Icom ic-m423g User manual

INSTRUCTION MANUAL
VHF MARINE TRANSCEIVERS
This device complies with Part 15 of the FCC
Rules. Operation is subject to the condition that
this device does not cause harmful interference.
|M423
|M423G
|M423GE
|M424
|M424G
IC-M423G

i
PREFACE
Thank you for choosing this Icom product.
This product is designed and built with Icom’s state of the art
technology and craftsmanship. With proper care, this product
should provide you with years of trouble-free operation.
DFEATURES
❍Simple operation with large keys
❍Easy to hear speaker
❍Built-in DSC meets ITU Class D requirement
❍Rugged waterproof construction
❍Optional COMMANDMIC
IV ™ (HM-195)
❍Easy to make an individual DSC calls using the optional
Class B AIS Transponder
❍Built-in GPS (For only the IC-M423G and IC-M424G)
❍Built-in GPS receiver with a supplied GPS antenna
(For only the IC-M423GE)
IMPORTANT
READ ALL INSTRUCTIONS carefully and completely
before using the transceiver.
SAVE THIS INSTRUCTION MANUAL — This in-
struction manual contains important operating instructions
for the transceiver.
EXPLICIT DEFINITIONS
WORD DEFINITION
RWARNING! Personal injury, fire hazard or electric
shock may occur.
CAUTION Equipment damage may occur.
NOTE
If disregarded, inconvenience only. No risk
of personal injury, fire or electric shock.
CLEAN THE TRANSCEIVER AND MICROPHONE THOR-
OUGHLY WITH FRESH WATER after exposure to saltwa-
ter, and dry it before operating. Otherwise, the transceiver’s
keys, switches and controllers may become unusable, due
to salt crystallization. Icom is not responsible for the destruction or damage to the
Icom transceiver, if the malfunction is because of:
• Force majeure, including, but not limited to, fires, earth-
quakes, storms, floods, lightnings, or other natural disas-
ters, disturbances, riots, war, or radioactive contamination.
• The use of Icom transceiver with any equipment that is not
manufactured or approved by Icom.
NOTE: If the transceiver’s waterproof protection appears
defective, carefully clean it with a soft, damp (fresh water)
cloth, then, dry it before operating.
The transceiver may lose its waterproof protection if the
case or connector cover is cracked or broken, or the trans-
ceiver has been dropped.

ii
IN CASE OF EMERGENCY
If your vessel requires assistance, contact other vessels and
the Coast Guard by sending a Distress call on Channel 16.
Or, make your Distress call using digital selective calling on
Channel 70.
USING CHANNEL 16
DISTRESS CALL PROCEDURE
1. “MAYDAY MAYDAY MAYDAY.”
2. “THIS IS ...............” (name of vessel).
3. Say your call sign or other description of the vessel (AND
9 digit DSC ID if you have one).
4. “LOCATED AT ...............” (your position).
5. State the nature of the distress and assistance required.
6. Give any other information which might facilitate the res-
cue.
USING DIGITAL SELECTIVE CALLING (Ch 70)
DISTRESS CALL PROCEDURE
1. While lifting up the key cover, hold down [DISTRESS]
for 3 seconds until you hear 3 short beeps and then one
long beep.
2. Wait for an acknowledgment on Channel 70 from a coast
station.
• After the acknowledgement is received, Channel 16 is auto-
matically selected.
3. Hold down [PTT], then transmit the appropriate informa-
tion as listed above.
INSTALLATION NOTE
Installation:
The installation of this equipment should be made in such a
manner as to respect the EC recommended electromagnetic
field exposure limits. (1999/519/EC)
The maximum RF power available from this device is 25
watts. The antenna should be installed as high as possible
for maximum efficiency and the installation height should be
at least 1.4 meters above any accessible position. In the case
where an antenna cannot be installed at a reasonable height,
then the transmitter should neither be continuously operated
for long periods if any person is within a distance of 1.4 me-
ters of the antenna, nor operated at all if any person is touch-
ing the antenna.
It is recommended that antenna of a maximum gain of 3 dB
are used. If higher gain antenna are required then please
contact your Icom distributor for revised installation recom-
mendations.
Operation:
The exposure to RF electromagnetic field is only applicable
when this device is transmitting. This exposure is naturally
reduced due to the nature of alternating periods of receiving
and transmitting. Keep your transmissions to the minimum
necessary.
Icom, Icom Inc. and Icom logo are registered trademarks of Icom Incorporated
(Japan) in Japan, the United States, the United Kingdom, Germany, France,
Spain, Russia, Australia, New Zealand, and/or other countries.
COMMANDMIC is a registered trademark of Icom Incorporated (Japan) in Ja-
pan and the United States.

