Dtmf Decoder

Some articles on dtmf decoder, dtmf:

Internet Radio Linking Project - Requirements - IRLP Hardware
... The most difficult part being the DTMF decoder which consists of a MT8870 (or similar) DTMF decoder IC and HCF4081 (or similar) and-gate IC ... pins 10,12,13,15 in order to acknowledge a DTMF digit ... MT8870 pin 15 provides a pulse when any valid DTMF digit is decoded, so this signal is used on one input of each gate on the HCF4081 ...