
AT Command Reference Manual
for the RC96ATi and RC144ATi
Modem Families
(Preliminary)

This document is provided electronically for use for the express purpose of assisting software 
developers and end users answer frequently asked questions about Rockwell modem 
products.  
This manual ONLY describes the GENERIC Rockwell AT command set.  Modem vendors 
often change, add, and delete commands based on their particular product and feature set.  
Thus this document does not necessarily describe the AT commands used within your 
modem, even if it is based on Rockwell chipset products. Always consult your modem 
vendor's documentation first.
Rockwell International
Digital Communications Division
1994 Rockwell International	Order No. 891
All Rights Reserved	March 4, 1994
Printed in U.S.A.

NOTICE
Information furnished by Rockwell International Corporation is believed to be accurate and reliable. 
However, no responsibility is assumed by Rockwell International for its use, nor any infringement of 
patents or other rights of third parties which may result from its use. No license is granted by 
implication or otherwise under any patent rights of Rockwell International other than for circuitry 
embodied in Rockwell products. Rockwell International reserves the right to change circuitry at any 
time without notice. This document is subject to change without notice.


Hayes is a registered trademark of Hayes Microcomputer Products, Inc.


Table of Contents
1.	INTRODUCTION	1-1
1.1.	OVERVIEW	1-1
1.1.1.	Command Syntax	1-1
1.1.2.	Command Descriptions	1-1
1.1.3.	MCU Firmware Configuration	1-1
1.2.	REFERENCE DOCUMENTATION	1-1
2.	COMMAND SYNTAX	2-1
2.1.	DTE/DCE INTERCHANGE CIRCUITS	2-1
2.2.	COMMAND SYNTAX AND GUIDELINES	2-1
2.2.1.	DTE Commands	2-1
2.2.2.	DTE Command Lines	2-1
2.3.	AT COMMAND GUIDELINES	2-1
2.3.1.	Basic Command Syntax	2-1
2.3.2.	Extended Command Syntax	2-1
3.	AT COMMAND SET	3-1
3.1.	AT COMMAND GUIDELINES	3-1
3.1.1.	AT Commands, DTE Adaption	3-1
3.1.2.	AT Command Format	3-1
3.1.3.	Escape Code Sequence	3-1
3.2.	AT COMMAND SET	3-2
3.2.1.	AT Commands	3-2
A/ - Re-execute Command	3-2
AT= x - Write to Selected S-Register	3-2
AT? - Read Selected S-Register	3-2
A - Answer	3-2
Bn - CCITT or Bell	3-2
Cn - Carrier Control	3-3
Dn - Dial	3-3
En - Command Echo	3-4
Fn - Select Line Modulation	3-5
Hn - Disconnect (Hang-Up)	3-6
In - Identification	3-6
Ln - Speaker Volume	3-7
Mn - Speaker Control	3-7
Nn - Automode Enable	3-7
On - Return to On-Line Data Mode	3-7
P - Set Pulse Dial Default	3-8
Qn - Quiet Results Codes Control	3-8
Sn - Read/Write S-Register	3-8
T - Set Tone Dial Default	3-9
Vn - Result Code Form	3-9
Wn - Connect Message Control.	9
Xn - Extended Result Codes	3-10
Yn - Long Space Disconnect	3-12
Zn - Soft Reset and Restore Profile	3-12

Table of Contents (Continued)
3.2.2.	AT& Commands	3-13
&Cn - RLSD (DCD) Option	3-13
&Dn - DTR Option	3-13
&Fn - Restore Factory Configuration (Profile)	3-13
&Gn - Select Guard Tone	3-14
&Jn - Telephone Jack Control	3-14
&Kn - Flow Control	3-14
&Ln - Leased Line Command	3-14
&Mn - Asynchronous/Synchronous Mode Selection	3-15
&Pn - Select Pulse Dial Make/Break Ratio	3-15
&Qn - Sync/Async Mode	3-16
&Rn - RTS/CTS Option	3-16
&Sn - DSR Override	3-16
&Tn - Test and Diagnostics	3-17
&V - Display Current Configuration and Stored Profiles	3-18
&Wn - Store Current Configuration	3-18
&Xn - Select Synchronous Clock Source	3-19
&Yn - Designate a Default Reset Profile	3-19
&Zn=x - Store Telephone Number	3-19
3.2.3.	AT% Commands	3-19
%En - Enable/Disable Line Quality Monitor and Auto-Retrain or Fallback/Fall 
Forward	3-19
%L - Line Signal Level	3-20
%Q - Line Signal Quality	3-20
3.2.4.	AT\ Commands	3-20
\Gn - Modem-to-Modem Flow Control (XON/XOFF)	3-20
\Kn - Break Control	3-21
\Nn - Operating Mode	3-21
3.2.5.	AT+ Commands	3-22
+Hn - Enable/Disable RPI and DTE Speed	3-22
3.3.	AT COMMAND RESULT CODES	3-23
00- OK	3-23
01- CONNECT	3-23
02- RING	3-23
03- NO CARRIER	3-23
04- ERROR	3-23
05- CONNECT 1200	3-23
06- NO DIALTONE	3-23
07- BUSY	3-23
08- NO ANSWER	3-23
09- CONNECT 0600	3-24
10- CONNECT 2400	3-24
11- CONNECT 4800	3-24
12- CONNECT 9600	3-24
13- CONNECT 7200	3-24
14- CONNECT 12000	3-24
15- CONNECT 14400	3-24
16- CONNECT 19200	3-24
17- CONNECT 38400	3-24

Table of Contents (Continued)
18- CONNECT 57600	3-24
19- CONNECT 115200	3-24
22- CONNECT 75TX/1200RX	3-24
23- CONNECT 1200TX/75RX	3-24
33- FAX	3-24
35- DATA	3-25
40- CARRIER 300	3-25
44- CARRIER 1200/75	3-25
45- CARRIER 75/1200	3-25
46- CARRIER 1200	3-25
47- CARRIER 2400	3-25
48- CARRIER 4800	3-25
49- CARRIER 7200	3-25
50- CARRIER 9600	3-25
51- CARRIER 12000	3-25
52- CARRIER 14400	3-25
70- PROTOCOL: NONE	3-25
+FC- FCERROR	3-25
4.	S-REGISTERS	4-1
4.1.	FACTORY DEFAULTS	4-1
4.2.	S-REGISTER DEFINITIONS	4-3
S0 - Number of Rings to Auto-Answer	4-3
S1 - Ring Counter	4-3
S2 - Escape Character	4-3
S3 - Carriage Return Character	4-3
S4 - Line Feed Character	4-3
S5 - Backspace Character	4-3
S6 - Wait Time for Dial Tone Before Blind Dialing	4-4
S7 - Wait Time For Dial Tone After W Dial Modifier	4-4
S8 - Pause Time For Dial Delay	4-4
S9 - Carrier Detect Response Time	4-4
S10 - Lost Carrier To Hang Up Delay	4-4
S11 - DTMF Tone Duration	4-4
S12 - Escape Code Guard Time	4-4
S13 - Reserved	4-4
S14 - General Bit Mapped Options Status	4-5
S15 - Reserved	4-5
S16 - General Bit Mapped Test Options Status	4-6
S17 - Reserved	4-6
S18 - Test Timer	4-6
S19-S20 - Reserved	4-6
S21 - V.24/General Bit Mapped Options Status	4-7
S22 - Speaker/Results Bit Mapped Options Status	4-8
S23 - General Bit Mapped Options Status	4-9
S24 - Sleep Inactivity Timer	4-9
S25 - Delay To DTR	4-9
S26 - RTS to CTS Delay	4-9
S27 - Bit Mapped Options Status	4-10
S28 - Bit Mapped Options Status	4-11

Table of Contents (Continued)
S29 - Flash Dial Modifier Time	4-11
S30 - Disconnect Inactivity Timer	4-11
S31 - Bit Mapped Options Status	4-12
S32 - XON Character	4-12
S33 - XOFF Character	4-12
S34-S36 - Reserved	4-12
S37 - Desired Line Connection Speed	4-12
S38 - Reserved	4-13
S39 - Flow Control Bit Mapped Options Status	4-13
S40 - General Bit Mapped Options Status	4-13
S41 - General Bit Mapped Options Status	4-13
S91 - PSTN Transmit Attenuation Level	4-14
S92 - Fax Transmit Attenuation Level	4-14
S95 - Extended Result Codes	4-14
5.	FAX CLASS 1 COMMANDS	5-1
5.1.	FAX I/O PROCESSING	5-1
5.1.1.	DTE-to-Modem Transmit Data Stream	5-1
5.1.2.	Modem-to-DTE Receive Data Stream	5-1
5.1.3.	Fax Mode Selection	5-1
5.1.4.	Fax Origination	5-1
5.1.5.	Fax Answering	5-2
5.1.6.	Fax Control Transmission	5-2
5.1.7.	Fax Control Reception	5-2
5.1.8.	Fax Data Transmission	5-3
5.1.9.	Fax Data Reception	5-3
5.2.	COMMANDS	5-4
+FCLASS=n - Select Service Class	5-4
+F<command>? - Report Active Configuration	5-4
+F<command>=? - Report Operating Capabilities	5-4
+FAE=n - Data/Fax Auto Answer	5-4
+FTS=n - Stop Transmission and Wait	5-4
+FRS=n - Receive Silence	5-4
+FTM=n - Transmit Data	5-5
+FRM=n - Receive Data	5-5
+FTH=n - Transmit Data with HDLC Framing	5-6
+FRH=n - Receive Data with HDLC Framing	5-6
5.3.	EXAMPLES	5-6
A.	AT COMMAND SET SUMMARY	A-1
A.1.	BASIC AT COMMANDS	A-1
A.2.	FAX CLASS 1	A-3

List of Tables
Table 3-1.	Result Codes	3-11
Table 5-1.	Fax Class 1 Commands	5-1
Table 5-2.	Fax Class 1 Calling Sequence (One Page)	5-7
Table 5-3.	Fax Class 1 Answering Sequence (One Page)	5-8

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1.	INTRODUCTION
1.1.	OVERVIEW
This manual describes the AT commands for the RC96ATi and RC144ATi modem families:
The descriptions apply to all these modems with any differences between modem product families noted.
1.1.1.	Command Syntax
The fundamental DTE interface command syntax is described in Section 2.
1.1.2.	Command Descriptions
These commands are grouped into the following categories:
	AT commands	Section 3
	S-Registers	Section 4
	Fax Class 1 commands	Section 5
The AT commands are implemented in microcontroller (MCU) firmware for specific modem models. The support for a command 
category is identified by modem model in the modem designer's guide. Additional configuration and implementation information 
is available in release notes and/or readme files that accompany MCU firmware release.
1.2.	REFERENCE DOCUMENTATION
	Order No.	Description
	MD95	RC96ATi and RC144ATi Modem Data Sheet
	1031	RC96ATi and RC144ATi Modem Designer's Guide

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2.	COMMAND SYNTAX
2.1.	DTE/DCE INTERCHANGE CIRCUITS
Communication between the DTE and modem is half duplex (i.e., only one entity 'talks' at a time).
2.2.	COMMAND SYNTAX AND GUIDELINES
2.2.1.	DTE Commands
The ISO 646 character set (CCITT T.50 International Alphabet 5, American Standard Code for Information Interchange) is 
used for the issuance of commands and responses. Only the low-order 7 bits of each character are used for commands or 
parameters; the high-order bit is ignored. Upper case characters are equivalent to lower case characters.
2.2.2.	DTE Command Lines
A command line is a string of characters sent from a DTE to the DCE while the DCE is in a command state. Command lines 
have a prefix, a body, and a terminator. The prefix consists of the ASCII characters AT (065, 084) or at (097, 116). The 
body is a string of commands restricted to printable ASCII characters (032 - 126). Space characters (ASCII 032) and control 
characters other than carriage return <CR> (default value = ASCII 013 = 0Dh, see register S3), backspace <BS> (default value 
= ASCII 008 = 08h, see register S5), and cancel <cntrl-x> (ASCII 024 = 18h) in the command string are ignored. The default 
terminator is the <CR> character. Characters that precede the AT prefix are ignored.
2.3.	AT COMMAND GUIDELINES
Modem operation is controlled by generic AT commands. These AT commands may be basic AT (i.e., commands preceded by 
AT, AT&, AT%, or AT\), S-Register (e.g., S6=n), or Fax class 1 (e.g., +FTM)  commands. The command syntax and operation 
guidelines governing each of these command categories are described in subsequent sections.
2.3.1.	Basic Command Syntax
Characters within the command line are parsed as commands with associated parameter values. The basic commands consist 
of single ASCII characters, or single characters preceded by a prefix character, followed by a decimal parameter (e.g., &D1"). 
Missing decimal parameters are evaluated as 0. 
2.3.2.	Extended Command Syntax
The facsimile commands use extended syntax. They are preceded by the +F characters, and they are terminated by the 
semicolon : character (ASCII 059) or by the <CR> that terminates the command line.

