Squibcakes,

Sounds like Bell 202 to me. Mark = 1200hz, Space = 2200hz Baud = 1200. Used to be common in radio modems.

If you can handle non PBP code then:
The "Rat_Ring" http://groups.yahoo.com/group/rat_ring/ has a software version for the 16F84A/16F628 or 16F877/18F452. It includes Bell202, V23 and caller ID reception.

Or, for existing hardware solutions try a Google search for "bell 202 radio modem" (no quotes) for a long list of possibilities.
<hr>Now, back to the original question.

The problem with standard PWM is that it's a square wave. You would then need a hardware filter etc. to convert it to a sine wave that would be required to send over the radio. You could easily generate the tones at the proper rates, but shapping the wave form is going to be costly.

You're correct, the minimum Freqout duration is 1ms.
If you're using a PIC on the opposite end to receive the signal, could you just settle for 1000 baud instead of 1200? 1/1000 = 1ms. or is it being received by some existing hardware that can't be changed?

Best regards,
&nbsp;&nbsp;Darrel Taylor