary by the host software.  A download is
                                not necessary if landline (or no cable) is
                                connected to the modem, in which &caret.T6 will
                                return a value of 0 (bit 7=0).  A download is
                                necessary when a cellular cable is detected
                                (implied cellular phone is also connected), in
                                which &caret.T6 will return a value of 128 (bit
                                7=1).  Once a driver is downloaded to the
                                modem, it will be able to operate in landline
                                or cellular mode based on detection of a
                                cellular cable.



  66  AT Commands








































































              IBM


              Part Number: 25H4231

              Printed in Canada

























