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3.	AT COMMAND SET
3.1.	AT COMMAND GUIDELINES
The basic AT commands used to control modem operation are defined in this section. These commands are summarized in 
Appendix A. All these commands may not be available in a specific product depending upon supported data rates and modes. 
The default values are typical of a fully configured modem supporting all data rates and options. The actual default value is 
dependent upon modem firmware as defined by the firmware release notes. 
3.1.1.	AT Commands, DTE Adaption
Under AT operation, the serial interfaced modem performs an autobaud/autoparity/autolength function on each AT header 
entered. The autolength/autoparity facility can detect 7- or 8-bit characters of even, odd, or no parity with one stop bit. This is 
not necessary for the parallel interfaced modem since it has direct access to the UART registers.
3.1.2.	AT Command Format
Each command line (with the exception of the A/ command) must begin with the character sequence AT and must be 
terminated by a carriage return. The command line interpretation begins upon receipt of the carriage return character.
The modem supports the editing of command lines by recognizing a backspace character. When modem echo is enabled, the 
modem responds to receipt of a backspace or delete by echoing a backspace character, a space character, and another 
backspace. The hex value to be used for the backspace character is programmable through register S5. Values equal to 0 or 
greater than 127, or the value which corresponds to the carriage return character, cannot be used for the backspace 
character. This editing is not applicable to the AT header of a command. A command line may be aborted at any time by 
entering < cntrl-x > (18h).
The AT sequence may be followed by any number of commands in sequence, except for commands such as Z, D, or A. 
Commands following commands Z, D, or A on the same command line will be ignored. The maximum number of characters on 
any command line is 39 (including "A" and "T"). If a syntax error is found anywhere in a command line command, the remainder 
of the line will be ignored and the ERROR result code will be returned.
Most commands entered with parameters out of range will not be accepted and the ERROR response will be returned to the 
DTE.
Commands will only be accepted by the modem once the previous command has been fully executed, which is normally 
indicated by the return of an appropriate result code. Execution of commands D and A, either as a result of a direct command 
or a re-execute command, will be aborted if another character is entered before completion of the handshake.
3.1.3.	Escape Code Sequence
When the modem has established a connection and has entered on-line data mode, it is possible to break into the data 
transmission in order to issue further commands to the modem in an on-line command mode. This is achieved by the DTE 
sending to the modem a sequence of three ASCII characters specified by register S2. The default character is '+'. The timing 
of the three characters must comply with specific time constraints. There is a guard time before the first character (the pre-
sequence time), a guard time following the third character (the post-sequence time), and a guard time-out between the first 
and second characters and between the second and third characters (the inter-character time). These times are controlled by 
the value recorded in register S12.

3.2.	AT COMMAND SET
The modem will respond to the commands detailed below. Parameters applicable to each command are listed with the 
command description. The defaults shown for each configuration command are those used in the Rockwell factory profile0.
3.2.1.	AT Commands
A/ - Re-execute Command
The modem behaves as though the last command line had been re-sent by the DTE. "A/" will repeat all the commands in the 
command buffer.
The principal application of this command is to place another call (using the Dial command) that failed to connect due to a busy 
line, no answer, or a wrong number. This command must appear alone on a command line. This command should not be 
terminated by a carriage return.
AT= x - Write to Selected S-Register
This command writes the value x to the currently selected S-Register. An S-Register can be selected by using the ATSn 
command. All of the S-Registers will return the OK response if x is a number.
Result Codes
OK	For all arguments.
AT? - Read Selected S-Register
This command reads and displays the selected S-Register. An S-Register can be selected by using the ATSn command.
Result Codes:
OK	For all arguments.
A - Answer
The modem will go off-hook and attempt to answer an incoming call if correct conditions are met. Upon successful completion 
of answer handshake, the modem will go on-line in answer mode. Operation is also dependent upon +FCLASS command.
If +FCLASS=0 is selected, the modem will enter the connect state after exchanging carrier with the remote modem. If no 
carrier is detected within a period specified in register S7, the modem hangs up. Any character entered during the connect 
sequence will abort the connection attempt.
If +FCLASS=1 is selected, the modem will go off-hook in V.21 answer mode. It will generate the V.21 2100 Hz answer tone for 3 
 0.5 seconds and, following a delay of 70 ms, will proceed as if the +FTH=3 command were issued. At any stage up to (but 
excluding) the +FTH=3 command state, any character will abort the communication. (See the description of the +FTH 
command for details.)
Bn - CCITT or Bell
When the modem is configured to allow either option, the modem will select Bell or CCITT modulation for a line speed 
connection of 300 or 1200 bps according to the parameter supplied. Any other line speed will use a CCITT modulation 
standard. The parameter value, if valid, is written to S27 bit 6. (Also, see ATFn command.)
B0	Selects CCITT operation at 300 or 1200 bps during Call Establishment and a subsequent 
connection.
B1	Selects BELL operation at 300 or 1200 bps during Call Establishment and a subsequent 
connection. (Default.)
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

Cn - Carrier Control
This command is included for compatibility only, and has no effect other than returning a result code. The only valid parameter 
is 1.
Result Codes:
OK	n = 1.
ERROR	Otherwise.
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.
If +FCLASS=0, the modem will behave as a data modem and will attempt to connect to another data modem. The modem will 
have up to the period of time specified by register S6 or S7 to wait for carrier and complete the handshake. If this time expires 
before the modem can complete the handshake, the modem will go on-hook with the NO CARRIER response. This command 
will be aborted in progress upon receipt of any DTE character before completion of the handshake.
If +FCLASS=1, the modem will behave as a facsimile modem and attempt to connect to a facsimile machine (or modem) by 
entering the HDLC V.21 channel 2 receive state (as if +FRH=3 had been issued). This command will be aborted upon receipt of 
any DTE character if the modem has not finished dialing. In this case, the modem will go on-hook and return to command mode 
after displaying the NO CARRIER message. If the modem has finished dialing, it proceeds as if the +FRH=3 command has 
been issued. (Refer to the +FRH command to determine how the modem behaves following this stage.)
Dial Modifiers. The valid dial string parameters are described below. Punctuation characters may be used for clarity, with 
parentheses, hyphen, and spaces being ignored.
0-9	DTMF digits 0 to 9.
*	The 'star' digit (tone dialing only).
#	The 'gate' digit (tone dialing only).
A-D	DTMF digits A, B, C, and D.
L	Re-dial last number: the modem will re-dial the last valid telephone number. The L must be immediately 
after the D with all the following characters ignored).
P	Select pulse dialing: pulse dial the numbers that follow until a "T" is encountered. Affects current and 
subsequent dialing.
T	Select tone dialing: tone dial the numbers that follow until a "P" is encountered. Affects current and 
subsequent dialing. Some countries prevent changing dialing modes after the first digit is dialed.
R	This command will be accepted, but not acted on.
S=n	Dial the number stored in the directory (n = 0 to 3). (See &Zn.)
!	Flash: the modem will go on-hook for a time defined by the value of S29.
W	Wait for dial tone: the modem will wait for dial tone before dialing the digits following "W". If dial tone is 
not detected within the time specified by S7, the modem will abort the rest of the sequence, return on-
hook, and generate an error message.
@	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. If the modem does not detect these 5 
seconds of silence before the expiration of the call abort timer (S7), the modem will terminate the call 
attempt with a NO ANSWER message. If busy detection is enabled, the modem may terminate the call 
with the BUSY result code. If answer tone arrives during execution of this parameter, the modem 
handshakes.
&	Wait for AT&T "bong" tone for credit card dialing before continuing with the dial string. If bong is not 
detected within the time specified by S7, the modem will abort the rest of the sequence, return on-
hook, and generate an error message.
,	Dial pause: the modem will pause for a time specified by S8 before dialing the digits following ",".
;	Return to command state. Added to the end of a dial string, this causes the modem to return to the 
command state after it processes the portion of the dial string preceding the ";". This allows the user 
to issue additional AT commands while remaining off-hook. The additional AT commands may be 
placed in the original command line following the ";" and/or may be entered on subsequent command 
lines. The modem will enter call progress only after an additional dial command is issued without the 
";" terminator. Use "H" to abort the dial in progress, and go back on-hook.
^	Toggles calling tone enable/disable: applicable to current dial attempt only.
( )	Ignored: may be used to format the dial string.
-	Ignored: may be used to format the dial string.
<space>	Ignored: may be used to format the dial string.
<i>	Invalid character: will be ignored.
En - Command Echo
The modem enables or disables the echo of characters to the DTE according to the parameter supplied. The parameter value, 
if valid, is written to S14 bit 1.
E0	Disables command echo.
E1	Enables command echo. (Default.)
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

Fn - Select Line Modulation
This command selects the line modulation according to the parameter supplied. The line modulation is fixed unless Automode 
is selected. This command interacts with the S37 and the N command. The parameter value, if valid, is written to S37 bits 0-4. 
To select line modulation, it is recommended that either the F command, or a combination of the S37 and the N command, be 
used, but not both. 
F0	Selects auto-detect mode. Sets N1 and sets S31 bit 1. In this mode, the modem configures for 
Automode operation. All connect speeds supported by the modem are possible according to the 
remote modem's preference. The contents of S37 are ignored as is the sensed DTE speed.
F1	Selects V.21 or Bell 103 according to the B setting as the only acceptable line speed resulting in a 
subsequent connection. Sets N0, sets S37 to 1, and clears S31 bit 1. This command is equivalent 
to the command string: ATN0S37=1.
F2	Not supported. 
F3	Selects V.23 as the only acceptable line modulation for a subsequent connection. Originator is at 
75 bps and answerer is at 1200 bps. Sets N0, sets S37 to 7, and clears S31 bit 1. This command is 
equivalent to the command string: ATN0S37=7.
F4	Selects V.22 1200 or Bell 212A according to the B command setting as the only acceptable line 
speed for a subsequent connection. Sets N0, sets S37 to 5, and clears S31 bit 1. This command is 
equivalent to the command string: ATN0S37=5.
F5	Selects V.22 bis as the only acceptable line modulation for a subsequent connection. Sets N0, 
sets S37 to 6, and clears S31 bit 1. This command is equivalent to the command string: 
ATN0S37=6.
F6	Select V.32 bis 4800 or V.32 4800 as the only acceptable line modulation for a subsequent 
connection. Sets N0, sets S37 to 8, and clears S31 bit 1. This command is equivalent to the 
command string: ATN0S37=8.
F7	Selects V.32 bis 7200 as the only acceptable line modulation for a subsequent connection. Sets 
N0, sets S37 to 12, and clears S31 bit 1. This command is equivalent to the command string: 
ATN0S37=12.
	This setting also allows connection at the Rockwell proprietary 7200 V.32 speed, e.g., with a 
RC9696/12 based modem.
F8	Selects V.32 bis 9600 or V.32 9600 as the only acceptable line modulations for a subsequent 
connection. Sets N0, sets S37 to 9, and clears S31 bit 1. This command is equivalent to the 
command string: ATN0S37=9.
F9	Selects V.32 bis 12000 as the only acceptable line modulation for a subsequent connection. Sets 
N0, sets S37 to 10, and clears S31 bit 1. This command is equivalent to the command string: 
ATN0S37=10.
	This setting also allows connection at the Rockwell proprietary 12000 V.32 speed, e.g., with a 
RC9696/12 based modem.
F10	Selects V.32 bis 14400 as the only acceptable line modulation for a subsequent connection. Sets 
N0, sets S37 to 11, and clears S31 bit 1. This command is equivalent to the command string: 
ATN0S37=11.

Hn - Disconnect (Hang-Up)
This command initiates a hang up sequence.
H0	The modem will release the line if the modem is currently on-line, and will terminate any test (AT&T) 
that is in progress. 
H1	If on-hook, the modem will go off-hook and enter command mode. 
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
In - Identification
The modem reports to the DTE the requested result according to the command parameter.
I0	Reports product code (e.g., "14400").
I1	Reports a precomputed checksum (see firmware release notes).
I2	Reports "OK".
I3	Reports firmware revision (VX.XXX)-model code (A = 64K US, C = 128K US), interface type (S = 
serial; P = parallel), and MCU model (39 = C39) (e.g., "V1.297-CS29").
I4	Reports OEM defined identifier string (e.g., "RC96ATi") in either Hayes-compatible binary format.
I5	Reports Country Code parameter (e.g., "022").
I6	Reports modem data pump model and internal code revision (e.g, RC144DPi Rev CE).
Result Codes:
OK	n = 0 to 6.
ERROR	Otherwise.

Ln - Speaker Volume
The modem sets the speaker volume control according to the parameter supplied. The parameter value, if valid, is written to 
S22 bits 0 and 1.
L0	Low volume.
L1	Low volume. (Default.)
L2	Medium volume.
L3	High volume.
Result Codes:
OK	n = 0 to 3.
ERROR	Otherwise.
Mn - Speaker Control
This command selects when the speaker will be on or off. The parameter value, if valid, is written to S22 bits 2 and 3.
M0	Speaker is always off.
M1	Speaker is on during call establishment, but off when receiving carrier. (Default.)
M2	Speaker is always on.
M3	Speaker is off when receiving carrier and during dialing, but on during answering.
Result Codes:
OK	n = 0 to 3.
ERROR	Otherwise.
Nn - Automode Enable
This command enables or disables Automode detection. The parameter value, if valid, is written to S31 bit 1.
N0	Automode detection is disabled. A subsequent handshake will be conducted according to the 
contents of S37 or, if S37 is zero, according to the most recently sensed DTE speed.
N1	Automode detection is enabled. A subsequent handshake will be conducted according to the 
Automode algorithm supported by the modem. This command is equivalent to F0. (Default.)
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
On - Return to On-Line Data Mode
This command determines how the modem will enter the on-line data mode. If the modem is in the on-line command mode, the 
enters the on-line data mode with or without a retrain. If the modem is in the off-line command mode (no connection), ERROR is 
reported.
O0	Enters on-line data mode without a retrain. Handling is determined by the Call Establishment task. 
Generally, if a connection exists, this command connects the DTE back to the remote modem after 
an escape (+++).
O1	Enters on-line data mode with a retrain before returning to on-line data mode.
Result Codes:
OK	n = 0 or 1 and a connection exists.
ERROR	Otherwise or if not connected.

