Icom Marine Single Pin M25 & M93
01 November 2015

This wiring plan is for Icom Marine radios with a single 3.5mm threaded socket.
3.5mm Pin with screw locking thread.
Gnd.
Common Ground for Mic, Speaker and Mic
Mic & PTT
Electret Mics only connected here. When Mic is connected via PTT to Ground the radio transmits. (Mic and PTT are in series).
EXT DET
Ground this pin for headset use. Switches the audio to the headset.
Spk
Speaker Out
Icom M25, M93D and M73.
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