My original plan was to let the transmitter PTT control the Micor encoder board as usual, but supply a "valid user signal present" logic input to abruptly stop the tone when there is no user signal present... thus allowing the controller to keep the transmitter keyed for IDs without PL tone. This would also kill the reverse burst capability.
But wait! (this is a little complicated to explain) What if I divorced J401-2 from keyed filtered A+ on the exciter and instead used my "valid user signal present" logic to supply keyed filtered A+ to that pin? The controller PTT would control transmitter PTT as normal. "Valid user signal" logic would control the tone encoder. Suppose I then put a diode between the collector of Q707 and J401-4 (delayed keyed filtered A+) and used logic from the collector of Q707 (inverted) to pull Pin 701 low when Q707 shuts off. I think this would: 1) allow the controller to keep the transmitter keyed for *both* valid user signals and IDs by way of normal transmitter PTT 2) allow valid user signal logic to control the tone encoder in such a way that there would be no tone output unless there was a valid user signal... and allow the decoder to do reverse burst after loss of valid user signal, then abruptly kill the tone instead of reverting to "normal" tone. If anyone followed my poor description... are there flaws in my thinking? Perhaps I am over-engineering here? Paul