P - Set Pulse Dial Default
This command forces pulse dialing until the next T dial modifier or T command is received. Sets S14 bit 5.
As soon as a dial command is executed which explicitly specifies the dialing mode for that particular call (e.g., ATDT...), this 
command is overridden so that all future dialing will be tone dialed. (See T command.)
Result Code:
OK
Qn - Quiet Results Codes Control
The command enables or disables the sending of result codes to the DTE according to the parameter supplied. The parameter 
value, if valid, is written to S14 bit 2.
Q0	Enables result codes to the DTE. (Default.)
Q1	Disables result codes to the DTE.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
Sn - Read/Write S-Register
The modem selects an S-Register, performs an S-Register read or write function, or reports the value of an S-Register.
n	Establishes S-Register n as the last register accessed.
n=v	Sets S-Register n to the value v.
n?	Reports the value of S-Register n.
The parameter n can be omitted, in which case the last S-Register accessed will be assumed. The S can be omitted for AT= 
and AT?, in which case the last S-Register accessed will be assumed.
For example:
	ATS7 establishes S7 as the last accessed register.
	AT=40 sets the contents of the last register accessed to 40.
	ATS=20 sets the contents of the last register accessed to 20.
If the number "n" is beyond the range of the S-Registers available, the modem will return the ERROR message. The value "v" is 
"MOD"ed with 256. If the result is outside the range permitted for a given S-Register the values will still be stored, but 
functionally the lower and higher limits will be observed. Input and output are always in decimal format. Note that some S-
Registers are read-only.
In some cases, writing to the S-Register will appear to be accepted but the value will not actually be written.

T - Set Tone Dial Default
This command forces DTMF dialing until the next P dial modifier or P command is received. The modem will set an S-Register 
bit to indicate that all subsequent dialing should be conducted in tone mode. Note that the DP command will override this 
command. Clears S14 bit 5.
Result Code:
OK
Vn - Result Code Form
This command selects the sending of short-form or long-form result codes to the DTE. The parameter, if valid, is written to S14 
bit 3.
V0	Enables short-form (terse) result codes. Line feed is not issued before a short-form result code.
V1	Enables long-form (verbose) result codes. (Default.)
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
Wn - Connect Message Control.
This command controls the format of CONNECT messages. The parameter value, if valid, is written to S31 bits 2 and 3. Note 
that the Wn command can be overridden by register S95 bits (see S95 description).
W0	Upon connection, the modem reports only the DTE speed (e.g., CONNECT 19200). Subsequent 
responses are disabled. (Default.)
W1	Upon connection, the modem reports the line speed, PROTOCOL NONE, and the DTE speed, 
respectively. Subsequent responses are disabled.
W2	Upon connection, the modem reports the DCE speed (e.g., CONNECT 14400). Subsequent 
responses are disabled.
Result Codes:
OK	n = 0, 1, or 2.
ERROR	Otherwise.

Xn - Extended Result Codes
This command selects which subset of the result messages will be used by the modem to inform the DTE of the results of 
commands.
If the user wishes to enforce dial tone detection, a "W" can be placed in the dial string (see D command). Note that the 
information below is based upon the default implementation of the X results table. Table 3-1 indicates the messages which are 
enabled for each X value.
If the modem is in facsimile mode (+FCLASS=1), the only message sent to indicate a connection is CONNECT without a speed 
indication.
X0	Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, and 
NO ANSWER result codes. If busy tone detection is enforced and busy tone is detected, NO 
CARRIER will be reported. If dial tone detection is enforced or selected and dial tone is not 
detected, NO CARRIER will be reported instead of NO DIAL TONE. The value 000b is written to S22 
bits 6, 5, and 4, respectively.
X1	Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO 
ANSWER, and CONNECT XXXX (XXXX = rate). Blind dialing enabled/disabled by country 
parameters. If busy tone detection is enforced and busy tone is detected, NO CARRIER will be 
reported instead of BUSY. If dial tone detection is enforced or selected and dial tone is not 
detected, NO CARRIER will be reported instead of NO DIAL TONE. The value 100b is written to S22 
bits 6, 5, and 4, respectively.
X2	Disables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO 
DIALTONE, NO ANSWER, and CONNECT XXXX. If busy tone detection is enforced and busy tone 
is detected, NO CARRIER will be reported instead of BUSY. If dial tone detection is enforced or 
selected and dial tone is not detected, NO DIAL TONE will be reported instead of NO CARRIER. The 
value 101b is written to S22 bits 6, 5, and 4, respectively.
X3	Enables monitoring of busy tones; send only OK, CONNECT, RING, NO CARRIER, ERROR, NO 
ANSWER, and CONNECT XXXX. If dial tone detection is enforced and dial tone is not detected, NO 
CARRIER will be reported. The value 110b is written to S22 bits 6, 5, and 4, respectively.
X4	Enables monitoring of busy tones; send all messages. The value 111b is written to S22 bits 6, 5, 
and 4, respectively. (Default.)
Result Codes:
OK	n = 0 to 4.
ERROR	Otherwise.

Table 3-1.  Result Codes
Short Form	Long Form	 n Value in ATXn Command				
		0	1	2	3	4
0	OK	x	x	x 	x 	x 
1	CONNECT	x	x 	x 	x	x
2	RING 	x	x 	x 	x	x
3	NO CARRIER 	x	x 	x 	x	x
4	ERROR	x	x 	x 	x	x
5	CONNECT 1200 	1	x	x	x	x
6	NO DIALTONE 	3	3 	x 	x 	x
7	BUSY 	3	3	3	x	x
8	NO ANSWER 	x 	x	x 	x	x
9	CONNECT 0600 	1 	x	x	x	x
10	CONNECT 2400 	1	x	x	x	x
11	CONNECT 4800	1	x	x	x	x
12	CONNECT 9600	1	x	x	x	x
13	CONNECT 7200	1	x	x	x	x
14	CONNECT 12000	1	x	x	x	x
15	CONNECT 14400	1	x	x	x	x
16	CONNECT 19200	1	x	x	x	x
17	CONNECT 38400	1	x	x	x	x
18	CONNECT 57600	1	x	x	x	x
22	CONNECT 75TX/1200RX	1	x	x	x	x
23	CONNECT 1200TX/75RX	1	x	x	x	x
33	FAX	x	x	x 	x	x
35	DATA	x	x	x 	x	x
40	CARRIER 300	x	x	x 	x	x
44	CARRIER 1200/75	x	x	x 	x	x
45	CARRIER 75/1200	x	x	x 	x	x
46	CARRIER 1200	x	x	x 	x	x
47	CARRIER 2400	x	x	x 	x	x
48	CARRIER 4800	x	x	x 	x	x
49	CARRIER 7200	x	x	x 	x	x
50	CARRIER 9600	x	x	x 	x	x
51	CARRIER 12000	x	x	x 	x	x
52	CARRIER 14400	x	x	x 	x	x
+F4	+FCERROR	x	x	x 	x	x
Note: An 'X' in a column indicates that the message (either the long form if verbose, or the
value only for short form) will be generated when that particular value of 'n' (shown at the top of
the column) has been selected by the use of ATXn. If the column is blank, then no message will
be generated for that X option. A numeral indicates which less explicit message (verbose or
short form) will be output for that X option. (Also, see Section 3.3).						

Yn - Long Space Disconnect
This command enables/disables the generation and response to long space disconnect. The parameter value, if valid, is 
written to S21 bit 7.
Y0	Disables long space disconnect. (default.)
Y1	Enables long space disconnect. The modem will send a long space of four seconds prior to going 
on-hook. 
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
Zn - Soft Reset and Restore Profile
The modem performs a soft reset and restores (recalls) the configuration profile according to the parameter supplied. If no 
parameter is specified, zero is assumed.
Z0	Soft reset and restore stored profile 0.
Z1	Soft reset and restore stored profile 1.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

3.2.2.	AT& Commands
&Cn - RLSD (DCD) Option
The modem controls the RLSD output in accordance with the parameter supplied. The parameter value, if valid, is written to 
S21 bit 5.
&C0	RLSD remains ON at all times. (Default.)
&C1	RLSD follows the state of the carrier.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
&Dn - DTR Option
This command interprets the ON to OFF transition of the DTR signal from the DTE in accordance with the parameter supplied. 
The parameter value, if valid, is written to S21 bits 3 and 4.
&D0 -	DTR drop is interpreted according to the current &Q setting as follows: (Default.)
&Q0, &Q6	DTR is ignored (assumed ON). Allows operation with DTEs which don't 
provide DTR.
&Q1	DTR drop causes the modem to hang up. Auto-answer is not affected.
&Q2, &Q3	DTR drop causes the modem to hang up. Auto-answer is inhibited.
&D1	DTR drop is interpreted according to the current &Q setting as follows:
&Q0, &Q1, &Q6	DTR drop is interpreted by the modem as if the asynchronous escape 
sequence had been entered. The modem returns to asynchronous 
command state without disconnecting.
&Q2, &Q3	DTR drop causes the modem to hang up. Auto-answer is inhibited.
&D2	DTR drop is interpreted according to the current &Q setting as follows:
&Q0, &Q1, &Q6	DTR drop causes the modem to hang up. Auto-answer is inhibited.
&D3	DTR drop is interpreted according to the current &Q setting as follows:
&Q0, &Q1, &Q6	DTR drop causes the modem to perform a soft reset as if the Z command 
were received. The &Y setting determines which profile is loaded.
&Q2, &Q3	DTR drop causes the modem to hang up. Auto-answer is inhibited.
If &Q6 or +FCLASS=1 is in effect, the action taken is the same as for &Q0.
&Fn - Restore Factory Configuration (Profile)
The modem loads the factory default configuration (profile). The factory defaults are identified for each command and in the S-
Register descriptions. A configuration (profile) consists of a subset of S-Registers.
&F0	Restore factory configuration 0.
&F1	Restore factory configuration 1.
Result Codes:
OK	
ERROR	If the modem is connected.

&Gn - Select Guard Tone
The modem generates the guard tone selected by this command according to the parameter supplied (DPSK modulation 
modes only). The parameter value, if valid, is written to S23 bits 6 and 7.
&G0	Disables guard tone. (Default.)
&G1	Disables guard tone.
&G2	Selects 1800 Hz guard tone.
Result Codes:
OK	n = 0 to 2.
ERROR	Otherwise.
&Jn - Telephone Jack Control
This command is only included for compatibility and performs no function except to load the S-Register. The parameter value, 
if valid, is written S21 bit 1.
&J0	&J0 command. (Default.)
&J1	&J1 command.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
&Kn - Flow Control
This command defines the DTE/DCE (terminal/modem) flow control mechanism. The parameter value, if valid, is written to S39 
bits 0, 1, and 2.
&K0	Disables flow control.
&K3	Enables RTS/CTS flow control. (Default for data modem modes.)
&K4	Enables XON/XOFF flow control.
&K5 	Enables transparent XON/XOFF flow control.
&K6 	Enables both RTS/CTS and XON/XOFF flow control. (Default for fax modem modes.)
Result Codes:
OK	n = 0, 3, 4, 5, or 6.
ERROR	Otherwise.
&Ln - Leased Line Command
This command requests leased or dial-up line operation. This command is provided for compatibility only; no mode change is 
performed, dial-up operation continues. The OK response is returned for a valid parameter, but no other action is performed. 
The parameter value, if valid, is written to S27 bit 2.
&L0	Requests dial-up operation. Dial-up operation continues. 
&L1	Requests leased line operation. Dial-up operation continues.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

&Mn - Asynchronous/Synchronous Mode Selection
This command determines the DTR operating mode. The modem treats the &M command as a subset of the &Q command.
&M0	Selects direct asynchronous operation. Note that the command sequence &M0\N0 selects normal 
buffered mode, but the command sequence \N0&M0 selects direct mode. This is because the \N0 
command is analogous to the &Q6 command. The value 000b is written to S27 bits 3, 1, and 0, 
respectively. (See &Q).
&M1	Selects synchronous connect mode with async off-line command mode. The value 001b is written 
to S27 bits 3, 1, and 0, respectively. (Serial interface operation only.)
&M2	Selects synchronous connect mode with async off-line command mode. Same as &M1 except that 
&M2 enables DTR dialing of directory slot 0. The modem will disconnect if DTR is OFF for more than 
the period in S25 (in units of hundredths of a second): the data connection will be synchronous. 
The value 010b is written to S27 bits 3, 1, and 0, respectively. (Serial interface operation only.)
&M3	Selects synchronous connect mode. This mode allows DTR to act as a talk/data switch. The call is 
manually initiated while DTR is inactive. When DTR becomes active, the handshake proceeds in 
originate or answer mode according to S14 bit 7. The value 011b is written to S27 bits 3, 1, and 0, 
respectively. (Serial interface operation only.)
Result Codes:
OK	n = 0 to 3.
ERROR	Otherwise.
&Pn - Select Pulse Dial Make/Break Ratio
This command determines the make/break ratio used during pulse dialing. The parameter value, if valid, is written to S28 bits 3 
and 4.
&P0	Selects 39%-61% make/break ratio at 10 pulses per second. (Default.)
&P1	Selects 33%-67% make/break ratio at 10 pulses per second.
Result Codes:
OK	n = 0 to 3.
ERROR	Otherwise.

