The Research And Implementation Of IP Telephony Based On H.323

Since 1990s, the rapid development of Internet has greatly influenced the telecommunication field. The research of multi-media correspondence system on exchanging network is gradually becoming the research focus of people. The technical maturity of audio and video compression, real-time data transfer and network makes it possible to realize the multi-media correspondence on the IP network.This paper begins with the history and status quo of voice correspondence, and then concludes that voice packed is the inevitable direction of the development of voice correspondence. After that it discusses several kinds of realizing methods of voice packed, and points that IP telephony has the greatest developing advantage. Which is the main work of this paper. In chapter 2 we first study several kinds of international standards for IP telephony and mainly study IP telephony based on H.323 standards that has been our country standards for IP telephony field. The key technique of IP telephony is studied too. The long-termed and near-period project of the IP network telephone system on H.323 standards was designed in Chapter 3, considering the developing hotspot of IP telephony. Long-term p roject i s a c omplete s olution, but the period of i ts d evelopment i s 1 onger. However near-period project is suitable for us to develop at present. Whole system of near-period project includes Gatekeeper, autoanswer machine server, one to four port IP network telephone HUB, IP network telephone, USB interface terminal of an DP telephone, standard H.323 terminals etc. Whole system constitute an IP PBX system, which not only has the basic function of an IP network telephone, but also has part of the ability of supplementary service, such as call transfer, and have part of the ability of UMS. These all have the most advanced ideas. Gatekeeper that not only c ompletes the basicfunction but also realizes call transfer function is designed and implemented particularly in chapter 4 according to the project of near-period in chapter 3. In chapter 5, autoanswer machine and other equipments in our system were designed and implemented. In this chapter our whole system is tested and acquired a well test result.