著名的SIP协议栈，为GNU开源项目。通过其提供的API接口，可以轻易开发出基于SIP协议栈的VOIP应用程序。-famous SIP protocol stack for the GNU open source projects. Through its interface with the API, can easily develop SIP-based VoIP protocol stack applications.

IAX client库, 一个VOIP的库. 支持H.323和SIP, PBX就是采用的它-the IAX client, a VoIP libraries. Support H.323 and SIP, PBX it is the

YakaPhone, 著名的VOIP客户端, 需要使用iax库和QT库.界面很漂亮-YakaPhone, the famous VoIP client. iax need to use the library and the QT. Interface is very beautiful