Based On The Sip Voip Application System Design

VoIP is a voice telephony based on Internet Protocol. It is the essential capacity of triple play products, so it’s one of the main capabilities of optical access terminal products.The hardware of VoIP system mainly includes CPU, DSP and SLIC. The cooperation of them is the key technology. At software level,the VoIP system is divided into Signaling Protocol Stack, Audio Processing, Media Transfer, VoIP Management, and Master Controller modules. SIP is chosen in signaling level and RTP is used in media transport.The operating system of the design is embedded Linux.This paper presents a set of APIs including most functionalities of the two-chip DSP and SLIC of VoIP service.I hope the industry could pay attention to the APIs research. DSP and SLIC interfaces include two categories of configuration and event report. The DSP configuration functions include voice codec, echo canceller, comfort noise generation and so on.Event report includes various tones such as DTMF. SLIC configuration includes line feeding, ring and other functions.The voice service is the center of the application, including basic call,3way conference and fax. At the software level, the flow of the service process is refined from module level to code level. The main method of feature test is packet capture of SIP and RTP, and all services pass the test.