                       Information for Internet CALL

This page is originated from http://dsp.ee.cuhk.edu.hk/proj/icallinf.html.
You can find the most updated one there.

System Requirement of Internet CALL PC Version

* 486DX2-66 CPU

* 8MB DRAM

* Microsoft Windows 95 or Microsoft Windows NT

* 9.6kbps modem under SLIP/CSLIP/PPP or fixed Internet connection using
32-bit Winsock library

* Windows compatible full-duplex sound board or two half-duplex sound
boards for full duplex or one half-duplex sound board for half-duplex

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System Requirement of Internet CALL SUN Version

* SUN SPARCStation series workstation (I've tested 4, 5, 10, 20 and Ultra
1)

* Audio hardware support

* Solaris 2.3, 2.4 or 2.5

* Motif 1.2 run-time library

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Tips for Internet CALL

How to uncompress

* For PC version, type "pkunzip chatxxxx.zip"

* For SUN version, type "gzip -d < chatxxxx.tar.gz | tar xvf -"

How to run

* For PC version, type "chat" at DOS prompt to run.

* For SUN version, type "./chat" at Xterm to run.

How to use Internet CALL

* New Connect - Start to call remote side. The hostname field is Internet
hostname or the IP address of the remote side. The port number is the
binded port number of remote daemon. You may also use the "Locate" function
to search the one you call to.

   * Domain Specific Locator (DSL) - A function that is used to find the
     remote receiver who has a dynamic IP address. The hostname field is
     any hostname within the domain of your receiver. The user name field
     is the alias of your receiver. The timeout field is the number of
     seconds to wait for the response.

* Preferences

   * Silence threshold (default 500) - the threshold value to be regard the
     audio signal as noise or voice. The larger the value, the more is the
     resistance to background noise.

   * Play delay - the number of frames to be collected before putting them
     to the sound card. More overhead time is needed for smaller delay but
     you will gain in the response time. This parameter can be optimized in
     calibration on Win32 version.

   * Record delay - the number of frames will be bufferred by the sound
     card at one time. Lower delay can decrease the response time but
     increases the overhead time which causes lower speech quality. This
     parameter can be optimized in calibration on Win32 version.

   * Internet connection speed (PC Win32 version only) - the speed of your
     internet conection. This parameter determines the amount of headers to
     be inserted to the voice data to comply with the data rate.

   * User name - the alias that others can find you using the Domain
     Specific Locator.

   * Daemon port (default 6170) - the TCP port binded for waiting for
     connections. You can change it to other unused ports if the default
     one is in use and the Domain Specific Locator can still find you.

   * Half-duplex mode only - it indicates both local and remote the type of
     connection to be made. If you are having a full-duplex sound card, you
     can clear this check box. This parameter can be optimized in
     calibration on Win32 version.

   * Coder - (PC Win32 version only) there are two coders at this time for
     selection: One needs less computation but have lower voice quality.
     One needs more computation to produce better quality. Pentium 90 or
     faster users are recomended to use the later one. This parameter can
     be optimized in calibration on Win32 version.

   * Intial quality - the initial value to be set for defining the
     computation complexity when a call is started. This parameter can be
     optimized in calibration on Win32 version.

* Calibration (PC Win32 version only) - An automatic calibration function
to test and optimize the system parameters.

* The Phone Button - a one-click button for making connections, answering
calls, toggling in half-duplex mode and hanging up. The responses are shown
below.

   * Hangup ->clicked-> New Connect
   * Ringing ->clicked-> Chat or Send
   * Chat ->clicked-> Hangup
   * Send ->LEFT clicked-> Receive
   * Send ->RIGHT clicked-> Hangup
   * Receive ->RIGHT clicked-> Hangup

Miscellaneous

* To adjust the playing and recording volume, for PC, you can use the
"Volume Control" program in Windows, and for SUN, you can use the
"audiocontrol" command.

