>As part of a PIC project (naturally), I need to find a transmitter /
>reciever that will allow me to send a simple DTMF tone up to 1/4 mile.
>I've found a number of RF data links, but I really don't need anything
>that complicated.  Needs to be crystal controlled.


I didn't think about it when I sent you the link, but are you making the
DTMF,
or does the transmitter have to do that as well?

The one I sent you is an rs-232 programmable synthesized transmitter in the
US ham 2meter band (144-148 Mhz)  There will be versions for 440 and 902-928
also, but they are not ready yet.

If you're making the DTMF, then you're all set. There's an audio input, as
well as
the mic input, and you can easily set it to transmit when the TTL input is
active,
although it was designed to run autonomously.