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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
"Orval Fairbairn" <orfairbairn@earthlink.net> wrote in message
news:orfairbairn-EB24AD.09301502112005@news1.east.earthlink.net...
> In article <Xns97025413659A9GaryG@216.196.97.131>,
> Gary G <gary@NOSPAMgilbert-land.com> 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.
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Re: Wiring diagram for mic?
