DTMF编码/解码器DTMF(Dual Tone Multi-Frequency)就是通常在电话机上使用的双音频信号。早期的电话拨号使用的都是脉冲电话系统,与机械式电话相兼容,其中0~9是通过向电话交换机发送脉冲的数量来识别的。这种方式连接速度慢、功能少、设备庞大、寿命短,逐步被先进的程控电话所 DTMF Coder / Decoder DTMF (Dual Tone Multi-Frequency) is the dual audio signal commonly used on telephones. Earlier telephone dialing uses pulse telephone systems that are compatible with mechanical telephones, of which 0 to 9 are identified by the number of pulses sent to the telephone exchange. This method of slow connection, less functionality, large equipment, short life expectancy, and gradually being advanced program-controlled telephone