Introduction - If you have any usage issues, please Google them yourself
DTMF (Dual Tone Multi Frequency) signal tone phone dialing signal. Developed by AT & T Bell Laboratories, dual-tone multi-frequency signal coding techniques are easy to identify, anti-interference ability and the number issued faster, more economical and practical than the modem for remote transmission, this dialing method to replace the traditional pulse dialing. Telephone dual tone multi-frequency signal has two purposes: one for dual tone multi-frequency signal a dial to control the switch is turned on the called subscriber telephone second is the use of dual tone multi-frequency signal remote telephone various action, such as playing a message, voice mail. These are inseparable from the generation of DTMF signals. Detailed needs analysis of flow chart and code.