Marty,
Sorry, I misunderstood your question because the answer seems so simple.
One possible solution is that you can put a mating connector for the end of
the existing cable that presently connects to your 920 on some little box
available at Radio Shack. Once you have done this you will have two pigtails
exiting the box. On pigtail will contain mostly straight through wiring and
will have a connector on it to connect to your rig as did the original cable.
The second pigtail will be a two wire cable that will connect to one of the
920 accessory connectors and will provide PTT and GND from a optocoupler you
placed on a little circuit board in the box.
Your biggest problem will be to ensure that your rig control is not using both
the DTR or RTS that you intend on using for PTT control. You need to research
and try to find out this information. If necessary, you can may a short 9
wire patch cable to place between your existing serial cable end and the 920.
The idea here is that you can disconnect DTR and RTS one at a time then run
your rig control and ensure that there is no adverse effects. The DTR or RTS
line that is not being used is the one you will use for the adapter described
in the paragraph above.
Come on out to Tom's tonight and we can discuss it further.
Best Regards,
Dave KG0US
Marty Tippin wrote:
> Anyone know of a good way to split out the DTR (or RTS) signals on the rig
> control serial port? My FT-920 doesn't support PTT on the rig port, but if
> I could get to DTR or RTS on that same serial cable, I could route those
> through an optoisolator to drive the external PTT on the rig. I suppose
> there must be some sort of "breakout box" you can put in line with the
> cable but not sure what it is or who carries it.
>
> Any ideas short of building my own custom cable?
>
> -Marty NW0L
> martyt@pobox.com
>
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