iii
RADIO OPERATOR WARNING
WARNING
Icom requires the radio operator to meet the
FCC Requirements for Radio Frequency Expo-
sure. An omnidirectional antenna with gain not
greater than 9 dBi must be mounted a mini-
mum of 5 meters (measured from the lowest
point of the antenna) vertically above the main
deck and all possible personnel. This is the minimum safe
separation distance estimated to meet all RF exposure com-
pliance requirements. This 5 meter distance is based on the
FCC Safe Maximum Permissible Exposure (MPE) distance
of 3 meters added to the height of an adult (2 meters) and is
appropriate for all vessels.
For watercraft without suitable structures, the antenna must
be mounted so as to maintain a minimum of 1 meter verti-
cally between the antenna, (measured from the lowest point
of the antenna), to the heads of all persons AND all persons
must stay outside of the 3 meter MPE radius.
Do not transmit with radio and antenna when persons are
within the MPE radius of the antenna, unless such persons
(such as driver or radio operator) are shielded from antenna
field by a grounded metallic barrier. The MPE Radius is the
minimum distance from the antenna axis that person should
maintain in order to avoid RF exposure higher than the al-
lowable MPE level set by FCC.
FAILURE TO OBSERVE THESE LIMITS MAY ALLOW
THOSE WITHIN THE MPE RADIUS TO EXPERIENCE RF
RADIATION ABSORPTION WHICH EXCEEDS THE FCC
MAXIMUM PERMISSIBLE EXPOSURE (MPE) LIMIT.
IT IS THE RESPONSIBILITY OF THE RADIO OPERATOR
TO ENSURE THAT THE MAXIMUM PERMISSIBLE EXPO-
SURE LIMITS ARE OBSERVED AT ALL TIMES DURING
RADIO TRANSMISSION. THE RADIO OPERATOR IS TO
ENSURE THAT NO BYSTANDERS COME WITHIN THE
RADIUS OF THE MAXIMUM PERMISSIBLE EXPOSURE
LIMITS.
Determining MPE Radius
THE MAXIMUM PERMISSIBLE EXPOSURE (MPE) RA-
DIUS HAS BEEN ESTIMATED TO BE A RADIUS OF
ABOUT 3 M PER OET BULLETIN 65 OF THE FCC.
THIS ESTIMATE IS MADE ASSUMING THE MAXIMUM
POWER OF THE RADIO AND ANTENNAS WITH A MAXI-
MUM GAIN OF 9 dBi ARE USED FOR A SHIP MOUNTED
SYSTEM.

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AVERTISSEMENT POUR LES OPÉRATEURS RADIO
Icom exige que l’opérateur radio se conforme aux
exigences de la FCC en matière d’exposition aux
radiofréquences. Une antenne omnidirectionnelle
dont le gain ne dépasse pas 9 dBi doit être fixée
à une distance minimale de 5 mètres (mesurée
depuis le point le plus bas de l’antenne) verticale-
ment au-dessus du pont principal et de tout le personnel qui peut
s’y trouver. Il s’agit de la distance de sécurité minimale prévue pour
satisfaire aux exigences de conformité en matière d’exposition aux
RF. Cette distance de 5 mètres est établie en fonction de l’exposition
maximale admissible sécuritaire de 3 mètres établie par la FCC, à
laquelle on ajoute la hauteur d’un adulte (2 mètres); cette distance
convient pour tous les navires.
Dans le cas des embarcations sans structure convenable, l’antenne
doit être fixée de façon à maintenir une distance minimale de 1 mètre
verticalement entre cette antenne (mesurée depuis son point le plus
bas) et la tête de toute personne présente; toutes les personnes
présentes doivent se tenir à l’extérieur d’un rayon d’exposition maxi-
male admissible de 3 mètres.
Ne pas émettre à l’aide de la radio et de l’antenne lorsque des
personnes se trouvent à l’intérieur du rayon d’exposition maximale
admissible de cette antenne, à moins que ces personnes (comme
le conducteur ou l’opérateur radio) ne soient protégées du champ
de l’antenne par un écran métallique relié à la masse. Le rayon
d’exposition maximale admissible équivaut à la distance minimale
que cette personne doit maintenir entre elle et l’axe de l’antenne pour
éviter une exposition aux RF supérieure au niveau d’exposition maxi-
male admissible fixé par la FCC.
LE NON-RESPECT DE CES LIMITES PEUT CAUSER, POUR LES
PERSONNES SITUÉES DANS LE RAYON D’EXPOSITION MAXI-
MALE ADMISSIBLE, UNE ABSORPTION DE RAYONNEMENT
DE RF SUPÉRIEURE À L’EXPOSITION MAXIMALE ADMISSIBLE
FIXÉE PAR LA FCC.
L’OPÉRATEUR RADIO EST RESPONSABLE D’ASSURER QUE
LES LIMITES D’EXPOSITION MAXIMALE ADMISSIBLE SOIENT
RESPECTÉES EN TOUT TEMPS PENDANT LA TRANSMISSION
RADIO. L’OPÉRATEUR RADIO DOIT S’ASSURER QU’AUCUNE
PERSONNE PRÉSENTE NE SE SITUE À L’INTÉRIEUR DU RAY-
ON D’EXPOSITION MAXIMALE ADMISSIBLE.
Établir le rayon d’exposition maximale admissible
ON ESTIME QUE LE RAYON D’EXPOSITION MAXIMALE ADMIS-
SIBLE EST D’ENVIRON 3 M, TEL QUE STIPULÉ DANS LE BUL-
LETIN OET 65 DE LA FCC. CETTE DISTANCE ESTIMÉE TIENT
COMPTE D’UN SYSTÈME INSTALLÉ SUR UN NAVIRE UTIL-
ISANT LA PUISSANCE MAXIMALE DE LA RADIO ET DES AN-
TENNES DONT LE GAIN MAXIMAL EST DE 9 dBi.
AVERTISSEMENT

