Functional Architectural Design for Internet Telephony Gateway

The Internet’s phenomenal growth, worldwide coverage and increasing data delivery capabilities have made possible its use as an alternative communications medium for real-time voice messages. In addition, using the Internet medium for voice communication circumvents the high costs of long-distance phone rates. This paper discusses the functional architectural design of an Internet Telephony Gateway (ITG) to support real-time Internet voice communication using conventional telephone system (PSTN). The design uses voice modem and sound card to provide the basic interface with the PSTN. This interface is complemented with software functions that control the modem’s operations. In addition, the ITG handles voice communication over the Internet according to an internationally recognised standard, ITU H.323 Recommendation.