The TRS Data jack (vs the DIN one) combines the PTT and audio in
(for transmitting) on the Tip of that TRS plug.? You need a 2k-ish
resistor between the tip and the PTT line, and a DC blocking
capacitor (a couple of uf) between the tip and your audio source.?
The PTT signal can come from a variety of places.? Assuming you are
using a sound card TNC (Direwolf, AGWPE, UZ7HO, et al), most use the
serial port "modem lines" (DTR, RTS), with an appropriate buffer
circuit.? That can be as simple as a transistor and resistor in an
"open collector" circuit configuration.? The PTT is an active-low,
so driving the transistor on with the modem line going high will do
it, but be sure that the software configuration uses the modem lines
in the right manner.? Some are active the wrong way, which kind of
makes a mess of things.
Actually I should back up and first ask what you are using for the
TNC, and what sort of interface you are using between it and the
rig.? Is it just a custom cable between the computer and radio, or
are you using something like a RigBlaster?? The circuit above is
likely already built into the RigBlaster if that's what you are
using.
Greg? KO6TH
Max Donoghue wrote:
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Hi Greg
How do I specially key from the data jack?
