How to control Modem by TAPI and how to realize asynchronous input and output of by Win32 communication API are introduced. And the protocol of series port communication is founded to realize file transmission.

• 介绍了如何通过Microsoft的电话应用编程接口(TAPI)控制Modem和通过Win32通信API函数实现串口的异步I/O,建立了串口通信的相应协议,以实现文件传输。