Research And Implementation Of IP Phone Terminal Based On SIP Protocol

NGN (Next Generation Network) is an important milestone of the telecommunication history. By optimizing network structure, the NGN brings us the fusion of network and business. VoIP (Voice over Internet Protocol) has showed a broad application prospect in this background as a new network service.There are two major signaling protocols in VoIP field, ITU-T recommends H.323 and IETF (Internet Engineering Task Force) delivers SIP (Session Initiation Protocol). Although there are a little hard terminals which are all based on H.323 with complex functions and high development costs, common IP Phones are mainly soft terminals presently. Audio processing chip CM109 which is a USB audio controller specifically for VoIP applications is adopted in this thesis. Call function is integrated on PC, the IP Phone terminal is seen as a PC device through USB interface, and SIP call is realized by open-source protocol stack, oSIP/eXoSIP, and two related protocol, SDP, RTP/RTCP.Overall, the design tasks are made up of hardware design and software design.The hardware section includes audio processing chip (CM109) peripheral circuits, flash controller (UT169) circuit, USB interface circuit, keyboard scanning circuit, EEPROM (93C46) circuit, microphone circuit, buzzer circuit, power circuit and the other I/O interface circuits, etc.The software section realizes construction and analysis of SIP message, sends and receives RTP / RTCP data in Windows platform and VC++6.0 compiler environment. Meanwhile, the final SIP session is actualized based on ANSI C, open-source protocol stacks, oSIP/ eXoSIP and oRTP.In addition, a USB-ROM with FLASH memory is produced for convenience. The session program is solidified into FLASH and configured as AUTORUN mode. The whole system design is completed by this step in the thesis.Finally, a specific experimental environment is constructed to validate the signaling protocols and terminal functions. At the same time, the SIP Phone terminal testing results are showed in this thesis. Design defects and improved ideas in the future are analysised.