On Thu, 03 Nov 2005 09:18:42 -0600, Gary G
wrote:

With all due respect - why is it that you care about that.
If it doesn't concern you, why bother?
I don't see that many people agree with you on that.

Judge and Jury convened and departed in your mind already?

No - I did not get an answer.

Most thankful regards,

Gary

"With all due respect" - perhaps after posting in multiple groups,
you neglected to go back and check them all for "an answer".

It sure looks like you got an answer to me, just not in RAM.

If you think you'll get anywhere twisting Jim's tail, knock yourself
out. The really, really funny thing is, he's probably the best 'group
resource available for concise, accurate answers to GA
avionics-related questions.

see below;

TC


From RAH, not RAM

On Wed, 02 Nov 2005 07:15:48 -0600, Gary G
wrote:

Would anyone be kind enough to point me to a wiring
diagram for a general aviation radio?

I need to know the pinout configurations and voltage
for the mic connection.

Thank you and regards in advace!

Gary

Same thread, also from RAH

On Wed, 02 Nov 2005 14:30:17 GMT, Orval Fairbairn
wrote:

There is VERY low voltage involved -- #22 AWG (shielded) wire will
suffice.

There are three hookups to the jack: Mike Key, Mike Audio and Mike Ring.

Ring goes to Ground

Key goes to a switch, which grounds the key circuit. This activates the
transmit relay in the radio.

Mike Audio passes straight through to the radio audio circuit and
carries the voice. This wire should be shielded, to reduce EM
interference.

IIRC, the audio is the tip of the jack; the key is the next position on
the jack. Ground is the outer (long) part of the jack. Check with a
circuit tester.

Still in the same thread...

On Wed, 2 Nov 2005 09:07:30 -0800, "RST Engineering"
wrote:

Not quite, Orval. From the leading edge of the male connector (microphone
end as opposed to the aircraft end) the sections of the plug are tip, ring,
and shell.

Grounding the tip places the transceiver in the transmit mode; ungrounding
it (open) leaves the transceiver in the receive mode.

The ring carries the microphone audio (more later).

The shell is airframe or chassis ground.


The mic audio line coming from the transceiver is a current source that is
intended to provide a 300 ohm mic element with about 10 mA. Generally this
is a simple resistor fed from a quiet regulated supply inside the
transceiver. I usually use the +10 volt supply and a 680 ohm resistor. The
microphone circuit is designed to emulate a carbon microphone (variable
resistance with audio) and will give somewhere between half a volt and a
volt peak to peak with normal mic audio.


Jim