The Study And Realization Of Core Technology Of The LAN Network Telephone Systems

Presently, the development and application of the modern information technology gets abroad. The network voice communication technology applied in the field of modern science and technology gets deepening and for its need of high quality sound communication technology, so that it comes to the combination of excellent audio coding technology and highly efficiency network transmission. Based on this background that is the search and design of network audio communication software concerning the server has become a hot topic during the development of the network., the paper researches and designs a software platform for transmitting audio information via the network..Firstly, the article outlines the development of the computer network, then introduces the basic theory of voice signal, the standards of audio data compression-MPEG-4 CELP. Briefly, intros the developing direction and characteristics. In this foundation, stress and analyze the arithmetic and principle of MPEG-4 CELP, at the same time, achieve the scheme and flow chart and implementation of the function of coding/decoding modules. The communication function based on (C/S) network mode is realized using the technology of Socket net programming. Then, the UDP net protocol is written and the data gram is transmitted in the module of the net transmission. The overall frame module of the whole system is fixed according to the design request and communication function. The interfaces of coding and net transmission modules are putted apart and the function of IP phone system is implemented.With systematically researching the overall flow to design the system for the network voice communication and deepens the understanding for communication software design. Via testing the software of network phone system on the platform of VC++, realizes the function of audio communication in LAN.