文档介绍：摘 要
当蔻,蕤着全球蛙弱隶场开敖茅彝竞争懿嚣蓝激烈,电信遮营业玉嚣蝮饕歪大的变革,传统的电信网技术正在发生蓿深刻的变革,通信市场的竞争也愈演愈烈。语囊网上基予愿电鼹交换数监务将逐灏转移囊以分缀交换秘数据遴售燕基戳懿结构上,丽在这种赫础结构上,IP将占主要地位。VOIP技术成为通信行业最火热豹焦点之一,很多运营巅酆相继攘出了VOIP业务。VOIP技术发其业务的迅速发展,对传统的电话业务特别是阑际、国内长途电话业务构成了洹大的冲击, 其题大的潜在需求吸弓l了越来越多的运营齑和设备提供商加入这一领域。
本文褪出了基于VO/P原理的通信系统的方案设计和实现,以天津教育科研 IP电话系统为项目勰景。该系统采用USB总线实现主机与用户电话的连接,改变了以往PC视端耳机和麦克风模式的语音通话,方便了用户的使用。自行设计的电话实现了USB通信,它采用Cygnal51单片机和目前比较先进的AMBE算法,与传统构PCM压缩算法毙,极大地掇商了语街压缩比侈1j,同时减少了PC 机对终端的数据采集频率,为PC机节省了大部分的资源。PC机端软件只霈在看台运行,,其中RTP和RTCP协议的使用大大提高了通话时的语音质量,减少了抖动和时延,使整个系统的稳定性得到了大大豹提菇张改善。服务器端网守静设计增强了系统酌安全往,数攒库管理系统为高级用户提供了话务管理的功能。
本系统涎需镶莰宅话线路帮麴遴毫话邋藩礴络设备,节错了建设奄话潮络静设备费、线路费和工程费,可以取得很好的经济效益。而且,基于本系统的设计特点,可敬方便戆溪秀羹宅话麓户,扩大电{丢豹普及蔫蘑。该系统在教育系统、辩技系统、电业系统、银行系统和公安系统等行业的电话通信上有着广泛的推广及应鼹藤景。
关键词:VOIP;;网守;网关
Abstract
Nowadays,with the opening of the global market and the ever—petition,munications industry is about to witness great changes: challenges for the traditional works technology and petition in the .work based on circuit switching will gradually give way to a work based on packet switching and munication in
which IP will take the :VoIP technology has e one of the many concentrations and many manufacturers are launching VOIP service one after anothef. The growth of VOIP technology and its service has brought great impact on the
traditional telephone service especially on inland and intemational long distance call service,and attracted a growing number of manufacturers and device providers to be part of the VOIP field due to its enormous potentials.
communication system based on system is based on the project of IP telephone system of Tian Jin this is conveniently used to connect PC and user telephone rather than earphone and
self-designed user terminal guarantees the USB—munication
by having a Cygnal 5l MCU and AMBE algorithm used on the terminal circuit board. The client software on the PC runs with background mode which transmits data
work wi