v
FCC INFORMATION
This equipment has been tested and found to comply with the
limits for a Class A digital device, pursuant to part 15 of the
FCC Rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment is
operated in a commercial environment.This equipment gener-
ates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction manual,
may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to
cause harmful interference in which case the user will be re-
quired to correct the interference at his own expense.
CAUTION: Changes or modifications to this transceiver, not
expressly approved by Icom Inc., could void your authority
to operate this transceiver under FCC regulations.
INFORMATION FCC
Cet équipement a été testé et reconnu conforme aux limites fixées
pour un appareil numérique de classe A, conformément au point 15 de
la réglementation FCC.Ces limites sont définies de façon à fournir une
protection raisonnable contre le brouillage préjudiciable lorsque cet
appareil est utilisé dans un environnement commercial. Cet équipe-
ment génère, utilise et peut émettre un rayonnement de fréquence ra-
dio. S’il n’a pas été installé conformément aux instructions, il peut par
ailleurs créer des interférences perturbant les communications radio.
L’utilisation de cet appareil dans une zone résidentielle peut provo-
quer un brouillage préjudiciable, auquel cas l’utilisateur sera tenu de
corriger la situation à ses frais.
MISE EN GARDE: Tout changement ou modification, non expressé-
ment approuvé par Icom Inc., peut annuler l’autorisation de l’utilisateur
à utiliser cet appareil conformément à la réglementation FCC.
NOTE
A WARNING STICKER is supplied with the USA version
transceiver.
To comply with FCC regulations, this sticker must be affixed in
such a location as to be readily seen from the operating con-
trols of the radio as in the diagram below. Make sure the chosen
location is clean and dry before applying the sticker.
EXAMPLE
WARNING.

vi
PRECAUTIONS
RWARNING! NEVER connect the transceiver to an AC
outlet. This may pose a fire hazard or result in an electric shock.
RWARNING! NEVER connect the transceiver to a pow-
er source of more than 16 V DC such as a 24 V DC. This
could cause a fire or damage the transceiver.
RWARNING! NEVER reverse the DC power cable po-
larity when connecting to a power source.This could damage
the transceiver.
RWARNING! NEVER cut the DC power cable between
the DC plug at the back of the transceiver and fuse holder. If
an incorrect connection is made after cutting, the transceiver
may be damaged.
RWARNING! NEVER operate the transceiver during a
lightning storm. It may result in an electric shock, cause a
fire or damage the transceiver. Always disconnect the power
souce and antenna before a storm.
CAUTION: NEVER place the transceiver where normal
operation of the vessel may be hindered or where it could
cause bodily injury.
KEEP the transceiver and microphone at least 1 m away
from the vessel’s magnetic navigation compass.
DO NOT use or place the transceiver in areas with tem-
peratures below –20°C (–4°F) or above +60°C (+140°F) or, in
areas subject to direct sunlight, such as the dashboard.
DO NOT use harsh solvents such as benzine or alcohol to
clean the transceiver, as they will damage the transceiver’s
surfaces. If the transceiver becomes dusty or dirty, wipe it
clean with a soft, dry cloth.
DO NOT disassemble or modify the transceiver for any rea-
son.
BE CAREFUL! The transceiver rear panel will become
hot when operating continuously for long periods of time.
Place the transceiver in a secure place to avoid inadvertent
use by children.
BE CAREFUL! The transceiver and the optional HM-195
commandmicIV™meet IPX7* requirements for waterproof
protection. However, once the transceiver has been dropped,
waterproof protection cannot be guaranteed because of pos-
sible damage to the transceiver’s case or the waterproof seal.
* Except for the DC power connector, NMEA In/Out leads, and AF
Out leads.

