用于测试pjsip的几个简单功能，实现了打电话、自动接电话，发送MESSAGE,INFO等几个功能。-A few simple test pjsip function to achieve the call, automatically answer the phone, send the MESSAGE, INFO, and several other functions.

基于sip协议，用asterisk作为服务器，实现voip软电话功能，实现了接听，呼叫，挂机，呼叫转移，以及通信录等功能。-Based on sip protocol, with the asterisk as a server, voip soft phone capabilities to achieve and realize the answer, call, hang up, call forwarding, and address book functions.