Yes, I have used DTMF on other projects, but I had to keep costs REAL low,
on this one; hence the option for single tones, generated by the processor
itself. I know there is some code around here to generate DTMF, but they are
quite bulky and I also needed the memory space.

Anyway, the hardware is done now. And it really works fine when you see the
resulting signal on a scope. That's why I am so puzzled with this strange
behavior...

Thanks for your help !






At 17:00 08/01/98 +1300, you wrote:
>Yes, you should transmit a continuous signal. At the receiving end you
>will need an amplifier with AGC and a limiter in order to recover
>jitter-free signals. The continuous signal gives the AGC something to
>work on. But you should consider a DTMF tone decoder chip, and
>transmitting sine waves with DTMF, I would think.