&Qn - Sync/Async Mode
This command is an extension of the &M command and is used to control the connection modes permitted. It is used in 
conjunction with S36 and S48. (Also, see \N.) 
NOTE: When the &Q0 to &Q3 command is issued to select the mode, the subsequent connect message will report the DCE 
speed regardless of the W command and S95 settings.
&Q0	Selects direct asynchronous operation. The value 000b is written to S27 bits 3, 1, and 0, 
respectively. See &M0.
&Q1	Selects synchronous connect mode with async off-line command mode. The value 001b is written 
to S27 bits 3, 1, and 0, respectively. See &M1. (Serial interface operation only.)
&Q2	Selects synchronous connect mode with async off-line command modeand enables DTR dialing of 
directory 0. The value 010b is written to S27 bits 3, 1, and 0, respectively. See &M2. (Serial 
interface operation only.)
&Q3	Selects synchronous connect mode with async off-line command mode and enables DTR to act as 
Talk/Data switch. The value 011b is written to S27 bits 3, 1, and 0, respectively. See &M3. (Serial 
interface operation only.)
&Q4	Reserved.
&Q5	Reserved.
&Q6	Selects asynchronous operation in normal mode (speed buffering). The value 110b is written to S27 
bits 3, 1, and 0, respectively.
Result Codes:
OK	n = 0 to 6.
ERROR	Otherwise.
&Rn - RTS/CTS Option
This selects how the modem controls CTS. CTS operation is modified if hardware flow control is selected (see &K command). 
The parameter value, if valid, is written to S21 bit 2.
&R0	In sync mode, CTS tracks the state of RTS; the RTS-to-CTS delay is defined by S26. 
&R1	In sync mode, CTS is always ON (RTS transitions are ignored). In async mode, CTS will only drop if 
required by flow control. (Default.)
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.
&Sn - DSR Override
This command selects how the modem will control DSR. The parameter value, if valid, is written to S21 bit 6.
&S0	DSR will remain ON at all times. (Default.)
&S1	DSR will become active after answer tone has been detected and inactive after the carrier has been 
lost.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

&Tn - Test and Diagnostics
The modem will perform selected test and diagnostic functions according to the parameter supplied. A test can be run only 
when in an asynchronous operation in non-error-correction mode (normal or direct mode). To terminate a test in progress, the 
escape sequence must be entered first, except for parameters 7 and 8 (see Section 3.1.3). If S18 is non-zero, a test will 
terminate automatically after the time specified by S18 and display the OK message.
&T0	Terminates test in progress. Clears S16.
&T1	Initiates local analog loopback, V.54 Loop 3. Sets S16 bit 0. If a connection exists when this 
command is issued, the modem hangs up. The CONNECT XXXX message is displayed upon the 
start of the test.
&T2	Returns ERROR.
&T3	Initiates local digital loopback, V.54 Loop 2. Sets S16 bit 2. If no connection exists, ERROR is 
returned. Sets S16 bit 4 when the test is in progress.
&T4	Enables digital loopback acknowledgment for remote request, i.e., an RDL request from a remote 
modem is allowed. Sets S23 bit 0. (Default.)
&T5	Disables digital loopback acknowledgment for remote request, i.e., an RDL request from a remote 
modem is denied. Clears S23 bit 0.
&T6	Requests a remote digital loopback (RDL), V.54 Loop 2, without self test. If no connection exists, 
ERROR is returned. Sets S16 bit 4 when the test is in progress. The CONNECT XXXX message is 
displayed upon the start of the test.
&T7	Requests a remote digital loopback (RDL),V.54 Loop 2, with self test. (In self test, a test pattern is 
looped back and checked by the modem.) If no connection exists, ERROR is returned. When the 
test is terminated either via expiration of S18, or via the &T0 or H command, the number of detected 
errors is reported to the DTE. Sets S16 bit 5 when the test is in progress.
&T8	Initiates local analog loopback, V.54 Loop 3, with self test. (In self test, a test pattern is looped 
back and checked by the modem.) If a connection exists, the modem hangs up before the test is 
initiated. When the test is terminated either via expiration of S18, or via the &T0 or H command, the 
number of detected errors is reported to the DTE. Sets S16 bit 6 when the test is in progress. 

&V - Display Current Configuration and Stored Profiles
Reports the current (active) configuration, the stored (user) profiles, and the first four stored telephone numbers. The stored 
profiles and telephone numbers are not displayed if the NVRAM is not installed or is not operational as detected by the NVRAM 
test during reset processing. 
Result Code:
OK
Example:
AT&V
ACTIVE PROFILE:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0 &Y0
S00:002 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:030 S08:002 S09:006
S10:014 S11:255 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000 S38:020 S44:020 S46:138 
S48:007 S95:000

STORED PROFILE 0:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0
S00:002 S02:043 S06:002 S07:030 S08:002 S09:006 S10:014 S11:095 S12:050 S18:000
S36:007 S37:000 S40:105 S41:003 S44:020 S46:138 S95:000

STORED PROFILE 1:
B0 E1 L1 M1 N1 QO T V1 W0 X4 Y0 &C0 &D0 &G2 &J0 &K3 &Q5 &R1 &S0 &T4 &X0
S00:002 S02:043 S06:002 S07:030 S08:002 S09:006 S10:014 S11:095 S12:050 S18:000
S36:007 S37:000 S40:105 S41:003 S44:020 S46:138 S95:000

TELEPHONE NUMBERS:
0 = 	1 =
2 = 	3 =

OK

If the NVRAM is not installed or is not operational as detected by the NVRAM test, the following message is displayed:
NVRAM FAILED OR NOT INSTALLED
&Wn - Store Current Configuration
Saves the current (active) configuration (profile), including S-Registers, in one of the two user profiles in NVRAM as denoted 
by the parameter value. This command will yield an ERROR message if the NVRAM is not installed or is not operational as 
detected by the NVRAM test.
The current configuration is comprised of a list of storable parameters illustrated in the &V command. These settings are 
restored to the active configuration upon receiving an Zn command or at power up (see &Yn command).
&W0	Store the current configuration as profile 0.
&W1	Store the current configuration as profile 1.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

&Xn - Select Synchronous Clock Source
Selects the source of the transmit clock for the synchronous mode of operation. The parameter value, if valid, is written to S27 
bits 4 and 5.
In asynchronous mode, the transmit and receive clocks are turned OFF. In synchronous mode, the clocks are turned ON with 
the frequency of 1200 Hz or faster corresponding to the speed that is selected for modem operation.
&X0	Selects internal timing. The modem generates the transmit clock signal and applies it to the TXCLK 
output at the serial interface.
&X1	Selects external timing. The local DTE sources the transmit clock signal on the XTCLK input of the 
serial interface. The modem applies this clock to the TXCLK output at the serial interface.
&X2	Selects slave receive timing. The modem derives the transmit clock signal from the incoming 
carrier and applies it to the TXCLK output at the serial interface.
Result Codes:
OK	n = 0 to 2.
ERROR	Otherwise.
&Yn - Designate a Default Reset Profile
Selects which user profile will be used after a hard reset.
&Y0	The modem will use profile 0.
&Y1	The modem will use profile 1.
Result Codes:
	n = 0 to 1.
ERROR	If n > 1, or if NVRAM  is not installed or is not operational.
&Zn=x - Store Telephone Number
The modem can store up to four telephone numbers and each telephone number dial string can contain up to 35 digits.
&Zn=x	n = 0 to 3 and x = dial string. (Requires 256-byte NVRAM.)
Result Codes:
OK	For n  3 and x  35 digits.
ERROR	If n > 3 or x > 35 digits, or if NVRAM  is not installed or is not operational.
3.2.3.	AT% Commands
%En - Enable/Disable Line Quality Monitor and Auto-Retrain or Fallback/Fall Forward
Controls whether or not the modem will automatically monitor the line quality and request a retrain (%E1) or fall back when line 
quality is insufficient or fall forward when line quality is sufficient (%E2). Applies to dial-up line only. The parameter value, if 
valid, is written to S41 bits 2 and 6.
If enabled, the modem attempts to retrain for a maximum of 30 seconds.
%E0	Disable line quality monitor and auto-retrain. (Default.)
%E1	Enable line quality monitor and auto-retrain.
%E2	Enable line quality monitor and fallback/fall forward.
Result Codes:
OK	n = 0, 1, or 2.
ERROR	Otherwise.

Fallback/Fall Forward. When %E2 is active, the modem monitors the line quality (EQM). When line quality is insufficient, 
the modem will initiate a rate renegotiation to a lower speed within the V.32 bis/V.32 modulation speeds. The modem will keep 
falling back if necessary until the speed reaches 4800 bps. Below this rate, the modem will only do retrains if EQM thresholds 
are exceeded. If the EQM is sufficient for at least one minute, the modem will initiate a rate renegotiation to a higher speed 
within the V.32/V.32bis modulation speeds. The rate renegotiations will be done without a retrain if a V.32bis connection is 
established.
Speeds attempted during fallback/fall forward are those shown to be available in the rate sequences exchanged during the 
initial connection. Fallback/fall forward is available in error correction and normal modes, but not in direct mode or 
synchronous mode with external clocks. 
%L - Line Signal Level
Returns a value which indicates the received signal level. The value returned is a direct indication (DAA dependent) of the 
receive level at the MDP, not at the telephone line connector. For example, 009 = -9 dBm, 043 = -43 dBm, and so on.
Result Codes:
OK
%Q - Line Signal Quality
Reports the line signal quality (DAA dependent). Returns the higher order byte of the EQM value. Based on the EQM value, 
retrain or fallback/fall forward may be initiated if enabled by %E1 or %E2.
Example:
AT%Q

015
Result Codes:
OK	If connected.
ERROR 	If not connected, or connected in 300 bps, V.23, or fax modes.
3.2.4.	AT\ Commands
\Gn - Modem-to-Modem Flow Control (XON/XOFF)
The modem enables or disables the generation or recognition of modem-to-modem XON/XOFF flow control according to the 
parameter supplied. The parameter value, if valid, is written to S41 bit 3.
Due to the buffering system used in the modem, modem-to-modem flow control is normally disabled.
\G0	Disables modem-to-modem XON/XOFF flow control. (Default.)
\G1	Enables modem-to-modem XON/XOFF flow control.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

\Kn - Break Control
Controls the response of the modem to a break received from the DTE or the remote modem according to the parameter 
supplied. The parameter value, if valid, is written to S40 bits 3, 4, and 5.
The response is different in three separate states.
The first state is where the a break is sent to the modem from the DTE when the modem is operating in data transfer mode:
\K0	Enter on-line command mode, no break sent to the remote modem.
\K1	Clear data buffers and send break to remote modem.
\K2	Same as 0.
\K3	Send break to remote modem immediately.
\K4	Same as 0.
\K5	Send break to remote modem in sequence with transmitted data. (Default.)
The second case is where a break is sent to the remote modem when the modem is in the on-line command state (waiting for 
AT commands) during a data connection:
\K0	Clear data buffers and send break to remote modem.
\K1	Clear data buffers and send break to remote modem. (Same as 0.)
\K2	Send break to remote modem immediately.
\K3	Send break to remote modem immediately. (Same as 2.)
\K4	Send break to remote modem in sequence with data.
\K5	Send break to remote modem in sequence with data. (Same as 4.) (Default.)
The third case is where a break is received from a remote modem:
\K0	Clears data buffers and sends break to the DTE.
\K1	Clears data buffers and sends break to the DTE. (Same as 0.)
\K2	Send a break immediately to DTE.
\K3	Send a break immediately to DTE. (Same as 2.)
\K4	Send a break in sequence with received data to DTE.
\K5	Send a break in sequence with received data to DTE. (Same as 4.) (Default.)
Result Codes:
OK	n = 0 to 5.
ERROR	Otherwise.
\Nn - Operating Mode
This command controls the preferred mode to be negotiated in a subsequent data connection. This command is affected by 
the OEM firmware configuration.
\N0	Selects normal speed buffered mode. (Forces &Q6.)
\N1	Serial interface selected - Selects direct mode and is equivalent to &M0, &Q0 mode of operation. 
(Forces &Q0.)
	Parallel interface selected - Same as \N0.
Result Codes:
OK	n = 0 or 1.
ERROR	Otherwise.

3.2.5.	AT+ Commands
+Hn - Enable/Disable RPI and DTE Speed
This command enables or disables Rockwell Protocol Interface (RPI) processing and sets the DTE speed.
+H0	Disable RPI
+H1	Enable RPI and set DTE speed to 19200 bps
+H2	Enable RPI and set DTE speed to 38400 bps
+H3	Enable RPI and set DTE speed to 57600 bps
Result Codes:
OK	n = 0 to 3.
ERROR	Otherwise.

