Introduction - If you have any usage issues, please Google them yourself
Two-way DTMF collection/fat MT8880 IC specifically for the dual audio signals received, the design, it could have sent dual audio signal, while the dual audio signal decoding receiver, but also to judge the sound signal (dial tone , ring back tone, busy tone). Above is its application circuit and procedures
Packet : 9927439mt8880code.rar filelist
MT8880应用程序.doc