vii
PRÉCAUTIONS
RAVERTISSEMENT! NE JAMAIS connecter l’emetteur-
recepteur a une alimentation CA au risque de provoquer un in-
cendie ou un choc electrique.
R AVERTISSEMENT! NE JAMAIS brancher l'émetteur-
récepteur à une source d'alimentation de plus de 16 V CC,
comme une source de 24 V CC. Cela pourrait causer un in-
cendie ou endommager l'émetteur-récepteur.
R AVERTISSEMENT! NE JAMAIS inverser la po-
larité du câble d'alimentation CC en le branchant à la source
d'alimentation. Cela pourrait endommager l'émetteur-récepteur.
R AVERTISSEMENT! NE JAMAIS sectionner le câble
d'alimentation CC entre la prise CC de la face arrière de
l'émetteur-récepteur et le porte-fusible. L’émetteur-récepteur
peut être endommagé par la suite en cas de connexion inap-
propriée.
R AVERTISSEMENT! NE JAMAIS utiliser l'émetteur-
récepteur durant un orage. Cela risquerait de provoquer un
choc électrique, un incendie ou d'endommager l'émetteur-
récepteur. Toujours débrancher la source d'alimentation et
l'antenne avant une tempête.
MISE EN GARDE: NE JAMAIS installer l’émetteur-
récepteur à un emplacement où il pourrait gêner le fonc-
tionnement normal du navire ou provoquer des blessures
corporelles.
MAINTENIR l'émetteur-récepteur et le microphone à au
moins 1 mètre du compas de route magnétique du navire.
NE PAS utiliser ou placer l’émetteur-récepteur dans des
zones où la temperature est inférieure à –20° (–4°F) ou
supérieure à +60° (+140°F) ou dans des zones soumises
au rayonnement solaire direct, telles le tableau de bord.
NE PAS nettoyer l'appareil avec des solvants agressifs tels
que benzène ou alcool, susceptibles d'endommager les sur-
faces exposées du boîtier. En cas de dépôt de poussière ou
de salissures sur l'émetteur-récepteur, il faut l'essuyer avec
chiffon doux et sec.
NE PAS démonter ou modifier l'émetteur-récepteur pour
quelque raison que ce soit.
ATTENTION! La face arrière de l’émetteur-récepteur
chauffe en cas d’utilisation continue sur une longue durée.
Placer l’émetteur-récepteur hors de portée des enfants pour
éviter toute utilisation inopinée.
ATTENTION! L'émetteur-récepteur et l'accessoire option-
nel commandmicIVmc répondent aux exigences de l'indice
d'étanchéité IPX7*. Cependant, cette etancheite n’est plus
garantie apres une chute de l’appareil en raison des fissures
du boitier ou des dommages au joint d’etancheite et autres
dommages eventuels consecutifs a un tel incident.
* À l'exception du connecteur d'alimentation CC, des fils d'entrée ou
de sortie NMEA et des fils de sortie de fréquences audio.