3.3.	AT COMMAND RESULT CODES
The modem responds to commands from the DTE and to activity on the line by signalling to the DTE in the form of result codes. 
The result codes that the modem can send are described below.
Two forms of each result code are available: long-form, an English-like "verbose" response, and short-form, a data-like 
numeric response (included in parentheses following the long-form). The long-form code is preceded and terminated by the 
sequence < CR> < LF>. The short-form is terminated by < CR>, only with no preceding sequence.
If result messages are suppressed, nothing is returned to the DTE. 
00- OK
The OK code is returned by the modem to acknowledge execution of a command line.
01- CONNECT
The modem will send this result code upon connecting when:
1.	The line speed is 300 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or
2.	The DTE speed is 300 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting, or
3.	The range of result code responses is restricted by the X command such that no speed reporting is allowed.
02- RING
The modem sends this result code when incoming ringing is detected on the line. 
03- NO CARRIER
The modem sends this result code when attempting to establish a call if:
1.	Ringback is detected and later ceases but no carrier is detected within the period of time determined by register S7, or
2.	No ringback is detected within the period of time determined by register S7.
This result code is also used when the modem auto-disconnects due to loss of carrier.
Under X0, if busy tone detection is enforced, this result code is used as a response to the detection of busy or circuit busy. 
Under X0, if dial tone detection is enforced or selected, this result code is used to indicate that dial tone has not been 
detected.
04- ERROR
The modem returns this result code if the command line contains a syntax error or it is unable to execute a command 
contained in the command line. It is issued if a command does not exist or if the parameter supplied is outside the permitted 
range.
05- CONNECT 1200
For X1, X2, X3, and X4, the modem sends this result code when:
1.	The line speed is 1200 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or
2.	The DTE speed is 1200 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.
(Also, see the W command.)
06- NO DIALTONE
For X2 and X4, the modem sends this result code if it has been instructed to wait for dial tone during dialing but none is 
received.
07- BUSY
For X3 and X4, if busy tone detection is enforced, the modem sends this result code when attempting to originate a call if the 
busy (engaged) signal is detected on the line.
08- NO ANSWER
The modem sends this result code when attempting to originate a call if a continuous ringback signal is detected on the line 
until the expiration of the timer S7.
09- CONNECT 0600
For X1, X2, X3, and X4, the modem sends this result code when:
1.	The line speed is 600 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or
2.	The DTE speed is 600 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.
10- CONNECT 2400
For X1, X2, X3, and X4, the modem sends this result code when:
1.	The line speed is 2400 bps and the modem has been instructed to report the line speed to the DTE upon connecting, or
2.	The DTE speed is 2400 bps and the modem has been instructed to report the DTE speed to the DTE upon connecting.
11- CONNECT 4800
For X1, X2, X3, and X4, the modem sends this result code when the DTE speed is 4800 bps and the modem has been 
instructed to report the DTE speed upon connecting.
12- CONNECT 9600
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 9600 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
13- CONNECT 7200
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 7200 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
14- CONNECT 12000
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 12000 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
15- CONNECT 14400
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 14400 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
16- CONNECT 19200
For X1, X2, X3, and X4, the modem returns this result code upon connecting when the DTE speed is 19,200 bps and the 
modem has been instructed to report the DTE speed upon connecting.
17- CONNECT 38400
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 38400 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
18- CONNECT 57600
For X1, X2, X3, and X4, the modem sends this result code upon connecting when the DTE speed is 57600 bps and the modem 
has been instructed to report the DTE speed to the DTE upon connecting.
22- CONNECT 75TX/1200RX
For X1, X2, X3, and X4, the modem returns this result code upon establishing a V.23 originate connection when the modem 
has been instructed to report the DCE speed upon connection.
23- CONNECT 1200TX/75RX
For X1, X2, X3, and X4, the modem returns this result code upon establishing a V.23 answer connection when the modem has 
been instructed to report the DCE speed upon connection.
33- FAX
The modem returns this result code when a fax modem connection is established in a facsimile mode.
35- DATA
The modem returns this result code when a data modem connection is established in a facsimile mode.
40- CARRIER 300
The modem returns this result code when either a V.21 or Bell 103 carrier has been detected on the line and carrier reporting 
has been enabled. (See S95 and Xn.)
44- CARRIER 1200/75
The modem sends this result code when the V.23 backward channel carrier has been detected on the line and carrier reporting 
has been enabled. (See S95 and Xn.)
45- CARRIER 75/1200
The modem sends this result code when the V.23 forward channel carrier has been detected on the line and carrier reporting 
has been enabled. (See S95 and Xn.)
46- CARRIER 1200
The modem sends this result code when either the high or low channel carrier in either V.22 or Bell 212 mode has been 
detected on the line and carrier reporting has been enabled. (See S95 and Xn.)
47- CARRIER 2400
The modem sends this result code when either the high or low channel carrier in V.22 bis mode has been detected on the line, 
and carrier reporting has been enabled. (See S95 and Xn.)
48- CARRIER 4800
The modem sends this result code when the 4800 bps data rate in V.32 bis or V.32 mode has been detected on the line, and 
carrier reporting has been enabled. (See S95 and Xn.)
49- CARRIER 7200
The modem sends this result code when the 7200 bps data rate in V.32 bis mode has been detected on the line, and carrier 
reporting has been enabled. (See S95 and Xn.)
50- CARRIER 9600
The modem sends this result code when the 9600 bps data rate in V.32 bis or V.32 mode has been detected on the line, and 
carrier reporting has been enabled. (See S95 and Xn.)
51- CARRIER 12000
The modem sends this result code when the 12000 bps data rate in V.32 bis mode has been detected on the line, and carrier 
reporting has been enabled. (See S95 and Xn.)
52- CARRIER 14400
The modem sends this result code when the 14400 bps data rate in V.32 bis mode has been detected on the line, and carrier 
reporting has been enabled. (See S95 and Xn.)
70- PROTOCOL: NONE
This message is sent to the DTE when the modem has connected without any form of error correction, and the PROTOCOL 
message reporting has been enabled. (See S95 and Xn.)
+F4- +FCERROR
This message is sent to the DTE when high speed fax data (V.27, V.29, V.33, or V.17) is expected and a V.21 signal is 
received.

This page is intentionally blank.

4.	S-REGISTERS
The S-Registers are summarized in Table 4-1 along with their default values. Registers denoted with an '*' in Table 4-1 may be 
stored in one of the two user profiles by entering the &Wn command. One of these profiles may be loaded at any time by using 
the Zn command. Registers or register fields quoted as reserved are reserved for current or future use by the firmware. 
All bit-mapped registers are read-only. The appropriate AT command which controls the relevant bits in the S-Register should 
be used to change the value. 
4.1.	FACTORY DEFAULTS
The factory default values are stored in ROM and are loaded into the active configuration at power up or by the ATZn 
command. In addition, the designated default profile is subsequently loaded, and may change some of the factory default 
values. The designated default profile can be changed by entering the &Yn command where n is one of the two possible user 
profiles.
The defaults shown are those used by Rockwell in factory profiles zero and one. 
The default values shown in Table 4-1 may vary by modem firmware configuration. Consult the MCU firmware release notes for 
exact configuration.
The factory default values may be loaded at any time by entering the &Fn command.

Table 4-1. S-Register Summary
Register	Function	Range	Units	Save	Default
S0	Rings to Auto-Answer	0-255	rings	*	0 
S1	Ring Counter	0-255	rings		0
S2	Escape Character	0-255	ASCII	*	43
S3	Carriage Return Character	0-127	ASCII		13
S4	Line Feed Character	0-127	ASCII		10
S5	Backspace Character	0-255	ASCII		8
S6	Wait Time for Dial Tone	2-255	s	*	2 
S7	Wait Time for Carrier	1-255	s	*	50
S8	Pause Time for Dial Delay Modifier	0-255	s	*	2
S9	Carrier Detect Response Time	1-255	0.1 s	*	6
S10 	Carrier Loss Disconnect Time	1-255	0.1 s 	*	14
S11	DTMF Tone Duration	50-255	0.001 s	*	95
S12	Escape Code Guard Time	0-255	0.02 s 	*	50
S13 	Reserved	-	-		-
S14 	General Bit Mapped Options Status	-	-	*	138 (8Ah)
S15 	Reserved	-	-		-
S16	Test Mode Bit Mapped Options Status
(&T)	-	-		0
S17	Reserved	-	-		-
S18 	Test Timer	0-255	s	*	0
S19-S20	Reserved	-	-		-
S21	V.24/General Bit Mapped Options
Status	-	-	*	4 (04h)
S22 	Speaker/Results Bit Mapped Options
Status	-	-	*	117 (75h)
S23 	General Bit Mapped Options Status		-	*	55 (37h)
S24 	Sleep Inactivity Timer	0-255	s	*	0
S25 	Delay to DTR Off	0-255	s or 0.01 s		5
S26 	RTS-to-CTS Delay	0-255	0.01 s		1
S27 	General Bit Mapped Options Status	-	-	*	73 (49h)
S28 	General Bit-Mapped Options Status	-	-	*	0
S29	Flash Dial Modifier Time	0-255	10 ms		0
S30 	Disconnect Inactivity Timer	0-255	10 s		0
S31 	General Bit-Mapped Options Status	-	-	*	2
S32	XON Character	0-255	ASCII		17 (11h)
S33	XOFF Character	0-255	ASCII		19 (13h)
S34-S36 	Reserved	-	-		-
S37 	Line Connection Speed	-	-	*	0
S38 	Reserved	-	-		-
S39 	Flow Control Bit Mapped Options
Status	-	-	*	3
S40 	General Bit-Mapped Options Status	-	-	*	105 (69h) 
S41	General Bit-Mapped Options Status	-	-	*	3
S42-S45 	Reserved	-	-		-
S91 	PSTN Transmit Attenuation Level	0-15	dBm		10 
S92	Fax Transmit Attenuation Level	0-15	dBm		10
S95 	Result Code Messages Control	-	-	*	0
* Register value may be stored in one of two user profiles with the &W command.									

4.2.	S-REGISTER DEFINITIONS
S0 - Number of Rings to Auto-Answer
Sets the number of the rings required before the modem automatically answers a call. Setting this register to zero disables 
auto-answer mode.
Range:	0-255 rings
Default:	0 
S1 - Ring Counter
S1 is incremented each time the modem detects a ring signal on the telephone line. S1 is cleared if no rings occur over an eight 
second interval.
Range:	0-255 rings
Default:	0
S2 - Escape Character
S2 holds the decimal value of the ASCII character used as the escape character. The default value corresponds to an ASCII 
'+'. A value over 127 disables the escape process, i.e., no escape character will be recognized.
Range:	0-255, ASCII decimal
Default:	43 (+)
S3 - Carriage Return Character
Sets the command line and result code terminator character. Pertains to asynchronous operation only. 
Range:	0-127, ASCII decimal
Default:	13 (Carriage Return)
S4 - Line Feed Character
Sets the character recognized as a line feed. Pertains to asynchronous operation only. The Line Feed control character is 
output after the Carriage Return control character if verbose result codes are used
Range:	0-127, ASCII decimal
Default:	10 (Line Feed)
S5 - Backspace Character
Sets the character recognized as a backspace. Pertains to asynchronous operation only. The modem will not recognize the 
Backspace character if it is set to a value that is greater than 32 ASCII. This character can be used to edit a command line. 
When the echo command is enabled, the modem echoes back to the local DTE the Backspace character, an ASCII space 
character and a second Backspace character; this means a total of three characters are transmitted each time the modem 
processes the Backspace character.
Range:	0-32, ASCII decimal
Default:	8 (Backspace)

S6 - Wait Time for Dial Tone Before Blind Dialing
Sets the length of time, in seconds, that the modem will wait before starting to dial after going off-hook when blind dialing. The 
Wait for Dial Tone call progress feature (W dial modifier in the dial string) will override the value in register S6. 
The modem always pauses for a minimum of 2 seconds, even if the value of S6 is less than 2 seconds. 
Range:	2-255 seconds
Default:	2 
S7 - Wait Time For Dial Tone After W Dial Modifier
Sets the length of time, in seconds, that the modem will wait for dial tone when encountering a W dial modifier before 
continuing with the next dial string parameter.
Range:	1-255 seconds
Default:	50
S8 - Pause Time For Dial Delay
Sets the time, in seconds, that the modem must pause when the , dial modifier is encountered in the dial string.
Range:	0-255 seconds
Default:	2
S9 - Carrier Detect Response Time
Sets the time, in tenths of a second, that the carrier must be present before the modem considers it valid and turns on RLSD. 
As this time is increased, there is less chance to detect a false carrier due to noise from the telephone line.
Range:	1-255 tenths of a second
Default:	6 (0.6 second)
S10 - Lost Carrier To Hang Up Delay
Sets the length of time, in tenths of a second, that the modem waits before hanging up after a loss of 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 register S10 minus the value in register S9. 
Therefore, the S10 value must be greater than the S9 value or else the modem disconnects before it recognizes the carrier.
Range:	1-255 tenths of a second
Default:	14 (1.4 seconds)
S11 - DTMF Tone Duration
Sets the duration of tones in DTMF dialing. This value has no effect on pulse dialing.
Range:	50-255 milliseconds
Default:	95 (95 milliseconds)
S12 - Escape Code Guard Time
Defines the maximum period, in fiftieths of a second, allowed between consecutive asynchronous escape characters (+) for 
the escape sequence to be considered valid.
Range:	0-255 1/50 of a second
Default:	50 (1 second)
S13 - Reserved

S14 - General Bit Mapped Options Status
Indicates the status of command options. 
Default: 138 (8Ah) (10001010b)
Bit 0 	This bit is ignored. 
Bit 1 	Command echo (En)
0 =	Disabled (E0)
1 =	Enabled (E1) (Default.)
Bit 2 	Quiet mode (Qn)
0 =	Send result codes (Q0) (Default.)
1 =	Do not send result codes (Q1)
Bit 3 	Result codes (Vn)
0 =	Numeric (V0) 
1 =	Verbose (V1) (Default.)
Bit 4 	Reserved
Bit 5 	Tone (T)/Pulse (P)
0 =	Tone (T) (Default.)
1 =	Pulse (P)
Bit 6 	Reserved
Bit 7 	Originate/Answer
0 =	Answer
1 =	Originate (Default.)
S15 - Reserved

S16 - General Bit Mapped Test Options Status
Indicates the test in progress status. 
Default:	0
Bit 0 	Local analog loopback
0 =	Disabled (Default.)
1 =	Enabled (&T1)
Bit 1 	Not used
Bit 2 	Local digital loopback
0 =	Disabled (Default.)
1 =	Enabled (&T3)
Bit 3 	Remote digital loopback (RDL) status 
0 =	Modem not in RDL (Default.)
1 =	RDL in progress
Bit 4 	RDL requested (AT&T6)
0 =	RDL not requested (Default.)
1 =	RDL requested (&T6)
Bit 5 	RDL with self test
0 =	Disabled (Default.)
1 =	Enabled (&T7)
Bit 6 	Local analog loopback (LAL) with self test
0 =	Disabled (Default.)
1 =	Enabled (&T8)
Bit 7 	Not used
S17 - Reserved
S18 - Test Timer
Sets the length of time, in seconds, that the modem conducts a test (commanded by &Tn) before returning to the command 
mode. If this register value is zero, the test will not automatically terminate; the test must be terminated from the command 
mode by issuing an &T0 or H command. When S18 is non-zero, the modem returns the OK message upon test termination.
Range:	0-255 seconds
Default:	0
S19-S20 - Reserved

