基于开源的PHPSIP类进行扩充改写，实现了php的SIP 客户端的基础功能，重点是扩展支持DTMF，同时支持SIPINFO模式和rfc2833协议；说起来，这个功能并不复杂，但基于对协议的理解（网上相关资料不完整），确实化了我很多时间！因为PHPSIP本身是开源的，所以我还是把自己的代码开源出来！(Extended rewriting of PHPSIP class based on open source implements the basic functions of SIP client of php. The emphasis is on expanding support for DTMF while supporting SIPINFO mode and rfc2833 protocol. This function is not complicated, but based on the understanding of the protocol (incomplete information on the Internet), it really took me a lot of time! Because PHPSIP itself is open source, I still open my own code.)