viii
TABLE OF CONTENTS
PREFACE.............................................................................. i
IMPORTANT.......................................................................... i
EXPLICIT DEFINITIONS....................................................... i
IN CASE OF EMERGENCY................................................. ii
INSTALLATION NOTE.......................................................... ii
RADIO OPERATOR WARNING .......................................... iii
AVERTISSEMENT POUR LES OPÉRATEURS RADIO...... iv
FCC INFORMATION ............................................................v
INFORMATION FCC ............................................................ v
NOTE....................................................................................v
PRECAUTIONS................................................................... vi
PRÉCAUTIONS.................................................................. vii
1 OPERATING RULES.......................................................1
2 PANEL DESCRIPTION................................................2–8
■Front panel ...................................................................2
■Function display ...........................................................5
■Softkey function............................................................7
■Speaker Microphone....................................................8
3 PREPARATION..........................................................9–10
■Entering the MMSI code ..............................................9
■Entering the ATIS code
(For Dutch and German version transceivers) ...........10
4 BASIC OPERATION................................................11–18
■Selecting a Channel...................................................11
■Receiving and transmitting.........................................14
■Adjusting the volume and squelch levels ...................15
■Entering a Call channel data......................................16
■Entering a Channel name ..........................................16
■Microphone Lock function..........................................17
■Adjusting the Backlight level.......................................18
■Using the AquaQuake water draining function...........18
5 SCAN OPERATION.................................................19–20
■Scan types .................................................................19
■Setting Favorite channels...........................................20
■Starting a scan...........................................................20
6 DUALWATCH/TRI-WATCH............................................21
■Description.................................................................21
■Operation ...................................................................21

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TABLE OF CONTENTS (continued)
7 DSC OPERATION ...................................................22–70
■DSC address ID ........................................................22
■Entering position and time .........................................25
■Making a Distress call ................................................26
■Making DSC calls.......................................................32
■Receiving DSC calls ..................................................55
■Transmitted Call log....................................................62
■Received Call log.......................................................63
■DSC Settings .............................................................65
■Making an Individual call using an AIS transponder ..69
8 OTHER FUNCTIONS...............................................71–73
■Using the Intercom.....................................................71
■Using the RX Speaker................................................72
■Using the PA (Public Address) ...................................72
■Using the Horn...........................................................73
9 MENU SCREEN OPERATION ................................74–83
■Using the Menu screen..............................................74
■Menu screen items.....................................................75
■Radio Settings items..................................................76
■Configuration items ....................................................78
10 CONNECTIONS AND MAINTENANCE..................84–90
■Connections...............................................................84
■Antenna......................................................................86
■Fuse replacement ......................................................86
■Cleaning.....................................................................86
■Supplied accessories.................................................86
■Mounting the transceiver............................................87
■MB-132 installation ....................................................88
■Microphone installation ..............................................89
11 SPECIFICATIONS AND OPTIONS .........................91–92
■Specifications.............................................................91
■Options.......................................................................92
12 CHANNEL LIST.............................................................93
13 TROUBLESHOOTING...................................................94
14 TEMPLATE ....................................................................95
15 INFORMATION ..............................................................97
■About CE and DOC....................................................97
■Disposal .....................................................................97
INDEX.................................................................................98

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1
OPERATING RULES
DPriorities
• Read all rules and regulations pertaining to call priorities,
and keep an up-to-date copy handy. Safety and distress
calls take priority over all others.
• You must monitor Channel 16 when you are not operating
on another channel.
• False or fraudulent distress calls are prohibited under law.
DPrivacy
• Information overheard, but not intended for you, cannot law-
fully be used in any way.
• Indecent or profane language is prohibited.
DRadio licenses
(1) SHIP STATION LICENSE
You may require a current radio station license before using
the transceiver. It is unlawful to operate a ship station which is
not licensed, but required to be.
If required, contact your dealer or the appropriate govern-
ment agency for a Ship-Radiotelephone license application.
This government-issued license states the call sign which is
your craft’s identification for radio purposes.
(2) OPERATOR’S LICENSE
A Restricted Radiotelephone Operator Permit is the license
most often held by small vessel radio operators when a radio
is not required for safety purposes.
If required, the Restricted Radiotelephone Operator Permit
must be posted or kept with the operator. If required, only a
licensed radio operator may operate a transceiver.
However, non-licensed individuals may talk over a transceiver
if a licensed operator starts, supervises, ends the call and
makes the necessary log entries.
A current copy of the applicable government rules and regu-
lations is only required to be on hand for vessels in which a
radio telephone is compulsory. However, even if you are not
required to have these on hand it is your responsibility to be
thoroughly acquainted with all pertinent rules and regulations.
NOTE: Even though the transceiver is capable of opera-
tion on VHF marine channels 1021, 1023, 1081, 1082 and
1083, according to FCC regulations these simplex chan-
nels cannot be lawfully used by the general population in
USA waters.
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16

