当今数字手机一般都设有双音多频DTMF(Dual Tone Multi Freguency)功能,是手机普遍采用的拨号方式。手机用音频组合信号与交换机或相应终端设备联络,每个组合信号用两个音频频率,故称为双音(DT);不同的信号用不同的频率组合,因此称为多频(MF),总称便是双音多频(DTMF)。手机采用了国际电报电话咨询委员会(CCITT)推荐的8个不同的双音频电话机组合频率,1000Hz以 Today’s digital handsets are generally equipped with dual tone multi-frequency DTMF (Dual Tone Multi Freguency) function, is commonly used dial-up method of mobile phones. The handset uses an audio combination signal to communicate with the exchange or the corresponding terminal equipment. Each combination signal uses two audio frequencies and is therefore referred to as two-tone (DT). Different signals are combined with different frequencies and hence are called multi-frequency (MF) The general term is dual tone multi-frequency (DTMF). The phone incorporates eight different dual-tone phone combinations recommended by the International Telegraph and Telephone Consultative Committee (CCITT) at 1000Hz