Mark K Sullivan wrote:
> Before you go to all of this trouble, are you sure an A/D is cheaper than a
> dedicated DTMF decoder?  I have used the Mitel/Teltone 8870 successfully in
 the
> past.  It takes a color burst crystal which can also be the PIC clock and only
 a
> pair of resistors.
>
> - Mark Sullivan -

Thank you for your ideas Mark, but I don't want to use a dedicated IC, I just
 know that this can be done with
the 16C61 and I want to know how.

Octavio