说明：  osip，exosip，ortp...是在网络电话中使用非常广泛的几个开源库。这里是在VC7环境下已经编译好的lib文件和dll文件，在windows环境下可以直接使用，省却了重新编译的烦恼。
(osip, exosip, ortp ... is the phone in the network is widely used in several open source libraries. Here is the VC7 environment has been compiled lib files and dll files in the windows environment, can be used directly without the need to re-compile troubles.)