Alinco DR-138 - Manual (Page 14)

6
2
Microphone
connector
Microphone [EMS-74] Antenna
External speaker
Initial Installation
Microphone
For voice communications, connect a provided microphone into
the socket on the front of the main unit. Turn the ring firmly on the
plug until it locks. Attach the supplied microphone hanger in an
appropriate location using the screws included in the screw set.