DTMF tone generator using microcontroller

双音多频（DTMF）信号发生器的使用源程序，vc 编写，与《双音多频（DTMF）接收器的使用源程序》联合用-Dual-Tone Multi-Frequency (DTMF) signals using the generator source, vc preparation, and "Dual-Tone Multi-Frequency (DTMF) receiver to the source using" joint use