基于sip协议的VoIP、视频会议源码，对防火墙穿透协议支持较好，跨平台，支持Linux/Unix,Wingdows,CE,Symbian等,Sip agreement based on VoIP, video conferencing source of support to better penetrate the firewall, cross-platform support for Linux/Unix, Wingdows, CE, Symbian, etc.

The windowed sinc filter uses the inverse fourier transform of ideal low - pass filter frequency response. The Inverse transform of the ideal low - pass response is the sinc function (sinx/x). The inverse fourier transform of the required frequency r

google到了windows上面的sip server 2008 + x-lite的挺简单的（带图文教程），所以照着做了一下，也可以连上自己的服务器。(Google came to windows SIP Server 2008 + X-Lite's simple (with graphics and tutorials), so do it, or connect to your server.)