在电话拨号时 ，每个按键都使用双频信号进行区分的，本MATLAB程序就是用来模拟发送号码的发送和接受过程，并发出按键音。-In a telephone dial-up, each button using the dual-band signal distinction, the MATLAB program is used to simulate the sending number to send and accept the process and issue the key tone.