The AI1 microphone adapter cable is created to adapt the MC1 microphone cable (which is a standard 3,5mm mono) to match the connector on your Icom radio.
The mic cable is plugged into the 3,5mm female mono jack on the adapter cable. The mic connector on the adapter cable then plugs into the microphone jack on your transceiver.
The 1/4 in. the female jack on the adapter cable is for connecting a Push-To-Talk (PTT) footswitch or hand switch. Even without a PTT footswitch or hand switch, your radio can still
be used in VOX mode.
The adapter does not come as a part of the NC-1 headset and is sold separately.