S21 - V.24/General Bit Mapped Options Status
Indicates the status of command options.
Default:	4 (00000100b)
Bit 0 	Set by &Jn command but ignored otherwise.
0 =	&J0 (Default.)
1 =	&J1
Bit 1 	Reserved
Bit 2 	CTS behavior (&Rn)
0 =	CTS tracks RTS (&R0) 
1 =	CTS always on (&R1) (Default.)
Bit 3,4 	DTR behavior (&Dn)
0 =	&D0 selected (Default.)
1 =	&D1 selected
2 =	&D2 selected
3 =	&D3 selected
Bit 5 	RLSD (DCD) behavior (&Cn)
0 =	&C0 selected (Default.)
1 =	&C1 selected
Bit 6 	DSR behavior (&Sn)
0 =	&S0 selected (Default.)
1 =	&S1 selected
Bit 7 	Long space disconnect (Yn)
0 =	Y0 (Default.)
1 =	Y1

S22 - Speaker/Results Bit Mapped Options Status
Indicates the status of command options.
Default:	117 (75h) (01110101b)
Bit 0,1 	Speaker volume (Ln)
0 =	Off (L0)
1 =	Low (L1) (Default.)
2 =	Medium (L2)
3 =	High (L3)
Bit 2,3 	Speaker control (Mn)
0 =	Disabled (M0)
1 =	Off on carrier (M1) (Default.)
2 =	Always on (M2)
3 =	On during handshake (M3)
Bit 4,5,6 	Limit result codes (Xn)
0 =	X0
4 =	X1
5 =	X2
6 =	X3
7 =	X4 (Default.)
Bit 7	Reserved

S23 - General Bit Mapped Options Status
Indicates the status of command options.
Default:	55 (37h) (00110111b)
Bit 0	Grant RDL
0 =	RDL not allowed (&T5)
1 =	RDL allowed (&T4) (Default.)
Bit 1,2,3 	DTE Rate
0 =	0 - 300 bps
1 =	600 bps
2 =	1200 bps
3 =	2400 bps (Default.)
4 =	4800 bps
5 =	9600 bps
6 =	19200 bps
7 =	38400 bps or higher
Bit 4,5 	Assumed DTE parity 
0 =	even
1 =	not used
2 =	odd
3 =	none (Default.)
Bit 6,7 	Guard tone (&Gn)
0 =	None (&G0) (Default.)
1 =	None (&G1)
2 =	1800 Hz (&G2)
S24 - Sleep Inactivity Timer
Sets the length of time, in seconds, that the modem will operate in normal mode with no detected telephone line or DTE line 
activity before entering low-power sleep mode. The timer is reset upon any DTE line or telephone line activity. If the S24 value 
is zero, neither DTE line nor telephone inactivity will cause the modem to enter the sleep mode. 
Range:	0-255 seconds
Default:	0
S25 - Delay To DTR
Sets the length of time that the modem will ignore DTR for taking the action specified by &Dn. Its units are seconds for 
synchronous modes and one hundredths of a second for other modes.
Range:	0-255 (1 second for synchronous modes 1; 0.01 second otherwise )
Default:	5
S26 - RTS to CTS Delay 
Sets the time delay, in hundredths of a second, before the modem turns CTS ON after detecting an OFF-to-ON transition on 
RTS when &R0 is commanded. Pertains to synchronous operation only. 
Range:	0-255 hundredths of a second
Default:	1

S27 - Bit Mapped Options Status
Indicates the status of command options.
Default:	74 (4Ah) (01001010b) (Default.)

Bit 0,1,3 	Synchronous/asynchronous selection (&Mn/&Qn)
3	1	0	
0	0	0	 =	&M0 or &Q0
0	0	1	=	&M1 or &Q1
0	1	0	 =	&M2 or &Q2
0	1	1	 =	&M3 or &Q3
1	0	0	=	Reserved
1	0	1	 =	Reserved
1	1	0	 =	&Q6 (Default.)
Bit 2 	Leased line command (&Ln)
0 =	Dial up line requested (&L0) (Default.)
1 =	Leased line requested (&L1)
Bit 4,5 	Internal clock select (&Xn)
0 =	Internal clock (&X0) (Default.)
1 =	External clock (&X1)
2 =	Slave clock (&X2)
Bit 6 	CCITT/Bell mode select (Bn)
0 =	CCITT mode (B0)
1 =	Bell mode (B1) (Default.)
Bit 7 - Reserved

S28 - Bit Mapped Options Status
Default:	0
Bit 0-1 	Reserved
Bit 2 	Reserved (always 0).
Bit 3,4 	Pulse dialing (&Pn)
0 =	39%-61% make/break ratio at 10 pulses per second (&P0) (Default.)
1 =	33%-67% make/break ratio at 10 pulses per second (&P1)
Bit 5-7 	Reserved
S29 - Flash Dial Modifier Time
Sets the length of time, in units of 10 ms, that the modem will go on-hook when it encounters the flash (!) dial modifier in the dial 
string. 
Range:	0-255 10 ms intervals
Default:	0 (disabled)
S30 - Disconnect Inactivity Timer
Sets the length of time, in tens of seconds, that the modem will stay online before disconnecting when no data is sent or 
received. Any data transmitted will reset the timer. The timer is inoperative in synchronous mode. 
Range:	0-255 tens of seconds (0-2550 seconds)
Default:	0 (disabled)

S31 - Bit Mapped Options Status
Default:	2 (00000010b)
Bit 0 	Reserved
Bit 1 	Automode detection enable/disable (Nn) 
0 =	Disabled (N0)
1 =	Enabled (N1) (Default.)
Bit 2,3 	Connect message control (Wn)
0 =	DTE speed only (W0) (Default.)
1 =	Full reporting (W1)
2 =	DCE speed only (W2)
Bit 3 	Reserved
Bit 4-7 	Reserved
S32 - XON Character
Sets the value of the XON character.
Range:	0-255, ASCII decimal
Default:	17 (11h)
S33 - XOFF Character
Sets the value of the XOFF character.
Range:	0-255, ASCII decimal
Default:	19 (13h)
S34-S36 - Reserved
S37 - Desired Line Connection Speed
Default:	0
Bit 0-3 	Desired line connection speed. This is interlinked with the Fn command. If an invalid number is 
entered, the number is accepted into the register, but S37 will act as if the default value has been 
entered.
0 =	Attempt auto mode connection (F0). (Default)
1-3 =	Attempt to connect at 300 bps (F1).
4 =	Reserved.
5 =	Attempt to connect at V.22 1200 bps (F4).
6 =	Attempt to connect at V.22 bis 2400 bps (F5).
7 =	Attempt to connect at V.23 (F3).
8 =	Attempt to connect at V.32 bis/V.32 4800 bps (F6).
9 =	Attempt to connect at V.32 bis/V.32 9600 bps (F8).
10 =	Attempt to connect at V.32 bis 12000 bps (F9).
11 =	Attempt to connect at V.32 bis 14400 bps (F10).
12 =	Attempt to connect at V.32 bis 7200 bps (F7).
13-15 =	Reserved
Bit 4-7 	Reserved

S38 - Reserved
S39 - Flow Control Bit Mapped Options Status 
Default:	3 (00000011b)
Bits 0-2 	Status of command options
0 =	No flow control 
3 =	RTS/CTS (&K3) (Default.)
4 =	XON/XOFF (&K4)
5 =	Transparent XON (&K5)
6 =	Both methods (&K6)
Bits 3-7 	Reserved
S40 - General Bit Mapped Options Status
Indicates the status of command options.
Default:	105 (69h) (01101001b) 
Bit 0 - 2	Reserved
Bits 3-5 	Break Handling (\Kn)
0 =	\K0
1 =	\K1
2 =	\K2
3 =	\K3
4 =	\K4
5 =	\K5 (Default.)
Bits 6-7 	Reserved
S41 - General Bit Mapped Options Status
Indicates the status of command options.
Default:	131 (10000011b)
Bits 0 -1 	Reserved
Bit 2, 6	Auto retrain and fallback/fall forward (%En)
	Bit 6	Bit 2
	0 	0	=	Retrain and fallback/fall forward disabled (%E0) (Default.)
	0	1	=	Retrain enabled (%E1)
	1	0	=	Fallback/fall forward enabled (%E2)
Bit 3 	Modem-to-modem flow control
0 =	Disabled (\G0) (Default.)
1 =	Enabled (\G1)
Bit 4-5, 7 	Reserved

S91 - PSTN Transmit Attenuation Level
Sets the transmit attenuation level from 0 to 15 dBm for the PSTN mode, resulting in a transmit level from 0 to -15dBm. 
Range:	0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)
Default:	10 (-10 dBm transmit level.)
S92 - Fax Transmit Attenuation Level
Sets the transmit attenuation level from 0 to 15 dBm for the fax mode, resulting in a transmit level from 0 to -15dBm.
Range:	0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)
Default:	10 (-10 dBm transmit level.)
S95 - Extended Result Codes
The bits in this register can be set to override some of the Wn command options. A bit set to a 1 in this register will enable the 
corresponding result code regardless of the Wn setting. Also, refer to Table 3-1. 
Default:	0
Bit 0 =	CONNECT result code indicates DCE speed instead of DTE speed.
Bit 1=	Reserved.
Bit 2 =	Enable CARRIER XXXX result code (XXXX = rate; see Table 3-1).
Bit 3 =	Enable PROTOCOL XXXX result code (XXXX = protocol identifier; see Table 3-1).
Bit 4 -7=	Reserved.


5.	FAX CLASS 1 COMMANDS
5.1.	FAX I/O PROCESSING
The fax I/O interface supports asynchronous serial and parallel interfaces. The interface rate is 19200 bps. The character 
format is 8 bits data, no parity, and 1 stop bit. Start and stop elements are removed from the transmit data and added to the 
receive data. Both transmit and receive data are buffered. Flow control using XON/XOFF (DC1/DC3) or RTS/CTS is provided.
Unique control character strings are identified, filtered, or reinserted into the I/O data stream. These control characters and 
their resultant action are described below.
5.1.1.	DTE-to-Modem Transmit Data Stream
	Characters Detected	Action Taken
	<DLE><data>	Delete <DLE><data> characters.
	<DLE><ETX>	Recognize as a string terminator and take appropriate action.
	<DLE><DLE>	Replace with single <DLE> character.

5.1.2.	Modem-to-DTE Receive Data Stream

	Characters Detected	Action Taken
	<DLE>	Insert extra <DLE> ahead of <DLE>.
The modem also identifies the end of a frame by inserting <DLE><ETX> into the data stream after the FCS bytes. 
5.1.3.	Fax Mode Selection
Fax class 1 commands are identified in Table 5-1. Fax modes and rates are determined by the AT+F commands as described in 
Section 5.2.
Table 5-1.  Fax Class 1 Commands
Command	Function
Service Class ID	
+FCLASS=	Service Class
Fax Class 1 Commands	
+FAE=n	Data/Fax Auto Answer
+FTS=n	Stop Transmission and Wait
+FRS=n	Receive Silence
+FTM=n	Transmit Data
+FRM=n	Receive Data
+FTH=n	Transmit Data with HDLC Framing
+FRH=n	Receive Data with HDLC Framing 

5.1.4.	Fax Origination
Origination of fax calls is made using the ATD command. Upon completion of the dial function, a calling tone at 1100 Hz is 
transmitted, with a cadence of 0.5 seconds on and 3 seconds off. The modem automatically enters mode +FRH=3 and sends 
the CONNECT message to the DTE when FSK flags are detected from the remote.

