DTMF Decoder using MT 8870

Thread Starter


Joined Mar 12, 2013
Dear all,
I'm working on a circuit to control the water pump based on DTMF code and cellphone.
But the DTMF section is not working properly.
While sending the DTMF code, pin # 11 to 14 is on high and no change in state and pin # 16 is at low state.
This is the case for all DTMF codes which we are sending.
Kindly see the circuit and somebody please help me. :(