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PANEL DESCRIPTION
2
Front panel
t
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q
Function display (p. 5)Speaker
qDISTRESS KEY [DISTRESS] (pp. 26, 27)
Hold down for 3 seconds to make a Distress call.
wENTER KEY [ENT] (pp. 9, 12, 74)
Push to set the entered data, selected item, and so on.
eLEFT AND RIGHT KEYS [Ω]/[≈]
Push to change to the previous or next key function that
is assigned to the softkeys. (p. 7)
Push to select the desired character or number in the
table while in the channel name, position, MMSI code
entry mode, and so on. (pp. 9, 16, 25)
r
UP AND DOWN/CHANNEL SELECT KEYS [∫•CH]/[√•CH]
Push to select the operating channels, Menu items,
Menu settings, and so on. (pp. 14, 74)
While scanning, push to check Favorite channels,
change the scanning direction or manually resume a
scan. (p. 20)
tCLEAR KEY [CLEAR]
(pp. 9 , 16 , 74 )
Push to cancel the entered data, or to return to the previ-
ous screen.
yMENU KEY [MENU]
(p. 74 )
Push to enter or exit the Menu screen.
uVOLUME AND SQUELCH SWITCH/POWER SWITCH
[VOL/SQL•PWR]
When the power is OFF, hold down for 1 second to turn
ON power. (p. 14)
Hold down for 1 second to turn OFF power.
When the power is ON, push to enter the volume level
adjustment mode.* (p. 15)
• Each push of this switch toggles the mode between the vol-
ume level adjustment, squelch threshold level adjustment,
operating channel selection, and the LCD and key backlight
brightness adjustment, if assigned.
Rotate to adjust the volume level.* (p. 15)
*The desired function can be assigned in the Menu screen.

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PANEL DESCRIPTION
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iCHANNEL 16/CALL CHANNEL KEY [16/C]
Push to select Channel 16. (p. 11)
Hold down for 1 second to select the Call channel. (p. 11 )
•“CALL” is displayed when the Call channel is selected.
 When the Call channel is selected, hold down for 3 sec-
onds to enter Call channel entry mode. (p. 16 )
oSOFTKEYS
Desired functions as described below can be assigned in
the Menu screen.
Distress Call [ ]
(For only USA version transceivers.)
Push to enter “DISTRESS CALL” in the DSC menu to se-
lect the nature of the call, and then to make a call.
DSC [ ] (For only USA version transceivers.)
Push to enter the DSC menu to compose a DSC call.
Scan [ ](p. 20)
Push to start or stop a Normal or Priority scan.
Dualwatch/Tri-watch [ ](p. 21)
Push to start Dualwatch or Tri-watch.
Push to stop Dualwatch or Tri-watch when either is ac-
tivated.
High/Low [ ](p. 14)
Push to set the power to high or low.
• Some channels are set to only low power.
Channel/Weather channel [ ]* (pp. 11, 13)
Push to selects and toggles the regular channel and
Weather channel.
*For only the USA and Australian version transceivers.
Channel [ ]* (p. 11)
Push to select a regular channel.
* For only the IC-M423, IC-M423G, and IC-M423GE except for
Australian version transceivers.
Public address [ ] (p. 72)
Push to enter the PA (Public Address) mode.
RX Speaker [ ](p. 72)
Push to turn the RX Speaker mode ON or OFF.
Horn [ ](p. 73)
Push to enter the Horn mode.
Intercom [ ](p. 71)
Push to enter the Intercom mode.
LO/DX [ ]* (p. 14)
Push to turn the Attenuator function ON or OFF.
• “LOCAL” is displayed when the Attenuator function is ON.
*For only the USA and Australian version transceivers.
AquaQuake [ ] (p. 18)
Holding down to activate the AquaQuake to clear water
away from the speaker grill.

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2PANEL DESCRIPTION
Front panel (Continued)
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qFunction display (p. 5)Speaker
Favorite channel [ ] (p. 20)
Push to set or clear the displayed channel as a Favorite
(Tag) channel.
Hold down for 3 seconds to clear or set all Favorite
channels in the selected channel group.
Name [ ](p. 16)
Push to enter the channel name entry mode.
Backlight [ ] (p. 18)
Push to enter the LCD and key backlight brightness ad-
justment mode.
• While in the adjustment mode, push [∫]/[√]/[Ω]/[≈] or rotate Dial
to adjust the brightness of the LCD and key backlight.
Log [ ] (p. 63)
Push to enter “RCVD CALL LOG” in the DSC CALLS menu.

