Aurora Audio GTM822-2GN - Manual (Page 14)

Connecting the Talk-back facility :-
The external talk-back microphone and
“press to talk” switch are connected via
the male 9 pin D sub connector on the
rear of the master unit.
The wiring of the mating female D sub,
viewed from the wiring side, is shown in
the illustration. Any type of microphone
can be used as the amplifier provides
phantom power and has a built in
compressor-limiter.
The four spare pins in this connector carry the signals to drive two external VU
meters that will require 3600 ohm series resistors (or adjust to suit).
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