非常实用的SIP软电话API，可以直接在vs2008下编译，简单调用api的接口，就可以实现软电话的所有功能，作者使用开源的exosip、ortp、mediastream等接口，进行封装，用户也可以以这个为基础，做出自己想要的软电话接口，改API目前支持多种语音编码，在易用性，稳定性上超过著名的linphone，作者对linphone也比较了解，在开发前全面分析了解linphone的代码。(A very practical SIP soft phone API can be compiled directly under VS2008 and all functions of the soft phone can be realized by simply calling the interface of the api. The author uses open source interfaces such as exosip, ortp and mediastream to encapsulate it. Users can also use this as the basis to make the soft phone interface they want. The API can support a variety of voice coding at present. It is easy to use and stable. More than the well-known linphone, the author also has a better understanding of the linphone, before the development of a comprehensive analysis of the linphone code.)