“The advantages of using the Internet for voice communications
are instantly recognized by most people: Low or no cost
long-distance telephone calls and the added flexibility
Internet-based applications give over the technological dinosaur,
the telephone. In addition, both conference calls and video
conferencing are possible with suitable compression technology and
adequate bandwidth. It is even estimated that by 2002, 15% of all
voice traffic around the world will be carried by IP networks.”
“There are even Internet-to-phone programs available such as
dial-pad. Most commercial solutions for voiceover IP, however, are
limited to Windows and Macs. There are, however, free and open
source projects available for Linux.”
“The first voice-over-IP program I looked at was Speak Freely,
developed by John Walker and Brian C. Wiles. Speak Freely is a
complete Internet telephone solution featuring conferencing, an
answering machine and encryption. There are both Unix and Windows
clients. Interestingly, Speak Freely offers many compression
protocols including GSM, ADPCM, LPC and LPC-10.”