Originally Posted by balwinder124

i want to interface a dtmf decoder with 8051 for controlling two stepper motors from a mobile. plese send me the circuit diagram as soon as possible. my email id is

balwinder124@gmail.com

I have done this project before 2 years.
It is very simple.
But sorry to say, I don't have circuit diagram of this.

But its very simple, 4 pins of DTMF decoder goes to microcontroller.
Thats all.


you can go through datasheet of DTMF decoder for rest connection

Let me know if you need any more help.

Originally Posted by john.l

can you please tell me the name of dtmf decoder??

DTMF Decoder - MT8870
DTMF Encoder - UM91215B

Originally Posted by john.l

thanks for the information,
do i need to use both ?
I mean encoder and decoder ?

that purely depends on your application
encoder is exactly reverse to decoder
which means it takes BCD as an input and generate DTMF tone at its output..

Originally Posted by balwinder124

i want to interface a dtmf decoder with 8051 for controlling two stepper motors from a mobile. plese send me the circuit diagram as soon as possible. my email id is

balwinder124@gmail.com

Your mail id is unnecessary in a forum post.
How do you like to encode before you decode it. Is it from an encoder or mobile itself?

balwinder124 is silent for a long time, probably he has found the solution, so he is busy on doing it