Design And Implementation Of VoIP Gateway

Internet has been unprecedented progress and widely applied in recent years.But the status of IP protocol system as a core technology has got the extensive approbation in the data network. At the same time, along with every technology being put forward, particularly VoIP, it makes data network correspondence melt into the traditional voice business gradually. VoIP is an advance method that makes use of the IP network to realize voice correspondence. Its purpose is to transmit tranditional analog voice signal via current IP-centric networks, because of the convenience and economy of networks. It is a kind of network deliverring technique completely based on IP. It converters analog voice to digital sign throngh using voice gateway, soft switch and so on. Then the data can be packed and transmitted through IP network. The purpose address can identify the data, uncomprese and revert voice signal. Because the VoIP technique continuously mature, it is possible to replaces the traditional telephone network with the Internet.VoIP network is composed of IP phone Gateway, Gatekeeper, supporting system, telephone network and IP network. The telephone network can be interoperated with IP network by the Gateway. Gateway is an important equipment of Terminal. There are two main technologic implements of VoIP terminal: based on PC and based on hardware Phone. And the most are based on PC in the market. The purpose of the paper is to design a VoIP terminal based on H.323. It is an embedded system based on hardware Phone and can make a timely voice communication between POTS. Among the majority of their implementation, the voice Gateway plays a very important role. It transforms the PSTN data frame format into IP packet format, and it also translates the switch signaling and protocols between PSTN and IP.In present dissertation, the design and implementation of the VoIP Gatway are discussed. In the first of the dissertation, the technology of VoIP is summed up. Firstly, aim and meaning of VoIP are introduced and the functions that VoIP should have and the standards that VoIP should stand by are expatiated. According to these the paper is provided, the principle and key technology of VoIP are introduced. In the followingpart, as is compared, we can adopt a design method based on ASIC. Furtherly, it makes a description of hardware circuit design in detail and the designing of a voice Gateway software driver is presented based on VxWorks. At last, system test program and result is given.