30OTHER FUNCTIONS7 Intercom operationThe optional Intercom function allows you to talk to the deckfrom the cabin. The optional HM-157 COMMANDMIC II™ isrequired for Intercom operation.Connect an optional HM-157 as described on pgs. 35, 52.• Transmitting is impossible during Intercom operation.• The received signal is muted during Intercom operation.q Push [LO/DX•IC] for 1 sec. to enter Intercom mode.• The HM-157 power is automatically turned ON, even if the poweris OFF.w Push [LO/DX•IC] for 1 sec. again to call up the HM-157side.• The transceiver and the HM-157 emit call beeps.e Push and hold [PTT] and speak at a normal voice levelinto the microphone.• “ ” or “ ” appears on the caller or listener function dis-play, respectively.• To adjust the IC-M422’s speaker output level, rotate [VOL].• To adjust the HM-157’s speaker output level, push [Y] or [Z]after pushing [VOL• PA/RX ] on the HM-157.r After releasing [PTT] you can hear the response throughthe speaker.t To return to the normal operation, push [LO/DX•IC ] mo-mentarily.• [16•9] and [DISTRESS] keys are also available.• While in the Intercom mode, the transceiver functions(transmit and receive) are interrupted. If the transceiveris in transmit condition, the Intercom function is not avail-able.• When a DSC call is received, “DSC” appears and theDSC message is displayed at the channel comment indi-cator after the Intercom use is finished.• When a WX alert is received, “WX ALT” blinks and abeep sounds. The WX alert sounds after the Intercomuse is finished.HM-157 (listener)IC-M422 (caller)DIMHM-157IC-M422

OPERATING RULES

panel description

I Microphone

I Function display

basic operation

I Receiving and transmitting

I Call channel programming

I Channel comments

scan operation

I Setting TAG channels

I Operation

I MMSI code check

I DSC Address ID

i position indication

i distress call

I Transmitting DSC calls

dsc operation

transmitting a group call

transmitting an all ships call

I Receiving DSC calls

receiving a group call

other functions

I Public Address (PA) function

I Set mode items

set mode

I Fuse replacement

I Optional MB-69 installation

TROUBLESHOOTING

SPECIFICATIONS AND OPTIONS

i panel description

I Channel selection

I Lock functions

I Display backlight

I Starting a scan

I Set mode programming

I Intercom operation

I HM-157 supplied accessories

I Installation

CHANNEL LIST

TEMPLATE

Icom IC-M422 Instruction Manual

IC-M422

MAIN UNIT

LOGIC BOARD

TRANSMITTER CIRCUITS

PLL CIRCUITS

POWER SUPPLY CIRCUITS

PREPARATION

FREQUENCY ADJUSTMENT

TRANSMIT ADJUSTMENT

RECEIVE ADJUSTMENT

front unit

SQL BOARD

MECHANICAL PARTS AND DISASSEMBLY

VOLTAGE DIAGRAM