As part of my undergraduate requirment at Worcester Polytechnic Institute, I developed a software which allows real time point-to-point voice communications over the Internet. This software which we called it Ethernet Phone, runs under the Linux OS. Ethernet Phone was also developed by a fellow student under MS Windows 3.1 however the source for the MS Windows version is not released on the public domain. Below are features of the E-Phone for Linux.

Ethernet Phone provides real time voice communication over the Internet. This software was tested on two machines that were placed side by side. The time difference between the moment the user on machine A started talking and the moment the user on machine B heard the user on machine A, was less than 100 msec.

Ethernet Phone provides a point-to-point voice communication over the Internet.

Ethernet Phone includes a daemon which notifies the user when a client someone@somewhere.net is trying to contact the user via E-Phone.

An easy to use graphical user interface developed under X Windows. Take a look at the documentation to view snap shots of the UI.

Ethernet Phone provides a "virtual" duplex voice communication with a half duplex sound card. The software will automatically open a channel for either recording or playback by detecting whether the user is in listening mode or in talking mode.

Ethernet Phone includes an "in house" silense supression or Voice Activation Detector (VAD) to conserve bandwidth and avoid transmission of "background noise".

Both the source code and binaries are available for FREE.

And much more ...

A combined technical report on Ethernet Phone for both the Linux and MS Windows OS.

README file describing the installation requirments.

Click here to download the Ethernet Phone 1.01 source code

The Road Ahead

• A complete rewrite to include a better Voice Activation Detector, a better voice codec with high compression ratio, a multi-threaded application in which recording, playback, and network transmission is done on seperate threads.
• Support for H.323. This will allow E-Phone to talk to Windows based voice applications which support H.323 such as NetMeeting and Internet Phone.
• Use of H.323 based codec's such as G711, G723, and/or G729a, etc. Using these vocoders will ensure interoperatibility with H.323 compliant software and also provide us with better voice compression than what can be achieved with the IMA ADPCM codec.
• Better intuitive graphical interface using either Java, GTK, QT, or anything else.
• And anything else you guys can think off ...

Sound/Audio resources on the web

Other Internet Voice/Video Related Applications and reviews

The Unix Sound System(USS Lite) Page maintained by Hannu Savolainen

The Linux SOUND HOWTO by Jeff Tranter

Speech Compression Sites

The GSM Site at the Technical University of Berlin

Sun Microsystems, Inc. released a CCITT based adpcm encoder & decoder capable of 3, 4 and 5-bit coding. Refer to the README file for more information on the code. Download the source code here.

Check out this site for various speech compression/coding softwares