Dtmf

hi,

we are doing a DTMF project based on CM 8870 DTMF receiver. it is not working . could you help us.

thanks
lijo

hi khin,
Please post your full circuit diagram and explain what sort of problems you are having, its impossible to make a guess, based on the information you have posted.

Regards

We have problem with the DTMF receiver section . We have to get Binary o/p (at pin 11,12,13,14) corresponding to the DTMF signal given to the capacitor which is connected to pin 2 and 3 through 100k resistance. We are using DTMF tranmitter UM 91214B IC . The o/p of transmitter is verified on CRO,its working .
Our problem is that when we give the DTMF signal to the input f the DTMF receiver IC , we are getting nothing at the o/p pins. what we expect is

0 0 0 1 for key 1
0 0 1 0 for key 2
0 0 1 1 for key 3 etc..

hi khin,
Is this the circuit you are using for the transmitter?