The Design And Implementation Of Real-time Fax In VoIP Gateway

With the rapid development of optical communication and digital transmission technology, various IP technology oriented applications are widely in use. As a typical IP application, VoIP gains much attention and development with the trend of broadband and real-time application.By taking advantages of Internet coverage and low-cost, Facsimile over IP (FoIP) do not only realize the traditional fax functions but also facilitate the development of new functions. So has its unique advantages compared with traditional fax. As a critical part of the FoIP system, FoIP gateway needs use a simple, practical agreement on the establishment of the network call. The modularization and the seamless conversion between protocols will be meaningful in practice usage. But the interactions between these protocols are not completely standardized. So the realization of real-time FoIP in VoIP gateway, and the interconnection between different protocols are of critical practical significance.According to the issue of task, this thesis analyzes the procedure of traditional fax communication. The current situation of realized technology and related agreements in FoIP are discussed in depth. With the expatiation and comparison of different signal protocols, a generic implement of FoIP scheme in SIP based gateway is proposed. So the major concept and the design ideas of this scheme are described detailedly in this thesis. This FoIP scheme has been adopted in residential gateway and video conference system project already. The result and practice has proved that it is a portable and applicable solution in various situations.