[ICOM] IC-703 microphone connector question

[Bill Buoy]

This is a question for one of the service gurus out there. I am putting
together a headset-microphone and PTT switch accessory for an upcoming
contest. Since the station is portable/mobile, one connection for the
headset and mic would be more convenient.

The microphone connector pin out on the 703 is as follows:

1-+8V (10 ma. max)
2-Frequency up/down
3-Audio
4-PTT
5-Mic ground
6-Mic in
7-Ground
8-Squelch

Pin 3 is described as Audio. I traced the obvious connections using the
schematic in the service manual and found that this signal is derived from
the audio output to the speaker through a resistor, before the speaker
on-off switch. The same signal appears to be available on both the front and
rear mic connectors. I couldn't see anyplace else that uses this signal.

Will loading this signal with a low-impedance headset cause any problems in
the radio? Or do I need to put a small buffer amp in the headset/mic
adapter?

Thanks and 73,

Bill Buoy

Web page http://www.geocities.com/buoy@sbcglobal.net/home.html
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