5.1.5.	Fax Answering
Answering of fax calls is identical to answering of data calls with the exception that the modem enters the fax handshaking 
mode instead of the data handshaking mode after going off-hook. If +FAE=0, the modem, after sending answer tone, 
automatically enters fax mode (+FTH=3), sends the CONNECT message to the DTE, and starts sending FSK flags. If +FAE=1, 
the modem determines whether the caller is a data modem or fax modem and sends the DATA or FAX result code, 
respectively, to the DTE. 
5.1.6.	Fax Control Transmission
Fax control transmission is initiated by the +FTH=n command. After this command is issued, the modem generates the 
CONNECT message and transmits carrier in the modulation scheme specified by the parameter n. The modem then transmits 
HDLC flags for a minimum of 1 second. The modem continues to transmit the HDLC flags until it receives a character from the 
DTE.
When characters are received from the DTE, the modem adds start and end flags, performs zero-bit insertion, generates FCS, 
and deletes <DLE><chr> character pairs before transmitting the characters to the remote fax machine. Each <DLE><DLE> 
sequence is transmitted as a single <DLE>. <DLE><ETX> is considered as the end of frame marker and is not transmitted. All 
data received from the DTE after <DLE><ETX> is ignored by the modem until the modem generates either the CONNECT, OK, 
or ERROR result code.
If no more data is in the transmit buffer and the final bit was a 1 (bit 4 of the second byte received from the DTE), the modem 
generates the OK result code and returns to the command mode. If the final bit was a 0, the modem generates the CONNECT 
message and waits for further data from the DTE while transmitting HDLC flags. If no more data is received before 5 seconds 
elapse, the modem drops carrier, goes on-hook, and generates the ERROR result code.
5.1.7.	Fax Control Reception
Fax control reception is initiated using the AT+FRH=n command. After this command is issued, the modem looks for carrier in 
the modulation scheme specified by the parameter n. If no carrier is detected before the period of time specified by register S7 
expires, the modem generates the NO CARRIER message and returns to command mode. If carrier is detected that is not the 
one specified by the parameter n, the modem generates the +FCERROR message and returns to the command mode. If the 
specified carrier is detected, the modem generates the CONNECT message and enters the HDLC receive mode.
In HDLC receive mode, the modem receives HDLC frames from the remote fax machine, strips the flags, performs zero-bit 
deletion, performs error checking, and handles <DLE><chr> character pairs before passing the data to the DTE. The modem 
prefixes each <DLE> character with another <DLE> character before sending it to the DTE. After the last byte in the frame, the 
modem sends <DLE><ETX> to the DTE marking the end of the frame. The modem then generates either the OK message if no 
errors were detected or the ERROR message if errors were detected (FCS is incorrect), and returns to command mode.
While in command mode, the modem continues to receive data in the selected modulation scheme, and sends the data after 
sending the CONNECT message to the DTE when the DTE reissues the +FRH command with the same parameter. If the DTE 
issues the +FRH command with a different parameter, the modem clears all buffers and proceeds as described previously.
If carrier is lost while in command mode and the DTE reissues the +FRH command with the same parameter, and there is no 
data in the buffer, the modem sends the ERROR result code to the DTE and returns to the command mode. If there is data in 
the buffer, the modem sends the next frame of buffered data to the DTE, followed by <DLE><ETX>, and either the ERROR 
result code if errors were detected or the OK result code if no errors were detected. The modem then returns to command 
mode.
The modem concludes an error is detected if carrier is lost for any period of time during or before the reception of a frame. If 
carrier is lost for a time period longer than the time specified by the register S10, the modem finishes delivering the data in the 
receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the ERROR message, and returns to command mode. All 
subsequent data received from the remote is discarded.
If the modem detects a frame abort sequence (seven consecutive ones with no zero insertion) while it is waiting for a frame 
beginning flag (it was receiving HDLC flags), it will wait for the HDLC flags again until either carrier is lost, or the DTE aborts the 
process by sending an abort character or by dropping DTR with &D2 in effect. If the frame abort sequence is detected while 
the modem is receiving a frame it finishes delivering the data in the receive buffer (if any) to the DTE, sends <DLE><ETX>, 
generates the ERROR message, and returns to command mode. The modem keeps looking for HDLC flags followed by more 
data from the remote, with the selected modulation scheme.
If the modem detects a receive buffer overflow condition, it concludes that there was an FCS error in that frame. The modem 
will receive more frames only if a starting flag is detected and there is room in the receive buffer. If a starting flag is detected 
and there is no room in the buffer, the modem discards all data in that frame.
If the modem receives any character from the DTE after the +FRH command (except flow control characters if software flow 
control is in effect), or if the modem detects a high-to-low transition of the DTR signal while &D1 is in effect, it sends 
<DLE><ETX> to the DTE, generates OK result code, and returns to command mode. The receive buffer is cleared and all data 
received from the remote is discarded. If the modem detects a DTR drop while &D2 is in effect, it goes on-hook, sends 
<DLE><ETX> to the DTE, generates OK result code, and returns to command mode. If the modem detects a DTR drop while 
&D3 is in effect, the modem performs a warm reset.
5.1.8.	Fax Data Transmission
Fax data transmission is initiated by the AT+FTM=n command. After this command is issued, the modem generates the 
CONNECT message and transmits carrier in the modulation scheme specified by the parameter n. The modem then transmits 
constant 1 bits for a minimum of one second and continues to transmit constant 1 bits until it receives a character from the 
DTE.
When data is received from the DTE, the modem deletes start and stop bits and deletes all <DLE><chr> character pairs before 
transmitting the data to the remote. Each <DLE><DLE> sequence is transmitted as a single <DLE>. <DLE><ETX> is 
considered as the end of stream marker, and is not transmitted. All data received from the DTE after the <DLE><ETX> is 
ignored by the modem until the modem generates either the CONNECT, OK, or ERROR result code.
If no more data is in the transmit buffer, and the last transmitted character was not an ASCII NULL, the modem generates the 
OK result code and returns to the command mode. If the last character transmitted was an ASCII NULL, the modem generates 
the CONNECT message to the DTE and waits for further data from the DTE while transmitting NULLs to the remote. If more 
data is received before five seconds elapse, the modem continues to transmit the data as described in the previous 
paragraph. If five seconds elapse and no data is received from the DTE, the modem drops carrier, goes on-hook, and 
generates the ERROR result code.
5.1.9.	Fax Data Reception
Fax data reception is initiated using the AT+FRM=n command. After this command is issued, the modem looks for carrier in the 
modulation scheme specified by the parameter n. If no carrier is detected before the period of time specified by register S7 
expires, the modem generates the NO CARRIER message and returns to command mode. If a V.21 carrier is detected when a 
high speed carrier is expected, the modem generates the +FCERROR message and returns to the command mode. If the 
specified carrier is detected, the modem generates the CONNECT message and enters the data receive mode.
While in data receive mode, the modem receives data from the remote, adds start and stop bits, and handles <DLE><chr> 
character pairs before passing the data to the DTE. The modem prefixes each <DLE> character with another <DLE> character 
before sending it to the DTE.
If carrier is lost for a time period longer than the time specified by the register S10, the modem finishes delivering the data in 
the receive buffer (if any) to the DTE, sends <DLE><ETX>, generates the NO CARRIER result code, and returns to the 
command mode. All subsequent data received from the remote is discarded.
If the modem detects a receive buffer overflow condition, it stops receiving from the remote until there is room in the receive 
buffer. The modem informs the DTE of the buffer overflow after it sends to the DTE the last character that was stored in the 
buffer before the overflow occurred.
If the modem receives any character from the DTE after the +FRM command (except flow control characters if software flow 
control is in effect), or if the modem detects a high-to-low transition of the DTR signal while &D1 is in effect, it sends 
<DLE><ETX> to the DTE, generates the OK result code, and returns to command mode. The receive buffer is cleared and all 
data received from the remote is discarded. If loss of DTR is detected while &D2 is in effect, the modem goes on-hook, sends 
<DLE><ETX> followed by OK result code to the DTE, and returns to command mode. If the modem detects a DTR drop while 
&D3 is in effect, the modem performs a warm reset.

5.2.	COMMANDS
+FCLASS=n - Select Service Class
+FCLASS=n command sets the active service class.
Parameters: 0-1 
Command options:
+FCLASS=0	Select Data Mode (Default.)
+FCLASS=1	Select Facsimile Class 1
+F<command>? - Report Active Configuration
+F<command>? interrogates the modem to determine the active configuration.
Typical responses are:
+FAE?	0 if auto answer is disabled; 1 if auto answer is enabled
+FCLASS?	0 if in data mode; 1 if in fax class 1;
+F<command>=? - Report Operating Capabilities
+F<command>=? can be used to determine the operating capabilities of the modem.
Typical responses are:
+FAE=?	0 or 1
+FCLASS=?	0, or 1
+FTM=?	24, 48, 72, 96 (9600 bps version)
+FRM=?	24, 48, 72, 96 (9600 bps version)
+FTM=?	24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146 (14400 bps version)
+FRM=?	24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146 (14400 bps version)
+FAE=n - Data/Fax Auto Answer
+FAE=n 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. 
Parameters: n = 0 or 1
Command options:
n = 0	Disable data/fax auto answer mode. The modem answers as a fax modem only. (Default).
n = 1	Enable data/fax auto answer mode. The modem answers as a fax or data modem.
After a data (not fax) connection is acheived (indicated by the DATA result code), the DTE must issue an ATO command to 
cause the modem to go on-line.
+FTS=n - Stop Transmission and Wait
+FTS=n causes the modem to terminate a transmission and wait for n 10-ms intervals before responding with the OK result 
code. An ERROR response code results if this command is issued while the modem is on-hook.
+FRS=n - Receive Silence
+FRS=n causes the modem to report back to the DTE with an OK result code after n 10 ms-intervals of silence have been 
detected on the line. This command is aborted if any character is received from the DTE. The modem discards the aborting 
character and issues an OK result code. An ERROR response code results if this command is issued while the modem is on-
hook.

+FTM=n - Transmit Data
+FTM=n causes the modem to transmit data using the modulation defined below. An ERROR response code results if this 
command is issued while the modem is on-hook.
Parameters: See Command options
Command options:
	+FTM=24	V.27 ter 2400 bps
	+FTM=48	V.27 ter 4800 bps
	+FTM=72	V.29 7200 bps
	+FTM=73	V.17 7200 bps long
	+FTM=74	V.17 7200 bps short 
	+FTM=96	V.29 9600 bps
	+FTM=97	V.17 9600 bps long
	+FTM=98	V.17 9600 bps short
	+FTM=121	V.17 12000 bps long
	+FTM=122	V.17 12000 bps short
	+FTM=145	V.17 14400 bps long
	+FTM=146	V.17 14400 bps short
+FRM=n - Receive Data
+FRM=n causes the modem to enter the receiver mode using the modulation defined below. An ERROR response code results 
if this command is issued while the modem is on-hook.
Parameters: See Command options
Command options:
	+FRM=24	V.27 ter 2400 bps
	+FRM=48	V.27 ter 4800 bps
	+FRM=72	V.29 7200 bps 
	+FRM=73	V.17 7200 bps long 
	+FRM=74	V.17 7200 bps short 
	+FRM=96	V.29 9600 bps 
	+FRM=97	V.17 9600 bps long
	+FRM=98	V.17 9600 bps short
	+FRM=121	V.17 12000 bps long
	+FRM=122	V.17 12000 bps short
	+FRM=145	V.17 14400 bps long
	+FRM=146	V.17 14400 bps short

+FTH=n - Transmit Data with HDLC Framing
+FTH=n causes the modem to transmit data using HDLC protocol and the modulation defined below. An ERROR response code 
results if this command is issued while the modem is on-hook.
Parameters: See Command options.
Command options:
	+FTH=3	V.21 channel 2 300 bps
	+FTH=24	V.27 ter 2400 bps
	+FTH=48	V.27 ter 4800 bps
	+FTH=72	V.29 7200 bps
	+FTH=73	V.17 7200 bps long 
	+FTH=74	V.17 7200 bps short 
	+FTH=96	V.29 9600 bps
	+FTH=97	V.17 9600 bps long
	+FTH=98	V.17 9600 bps short
	+FTH=121	V.17 12000 bps long
	+FTH=122	V.17 12000 bps short
	+FTH=145	V.17 14400 bps long
	+FTH=146	V.17 14400 bps short
+FRH=n - Receive Data with HDLC Framing
+FRH=n causes the modem to receive frames using HDLC protocol and the modulation defined below. An ERROR response 
code results if this command is issued while the modem is on-hook.
Parameters: See Command options.
Command options:
	+FTH=3	V.21 channel 2 300 bps
	+FRH=24	V.27 ter 2400 bps
	+FRH=48	V.27 ter 4800 bps
	+FRH=72	V.29 7200 bps
	+FRH=73	V.17 7200 bps long 
	+FRH=74	V.17 7200 bps short 
	+FRH=96	V.29 9600 bps
	+FRH=97	V.17 9600 bps long
	+FRH=98	V.17 9600 bps short
	+FRH=121	V.17 12000 bps long
	+FRH=122	V.17 12000 bps short
	+FRH=145	V.17 14400 bps long
	+FRH=146	V.17 14400 bps short
5.3.	EXAMPLES
Examples of calling (transmitting) and answering (receiving) one page using fax class 1 commands are shown in Tables 5-2 
and 5-3, respectively. 


Table 5-2. Fax Class 1 Calling Sequence (One Page)
	DTE Commands	DCE Responses	
	(Host)	(Modem)	Remote Fax	Notes
	(1)	AT+FCLASS=1	(2)	OK			Set to Class 1
	PHASE A
	(3)	ATDT6163	(4)	Dials	(5)	Answers	+FRH=3 implied by Dialing
			(6)	CONNECT	(7)	Send HDLC flags
	PHASE B
						(8)	Send NSF frame
			(9)	<NSF>,OK
	(10)	AT+FRH=3	(11)	CONNECT
					(12)	Send CSI frame
			(13)	<CSI>,OK
	(14)	AT+FRH=3	(15)	CONNECT
					(16)	Send DIS frame	Last frame bit = 1
			(17)	<DIS>,OK	(18)	Drop carrier
	(19)	AT+FTH=3	(20)	Send HDLC flags	(21)	Receive flags
			(21)	CONNECT
	(22)	<TSI>	(23)	Send TSI frame	(24)	Receive TSI	Last frame bit = 0
			(25)	CONNECT
	(26)	<DCS>	(27)	Send DCS frame	(28)	Receive DCS	Last frame bit = 1
			(29)	Detect last frame bit
			(39)	OK, drop carrier
	(31)	AT+FTS=8	(32)	OK, wait 80 ms
	(33)	AT+FTM=96	(34)	Send V.29
			(35)	CONNECT
	(36)	<TCF>	(37)	Send TCF data	(38)	Receive & check
			(39)	OK
	(40)	AT+FRH=3	(41)	CONNECT
			(42)	Send CFR frame		Last frame bit = 1
	(43)	<CFR>,OK	(44)	Drop carrier
			(45)	OK
	PHASE C
	(46)	AT+FTM=96	(47)	Send V.29
			(48)	CONNECT
	(49)	age data	(50)	Send page data	(51)	Receive data
			(52)	OK
	(53)	AT+FTH=3	(54)	Send HDLC flags	(55)	Receive flags
			(56)	CONNECT
	PHASE D
	(57)	<EOP>	(58)	Send EOP frame	(59)	Receive EOP	Last frame bit = 1
			(60)	OK, drop carrier
	(61)	AT+FRH=3	(62)	CONNECT
					(63)	Send MCF frame	Last frame bit = 1
			(64)	<MCF>, OK
	(65)	AT+FTH=3	(66)	Send HDLC flags	(67)	Receive flags
			(68)	CONNECT
	(69)	<DCN>	(70)	Send DCN frame	(71)	Receive DCN	Last frame bit = 1
			(72)	OK, drop carrier
	PHASE E
	(73)	ATH0	(74)	OK, hang up	(75)	Hang up