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PANEL DESCRIPTION
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Function display
!9
!5
!7
!8
!6
qw ietr!0you
!2
!3
!4
!1
qBUSY/TRANSMIT ICON (p. 14)
“ ” is displayed when receiving a signal or when
the squelch is open.
“” is displayed while transmitting.
wPOWER ICON (p. 14)
“25W” is displayed when high power is selected.
“1W” is displayed when low power is selected.
eRX SPEAKER ICON (p. 72)
Displayed while in the RX Speaker mode.
rCHANNEL GROUP ICON (p. 12)
Shows which channel group is selected, INT, USA,
CAN, ATIS or DSC, depending on the version.
“WX” is displayed when the weather channel is select-
ed.*
*For only USA and Australian version transceivers.
tCALL CHANNEL ICON (p. 11)
Displayed when the Call channel is selected.
yDUPLEX ICON (p. 12)
Displayed when a duplex channel is selected.
uFAVORITE CHANNEL ICON (p. 20)
Displayed when a Favorite (Tag) channel is selected.
iMESSAGE ICON (p. 63)
Blinks when there is an unread DSC message.
oGPS ICON
Stays ON when the built-in GPS receiver* or an exter-
nal GPS receiver is receiving valid position data.
*For only IC-M423G, IC-M423GE, and IC-M424G.
Blinks when searching for valid position data.
!0 SWITCH ICON (p. 66)
Displayed when the “CH 16 SWITCH” in DSC Settings is
set to OFF.

6
2PANEL DESCRIPTION
Function display (Continued)
!9
!5
!7
!8
!6
qw iet
r!
0you
!2
!3
!4
!1
!1 RT (Radio Telephone) ICON
(For only USA version transceivers.)
Displayed while in the Radio Telephone mode.
• The Radio Telephone mode is terminated if no operation occurs
during the preset of time.
• The icon is displayed if the “RT Indicator:” item in the RADIO
SET menu is set to “ON.” (p. 77)
!2 LOW BATTERY ICON
Blinks when the battery voltage drops to approximately
10 V DC or less.
!3 CHANNEL NUMBER READOUT
Shows the selected operating channel number.
!4 CHANNEL NAME FIELD
The channel name is displayed, if entered. (p. 16)
!5 KEY ICON (p. 7)
Shows the preset function of the softkeys on the front panel.
!6 TIME ZONE INDICATOR
Shows the current time when GPS data is received, or
the time is manually entered.
• When the GPS current time is invalid, “??” will blink every
2 seconds instead of the current time. After 23.5 hours has
passed, “NO TIME” is displayed.
• “??” will blink every 2 seconds instead of the current time,
after 4 hours* have passed from when the time was manu-
ally entered. The manually entered time is held for only 23.5
hours, and after that, “NO TIME” is displayed.
*3 hours and 59 minutes for USA version.
“LOCAL” is displayed when the offset time is set.
“MNL”
is displayed when the time is manually entered .
“UTC”
is displayed when the GGA, GLL or GNS GPS
sentence format is included in the GPS signal.
The date information is displayed when the RMC GPS
sentence format is included in the GPS signal.
“NO TIME”
is displayed when no GPS receiver is con-
nected, and no time is manually entered.
NOTE for the IC-M423 and IC-M424:
These models do not come with a built-in GPS receiver.
Therefore an external GPS receiver needs to be con-
nected, or the time needs to be manually entered for
the time zone indicator to be displayed.

7
2
PANEL DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
!7 POSITION INDICATOR
 Shows the current position when position data is re-
ceived, or the position is manually entered.
• When the GPS position is invalid, “??” may blink every 2 sec-
onds instead of position. The last position is held for only
23.5 hours, and after that, “NO POSITION” is displayed.
• “??” will blink every 2 seconds instead of position, after 4
hours* have passed from the time when the position is manu-
ally entered.The manually entered position is held for only 23.5
hours, and after that, “NO POSITION” is displayed.
*3 hours and 59 minutes for USA version.
 “NO POSITION” is displayed when no GPS receiver is
connected, and no position is manually entered.
!8 SCAN INDICATOR
“SCAN 16” is displayed during a Priority scan; “SCAN”
is displayed during a Normal scan. (p. 20)
“DUAL 16” is displayed during Dualwatch; “TRI 16” is
displayed during Tri-watch. (p. 20)
!9 LOCAL ICON* (p. 14)
Displayed when the Attenuator function is turned ON.
*For only USA and Australian version transceivers.
Softkey function
Various functions can be assigned to the softkeys. When a
key function is assigned, the key icon is displayed above the
softkey, as shown below.
DSoftkey function selection
When “Ω” or “≈” is displayed beside the key icon, sequentially
pushing [Ω]/[≈] displays the previous or the next key function
that is assigned to the softkey.
Push
Push
*
*Push this key to start
and stop scan.
The order of the key icons may differ, depending on the
version or presetting.

