A TELEPHONE ADAPTER FOR INTERNET TELEPHONY SYSTEMS

In order to make the Internet telephony system a step closer to being a viable replacement of the conventional telephony system, an Internet telephone adapter (ITA) is proposed to interface a conventional telep hone to the host computer. With the ITA, there is no longer the need f or the current practice of using the host computer's microphone as the audio input and the internal or external speaker as the audio output to carry out a conversation. Users are able to dial an Internet teleph one number to make a connection, be notified of an incoming Internet c all through ringing of the telephone set, and carry out a conversation using the conventional telephone handset. This paper describes the de sign and development of an ITA which is connected to the parallel port of the host computer and optionally, to an existing sound card in the host computer. This will allow the ITA to be used as a stand-alone de vice or in conjunction with a sound card to support full-duplex real-t ime voice communication across the Internet. (C) 1997 Elsevier Science B.V.