That's because it ain't $120 worth of jacks and wire. It is $120 worth of
amplifier that takes those few millivolts of microphone audio, uses the bias
voltage coming down the aircraft radio mic audio line, smooths that voltage
into a working voltage for an amplifier, and provides an amplifier that
takes those millivolts to volts to drive the aircraft radio.

Jim




"Richard Riley" wrote in message
...
On Mon, 02 Oct 2006 02:33:18 GMT, "Cy Galley"
wrote:

I believe Comtronics has a web site. Why not ask the maker?

They want $120 for $15 worth of jacks and 3 feet of wire. They're
free to charge that much - but I'm free to try making one on my own.
So I'm going to give it a shot.