* The Domain Specific Locator is now binding a UDP port at 6171. If your
computer cannot bind this port or this port is used already. Please report
to me.

Troubleshooting

* When I started Internet CALL, it shows me a lot of error messages,
"Unable to create socket", "Unable to bind port", "Unable to listen to
port", ...
Ans:It is due to the WSOCK32.DLL is not activated. Internet CALL for Win95
requires 32-bit Winsock library with connected in SLIP/PPP or fixed
Internet network connection.

* I have entered the hostname of remote in the "Connect" dialog but it
displays "Unable to resolve hostname".
Ans: Please ensure you have typed the hostname correctly. If the same error
message is appeared again, your DNS may not have the hostname you typed in
its database. You can ask your remote to give you the IP address instead.
Internet CALL supports IP address field also.

* I used the domain specific locator to find my friend in a domain, but it
always replies "Unable to find user in the domain specified".
Ans: If you are using Icall version 0.4b4 or ealier, please download the
version 0.4b5 or later since version 0.4b4 used a methodology that is not
working on all domains. Some domains may refuse requests. If you are using
version 0.4b5 or later, please ensure the hostname you entered is really on
the domain of your caller. You can confirm it by asking the remote whether
the hostname you typed has the network address its domain, i.e. the first 3
numbers in the IP address "abc.def.ghi.xxx" are the same. Also, please
confirm the user name typed is the name that your caller has set in the
"Preferences" setting. If it is still not working, please contact me.

* I have connected with a friend but I cannot hear anything.
Ans: Please ensure the cables of your audio system is plugged properly and
the volume setting is not too low. If it still does not work, please see in
the status bar the third column if you can see the number is accumulating.
If the number is freezed, your remote may not be talking or its data are
all lost in an unstable transmission pathway.

* I cannot record anything or when I start talking, the indicators do not
display what they should be.
Ans: Hang up the call and try to increase your record delay to reduce the
overhead time and then connect again. If it is still not working, please
contact me.

* The troubleshooting section is not completed yet. If you have any problem
that is not listed, please feel free to send emails to
cmwu@cixt.cuhk.edu.hk. Your kindly response will surely enhance our
product.

Frequently Asked Questions (FAQ)

* What is Internet CALL?
Internet CALL is a software providing point-to-point real-time voice
communciations over Internet. It can be operating in half duplex or full
duplex mode. Internet CALL is a free product developed by Department of
Eletronic Engineering, the Chinese University of Hong Kong, under the
project "Interactive Voice Communications systems". Free downloads can be
obtained from http://dsp.ee.cuhk.edu.hk/proj/icalldl.html.

* How Internet CALL makes a connection?
Icall is aiming at providing private coversations over two points. It does
not plugged into any IRC or Web servers for registration. i.e. You would
not be called by anyone that you do not know since they cannot find you.
However, for the people you want to receive their calls, you have to tell
them the hostname you are using. When they call you, they just need to
input the hostname you told to them and Icall will connect them with you
directly.

* What is domain-specific locator (DSL) and how it works?
Domain-Specific Locator (DSL) is a tool for solving the dynamic IP
allocation problem. It can be used to find a remote user at a specific
domain but may have different IP addresses. DSL asks you to fill in one of
the hostnames in the particular domain as well as the name of user you want
to find. DSL will try to contact with all hosts that has the same netmask
"255.255.255.0" of the IP address of the hostname you typed. i.e. the 254
hosts of IP addresses abc.def.ghi.xxx will be searched. If Internet CALL is
activated, DSL will check if the name you typed matches the one in the
"Preferences" setting. of the remote side If they are matched, DSL will
tell you it has found the user you want.

* What does the daemon port means?
The daemon port is a number that the Icall daemon binds. It should be 6170
by default but it fails to bind at this port, you can change to another
one. However, you have to tell your friends for your particular daemon port
number, or DSL can it out for them.

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Last modified August 12, 1996.
Copyright  1996 EE CUHK. All rights reserved.