8
2PANEL DESCRIPTION
Speaker Microphone
Microphone
Speaker
IC-M423G/IC-M423GE
/IC-M424G IC-M423/IC-M424
w
q
e
r
qPTT [PTT]
Hold down to transmit, release to receive. (p. 14)
wCHANNEL UP/DOWN KEYS [Y]/[Z]
Push either key to check Favorite channels, change scan-
ning direction or manually resumes a scan. (pp. 14, 20)
eTRANSMIT POWER KEY [H/L]*
Push to toggle the power high or low. (p. 14)
• Some channels are set to only low power.
While holding down [H/L], turn ON the power to turn the
Microphone Lock function ON or OFF. (p. 17)
*[HI/LO] is printed for the IC-M423/IC-M424.
rCHANNEL 16/CALL CHANNEL KEY [16/C]
Push to select Channel 16. (p. 11)
Hold down for 1 second to select the Call channel. (p. 11 )
•The “CALL” icon is displayed when the Call channel is se-
lected.
*For only the IC-M423G, IC-M423GE, and IC-M424G.

9
3
PREPARATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Entering the MMSI code
The 9 digit MMSI (Maritime Mobile Service Identity: DSC self
ID) code can be entered at power ON.
This initial code setting can be made only once.
After being set, it can be changed by only your dealer
or distributor. If your MMSI code has already been en-
tered, the following steps are not necessary.
qHold down [PWR](Dial) to turn ON the power.
• Three short beeps sound, and “NO DSC MMSI” is displayed.
wPush [ENT] to start the MMSI code entry.
• Push [CLEAR] twice to cancel the entry, and go to the normal
operating screen. In this case, the transceiver cannot make a
DSC call.To enter the MMSI code, turn OFF the power, then turn
it ON again.
eEnter your MMSI code in the following way:
• Select a desired number using Dial, or [∫]/[√]/[Ω]/[≈].
• Push [ENT] or Dial to set it.
• To move the cursor, select either arrow, “←” or “→,” then push
[ENT] or Dial.
rRepeat step eto enter all 9 digits.
tAfter entering the 9 digit code, “FINISH” is automatically
selected, and then push [ENT] or Dial to set it.
yThe “MMSI CONFIRMATION” screen is displayed.
uEnter your MMSI code again for confirmation.
• Enter in the same way as steps ethrough t.
iWhen your MMSI code entry is successfully completed,
the screen as shown below is briefly displayed.
• After that, the normal operating screen is displayed.
The entered MMSI code can be checked in the MENU screen.
(p. 74)
NOTE: Depending on the transceiver version, the ATIS
code entry may be required after entering the MMSI code.
See the next page for details.

10
3PREPARATION
The 10 digit ATIS (Automatic Transmitter Identification Sys-
tem) code can be entered at power ON.
This initial code setting can be made only once.
After being set, it can be changed by only your dealer
or distributor. If your ATIS code has already been en-
tered, the following steps are not necessary.
qAfter entered the MMSI code, “Push [ENT] to Register
Your ATIS” is displayed.
wPush [ENT] to start entering the ATIS code.
• Push [CLEAR] twice to cancel the entry, and go to the normal
operating mode. In this case, the ATIS function is disabled. To
enter the ATIS code, turn OFF the power, then turn it ON again.
eEnter your ATIS code in the following manner:
• Select a desired number using Dial, or [∫]/[√]/[Ω]/[≈].
• Push [ENT] or Dial to set it.
• To move the cursor, select either arrow, “←” or “→,” then push
[ENT] or Dial.
rRepeat step eto enter all 10 digits.
tAfter entering the 10 digit code, “FINISH” is automatically
selected, and then push [ENT] or Dial to set it.
yThe “ATIS CONFIRMATION” screen is displayed.
uEnter your ATIS code again for confirmation.
• Enter in the same manner as steps ethrough t.
iWhen your ATIS code is successfully entered, the screen
as shown below is briefly displayed.
• After that, the normal operating screen is displayed.
The entered ATIS code can be checked in the MENU screen.
(p. 74)
* Presetting is required to use the ATIS mode in the German version.
Contact your dealer for details.
Entering the ATIS code (For Dutch and German* version transceivers)