Hi all,

(Yes I have searched the subject here, and my own almost un_answered words came back to me :( )

I am still stuck up with MT8880.

It is transmitting and doing call progress OK but the problem is that it is not at decoding the received DTMF data.

Although the interrupt at IRQ pin 12 IC is occurring that this pin on any DTMF tone received goes low.

Mind you the IC is in only in DTMF mode in which it is supposed to decode the received DTMF data.

I am using it with 89c2051.

Kindly give me the step by step algorithm to decode the data.


I am shouting for help, its desperate now.

Thank you

Simon