Table 5-3. Fax Class 1 Answering Sequence (One Page)
	DTE Commands	DCE Responses		
	(Host)	(Modem)	Remote Fax	Notes
	(1)	AT+FCLASS=1	(2)	OK			Set to Class 1
	PHASE A
					(3)	FAX machine dials
			(4)	RING
	(5)	ATA	(6)	Modem answers
			(7)	Send HDLC flags	(8)	Receive flags	+FTH=3 implied by
							answering
			(9)	CONNECT
	PHASE B
	(10)	<NSF>	(11)	Send NSF frame	(12)	Receive NSF	Last frame bit = 0
			(13)	CONNECT
	(14)	<CSI>	(15)	Send CSI frame	(16)	Receive CSI	Last frame bit = 0
			(17)	CONNECT
	(18)	<DIS>	(19)	Send DIS frame 	(20)	Receive DIS	Last frame bit = 1
			(21)	OK, drop carrier
	(22)	AT+FRH=3	(23)	CONNECT
					(24)	Send TSI frame	Last frame bit = 0
			(25)	<TSI>, OK
	(26)	AT+FRH=3	(27)	CONNECT
					(28)	Send DCS frame	Last frame bit = 1
			(29)	<DCS>, OK	(30)	Drop Carrier
	(31)	AT+FRM=96
					(32)	Send V.29
			(33)	CONNECT	(34)	Send TCF frame
			(35)	<TCF>	(36)	Drop carrier
			(37)	NO CARRIER
	(38)	AT+FTH=3	(39)	CONNECT
	(40)	<CFR>	(41)	Send CFR frame	(42)	Receive CFR	Last frame bit = 1
			(43)	OK, drop carrier
	PHASE C
	(44)	AT+FRM=96
					(45)	Send page data
			(46)	<page data>	(47)	Drop carrier
			(48)	NO CARRIER
	PHASE D
	(49)	AT+FRH=3	(50)	CONNECT
					(51)	Send EOP frame	Last frame bit = 1
			(52)	<EOP>, OK
	(53)	AT+FTH=3	(54)	CONNECT
	(55)	<MCF>	(56)	Send MCF frame	(57)	Receive MCF	Last frame bit = 1
			(58)	OK, drop carrier
	(59)	AT+FRH=3	(60)	CONNECT
					(61)	Send DCN frame 	Last frame bit = 1
			(62)	<DCN>, OK
	PHASE E
	(73)	ATH0	(74)	OK, hang up	(75)	Hang up	


A.	AT COMMAND SET SUMMARY
A.1.	BASIC AT COMMANDS

	Command	Function
A/	Re-execute command.
A	Go off-hook and attempt to answer a call.
B0	Select V.22 connection at 1200 bps.
B1	Select Bell 212A connection at 1200 bps.
C1	Return OK message.
Dn	Dial modifier.
E0	Turn off command echo.
E1	Turn on command echo.
F0	Select auto-detect mode (equivalent to N1).
F1	Select V.21 or Bell 103.
F2	Reserved.
F3	Select V.23 line modulation.
F4	Select V.22 or Bell 212A 1200 bps line speed.
F5	Select V.22 bis line modulation.
F6	Select V.32 bis or V.32 4800 line modulation.
F7	Select V.32 bis 7200 line modulation.
F8	Select V.32 bis or V.32 9600 line modulation.
F9	Select V.32 bis 12000 line modulation.
F10	Select V.32 bis 14400 line modulation.
H0	Initiate a hang-up sequence.
H1	If on-hook, go off-hook and enter command mode.
I0	Report product code.
I1	Report pre-computed checksum.
I3	Report firmware revision, model, and interface type.
I4	Report response programmed by an OEM.
I5	Report the country code parameter.
I6	Report modem data pump model.
L0	Set low speaker volume.
L1	Set low speaker volume.
L2	Set medium speaker volume.
L3	Set high speaker volume.
M0	Turn speaker off.
M1	Turn speaker on during handshaking and turn speaker off while receiving carrier.
M2	Turn speaker on during handshaking and while receiving carrier.
M3	Turn speaker off during dialing and receiving carrier and turn speaker on during answering.
N0	Turn off Automode detection.
N1	Turn on Automode detection.
O0	Go on-line.
O1	Go on-line and initiate a retrain sequence.
P	Force pulse dialing.
Q0	Allow result codes to DTE.
Q1	Inhibit result codes to DTE.
Sn	Select S-Register as default.
Sn?	Return the value of S-Register n.
=v	Set default S-Register to value v.
?	Return the value of default S-Register.
T	Force DTMF dialing.
V0	Report short form (terse) result codes.
V1	Report long form (verbose) result codes.
W0	Report DTE speed.
W1	Report line speed, PROTOCOL NONE, and DTE speed.
W2	Report DCE speed.
X0	Report basic call progress result codes, i.e., OK, CONNECT, RING, NO CARRIER (also, for busy, if 
enabled, and dial tone not detected), NO ANSWER and ERROR.
X1	Report basic call progress result codes and connections speeds (OK, CONNECT, RING, NO 
CARRIER (also, for busy, if enabled, and dial tone not detected), NO ANSWER, CONNECT XXXX, 
and ERROR.
X2	Report basic call progress result codes and connections speeds, i.e., OK, CONNECT, RING, NO 
CARRIER (also, for busy, if enabled, and dial tone not detected), NO ANSWER, CONNECT XXXX, 
and ERROR.
X3	Report basic call progress result codes and connection rate, i.e., OK, CONNECT, RING, NO 
CARRIER, NO ANSWER, CONNECT XXXX, BUSY, and ERROR.
X4	Report all call progress result codes and connection rate, i.e., OK, CONNECT, RING, NO 
CARRIER, NO ANSWER, CONNECT XXXX, BUSY, NO DIAL TONE and ERROR.
Y0	Disable long space disconnect before on-hook.
Y1	Enable long space disconnect before on-hook.
Z0	Restore stored profile 0 after warm reset.
Z1	Restore stored profile 1 after warm reset.
&C0	Force RLSD active regardless of the carrier state.
&C1	Allow RLSD to follow the carrier state.
&D0	Interpret DTR ON-to-OFF transition per &Qn.
&D1	Interpret DTR ON-to-OFF transition per &Qn.
&D2 	Interpret DTR ON-to-OFF transition per &Qn.
&D3	Interpret DTR ON-to-OFF transition per &Qn.
&F0	Restore factory configuration 0.
&F1	Restore factory configuration1.
&G0	Disable guard tone.
&G1	Disable guard tone.
&G2	Enable 1800 Hz guard tone.
&J0	Set S-Register response only for compatibility.
&J1	Set S-Register response only for compatibility.
&K0	Disable DTE/DCE flow control.
&K3	Enable RTS/CTS DTE/DCE flow control.
&K4	Enable XON/XOFF DTE/DCE flow control.
&K5 	Enables transparent XON/XOFF flow control.
&K6 	Enables both RTS/CTS and XON/XOFF flow control. 
&M0	Select direct asynchronous mode.
&M1	Select sync connect with async off-line command mode.*
&M2	Select sync connect with async off-line command mode and enable DTR dialing of directory zero.*
&M3	Select sync connect with async off-line command mode and enable DTR to act as Talk/Data 
switch.*
&P0	Set 10 pps pulse dial with 39%/61% make/break.
&P1	Set 10 pps pulse dial with 33%/67% make/break.
&Q0	Select direct asynchronous mode.
&Q1	Select sync connect with async off-line command mode.*
&Q2	Select sync connect with async off-line command mode and enable DTR dialing of directory zero.*
&Q3	Select sync connect with async off-line command mode and enable DTR to act as Talk/Data 
switch.*
&Q6	Select asynchronous operation in normal mode.
&R0	CTS tracks RTS (async).
&R1	CTS is always active.
&S0	DSR is always active.
&S1	DSR acts per V.25.
&T0	Terminate any test in progress.
&T1	Initiate local analog loopback.
&T2	Returns ERROR result code.
&T3	Initiate local digital loopback.
&T4	Allow remote digital loopback.
&T5	Disallow remote digital loopback request.
&T6	Request an RDL without self-test.
&T7	Request an RDL with self-test.
&T8	Initiate local analog loop with self-test.
&V	Display current configurations.
&W0	Store the active profile in NVRAM profile 0.
&W1	Store the active profile in NVRAM profile 1.
&X0	Select internal timing for the transmit clock.
&X1	Select external timing for the transmit clock.
&X2	Select slave receive timing for the transmit clock.
&Y0	Recall stored profile 0 upon power up.
&Y1	Recall stored profile 1 upon power up.
&Zn=x	Store dial string x (to 45) to location n (0 to 3).
%E0	Disable line quality monitor and auto retrain.
%E1	Enable line quality monitor and auto retrain.
%E2	Enable line quality monitor and fallback/fall forward.
%L	Return received line signal level.
%Q	Report the line signal quality.
\G0	Disable modem to modem flow control.
\G1	Enable modem to modem flow control.
\Kn	Controls break handling during three states.
\N0	Select normal speed buffered mode.
A.2.	FAX CLASS 1
+FCLASS=n	Service class.
+FAE=n	Data/fax auto answer
+FRH=n	Receive data with HDLC framing.
+FRM=n	Receive data.
+FRS=n	Receive silence.
+FTH=n	Transmit data with HDLC framing.
+FTM=n	Transmit data.
+FTS=n	Stop transmission and wait.


* Serial interface operation only.

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DIGITAL COMMUNICATIONS DIVISION
REGIONAL SALES OFFICES

Headquarters
Digital Communications Division
Rockwell International
4311 Jamboree Road
Newport Beach, CA 92660-3095
(Mailing Address)
P.O. Box C
Newport Beach, CA 92658-8902
Tel: (714) 833-4600
Fax: (714) 833-4078
Fax: (714) 833-4391


USA - Southwest
Digital Communications Division
Rockwell International
5000 Birch Street
Suite 400
Newport Beach, CA 92660-3095
Tel: (714) 833-4655
Fax: (714) 833-6898

USA - Southeast
Digital Communications Division
Rockwell International
One Copley Parkway
Suite 210
Morrisville, NC 27560
Tel: (919) 467-7703
Fax: (919) 467-6096

USA - North Central
Digital Communications Division
Rockwell International
3158 South River Road
Suite 204
Des Plaines, IL 60018
Tel: (708) 297-8875
Fax: (708) 297-3230

USA - South Central
Digital Communications Division
Rockwell International
2001 N. Collins Blvd.
Suite 103
Richardson, TX 75080
Tel: (214) 994-4020
Fax: (214) 994-4028

USA - Mid Atlantic
Digital Communications Division
Rockwell International
5001-B Greentree
Executive Campus
Route 73
Marlton, NJ 08053
Tel: (609) 596-0090
Fax: (609) 596-5681



USA - Northeast and 
Canada East
Digital Communications Division
Rockwell International
239 Littleton Road
Suite 1B
Westford, MA 01886
Tel: (508) 692-7660
Fax: (508) 692-8185
TLX (MCI) 6502512464



USA - Northwest and 
Canada West
Digital Communications Division
Rockwell International
3600 Pruneridge Avenue
Suite 100
Santa Clara, CA 95051
Tel: (408) 249-9696
Fax: (408) 249-6518



Japan
Digital Communications Division
Rockwell International Japan Co., Ltd.
Sogo Hanzomon Bldg., 8F 
7, Kojimachi 1-chome, Chiyoda-ku
Tokyo
Japan 102
Tel: (81-3) 3-265-8808
Fax: (81-3) 3-263-0639
TLX: J22198

Australia
Digital Communications Division
Rockwell International
3 Thomas Holt Drive
P.O. Box 165
North Ryde, NSW 2113
Australia
Tel: (61-2) 805-5555
Fax: (61-2) 805-5599
TLX: AA30450

Hong Kong
Digital Communications Division
Rockwell International
13th Floor, Suites 6dex 13
92082 Paris La Defense 2
0
Harbour Centre
25 Harbour Road
Wanchai
Hong Kong 
Tel: (852) 827-0181
Fax: (852) 827-6488

Korea
Digital Communications Division
Rockwell International
Rm. 608 Leema Bldg.
146-1 Soosong-Dong
Chongro-Ku
K.P.O. Box 527
Seoul
Korea
(Dept. 553)
Tel: (82-2) 736-9121
Fax: (82-2) 736-9124

Taiwan
Digital Communications Division
Rockwell International
Room 2808
International Trade Building
333 Keelung Road, Section 1
Taipei
Taiwan 10548, R.O.C.
Tel: (886-2) 720-0282
Fax: (886-2) 757-6760
TLX: 26049 ENTTPE

Germany
Digital Communications Division
Rockwell International GmbH
Paul-Gerhardt-Allee 50 a
8000 Mnchen 60
West Germany
Tel: (49-89) 829-1320
Fax: (49-89) 834-2734
TLX: 521-2650 rimd d





United Kingdom
Digital Communications Division
Rockwell International Ltd.
Central House
3, Lampton Road
Hounslow, Middlesex TW3 1HY
England
Tel: (44-81) 577-2800
Fax: (44-81) 570-0758




France
Digital Communications Division
Rockwell International
Tour GAN, 16 Place de I'Iris
Cedex 13
92082 Paris La Defense 2
France
Tel: (33-1) 49-06-39-80
Fax: (33-1) 49-06-39-90




Italy
Digital Communications Division
Rockwell International Corporation
Via Tortona, 33
20144 Milano
Italy
Tel: (39-2) 47790-226
Fax: (39-2) 4120-642










