Icom IC-M127 User manual

VHF MARINE TRANSCEIVER
C-M127
Icom Inc.

IN CASE OF EMERGENCY
If your vessel requires assistance, contact other vessels and Or, transmit your distress call using digital selective calling on
the Coast Guard by sending a distress call on channel 16. channel 70 (the optional UX-130 psc unit must be installed),

TABLE OF CONTENTS
IN CASE OF EMERGENCY
TABLE OF CONTENTS
IMPORTANT
CAUTIONS...
1 OPERATING RULES ..
2 PANEL DESCRIPTION
@ Front panel ....
Function display
BASIC OPERATION
@ Receiving
@ Transmitting
@ Scan function
Call channel programming ..
Display backlighting
Channel names
DIGITAL SELECTIVE CALLING
@ General .....
@ Distress call transmission
All ships call transmission
Individual call transmission
@ Address input mode ..
lM Receiving DSC calls
5 OTHER FUNCTIONS
i Hailer operation
>
1 Intercom operation
‘Automatic fog horn
@ Internal speaker ON/OFF
'§ Displaying position
6 SET MODE ........ 26-30
Entering SET mode ..
SET mode items ...
CONNECTIONS AND MAINTENANCE
@ Unpacking ..
@ Additional requirements
x
8 OPTION INSTALLATION ......
'@ Removing/replacing the cas
@ Unit installation ...
9 TROUBLESHOOTING ...........
10 VHF MARINE CHANNEL LIST
11 SPECIFICATIONS
12 OPTIONS

IMPORTANT
READ ALL INSTRUCTIONS carefully and completely before using the transceiver.
SAVE THIS INSTRUCTION MANUAL—This instruction manual contains important
operating instructions for the IC-M127.
YOU MUST HAVE a DSC vessel ID in order to operate the optional DSC functions of the
transceiver. See your Dealer for details.
CAUTIONS
ZAXWARNING NEVER connect the transceiver to an AC
outlet. This may pose a fire hazard or result in an electric shock.
A\WARNING HIGH VOLTAGE! NEVER touch
the antenna or an internal antenna connector during trans-
mission. This may result in an electric shock or a burn,
NEVER connect the transceiver to a power source of more
than 16 V DC. This connection will ruin the transceiver.
WHEN INSTALLING THE DSC UNIT
NEVER transmit a distress call when your vessel does not
need immediate help. Distress calls can be used only in times
of emergency.
AVOID using or placing the transceiver in direct sunlight or
in areas with temperatures below —20°C (-4°F) or above
+60°C (+140°F).
DO NOT operate the transceiver without running the ves-
sel's engine. When your vessel's engine is OFF and the trans-
ceiver is transmitting, the vessel's battery will soon become
exhausted.
KEEP the transceiver out of the reach of children.
KEEP the transceiver and microphone at least 1 meter
away from your vessel's magnetic navigation compass.

© Priorities
* Read all rules and regulations pertaining to 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.
© Privacy
* Information overheard but not intended for you cannot law-
fully be used in any way.
* Indecent or profane language is prohibited.
© Radio licenses
SHIP STATION LICENSE
You must have a current radio station license before using the
transceiver. It is unlawful to operate a ship station which is not
licensed.
Inquire through your dealer or the appropriate government
agency for a Ship-Radiotelephone license. This license in-
cludes the call sign which is your craft's identification for radio
purposes.
OPERATING RULES
An FCC form 506 may be supplied with the IC-M127 U.S.A.
version. In this case, complete the form and send it to the
nearest FCC office.
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.
The Restricted Radiotelephone Operator Permit must be
posted near the transceiver or be kept with the operator. 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.
1

—P
i |
PANEL DESCRIPTION
@ Front panel
Function display (p. 4)
Speaker
@ CHANNEL SELECTOR [CHANNEL]
Selects an operating channel in the selected channel
group,
@ CHANNEL 16 SWITCH [16 * POS]
* Selects channel 16. (p. 6)
Push for 1 sec. to display your position (when a GPS re-
ceiver is connected). (p. 25)
© CALL CHANNEL SWITCH [9 * SCRM]
* Selects the call channel—the call channel is program-
mable, channel 9 being the default. (p. 6)
* Push and hold to activate the optional voice scrambler
function (optional UT-98 is required). (pgs. 38, 43)
@ CHANNEL/WEATHER CHANNEL SWITCH
[CH/WX + unc]
* Toggles between regular and weather channels. (p. 7)
* Selects channel groups in sequence when pushed for 1
sec. (p. 7)
© DUALTRI-WATCH SWITCH [DUAL * TRI] (p. 8)
* Activates dualwatch for checking channel 16.
* Push for 1 sec. to activate tri-watch for checking channel
16 and the call channel.
@ SCAN SWITCH [SCAN « TAG]
* Starts and stops normal or priority scan when tag chan-
nels are programmed. (p. 10)

* Push for 1 sec. to toggle the tag setting for the displayed
channel. (p. 10)
@ HIGH/LOW POWER SWITCH [HI/LO « DIM]
* Toggles between high and low output powers. (p. 9)
*While pushing, rotate the channel selector or push the
[V/A] switches on the microphone to adjust the display
and control/switch backlighting intensity. (p. 11)
© SQUELCH CONTROL [SQUELCH]
* Rotate clockwise to eliminate audio noise. (p. 8)
* Activates the built-in attenuator when rotated deep clock-
wise. (p.8)
@ POWER/VOLUME CONTROL [PWR/VOL] (p. 8)
* Push to turn power ON/OFF.
* Rotate to adjust the audio output.
@ HAILER/INTERCOM SWITCH [HLIIC « A.FOG]
*Selects/turns OFF the hailer and intercom functions,
(pgs. 21, 22)
* Push for 5 sec. to activate the auto fog horn function.
(p. 24)
@ INDIVIDUAL CALL SWITCH [INDV] (p. 16)
Push for 5 sec. to enter the individual call standby condi-
tion (when optional UX-130 is installed).
@ EMERGENCY SWITCH [EMER] (p. 14)
Push for 5 sec. to enter the distress call transmission
standby condition (when optional UX-130 is installed).
PANEL DESCRIPTION 2
® CHANNEL NAME SWITCH [NAME]
* Push to enter name input mode. (p. 12)
* Push for 5 sec. to enter the stand by condition for an “all
ships call" (when optional UX-130 is installed). (p. 15)
@ CHANNEL UP/DOWN SWITCHES [VJ/[4]
* Select an operating channel in the selected channel
group.
= These switches can be used instead of the transceiver's
channel selector.
@ HIGH/LOW POWER SWITCH [HI/LO]
The same function as the transceiver's front panel.
* Toggles between high and low output powers. (p. 9)
* While pushing, rotate the channel selector to adjust the display
and control/switch backlighting intensity. (p. 11)
|

2 PANEL DESCRIPTION
@ Function display
@ MODE INDICATORS (p. 7)
‘» “USA” shows USA channels are selected,
‘» “CAN” shows Canadian channels are selected.
‘» “INT” shows International channels are selected.
‘» “WX" shows weather channels are selected.
@ CALL CHANNEL INDICATOR
Appears when the call channel is selected. (p. 6)
© WEATHER ALERT INDICATOR
Indicates the weather alert function is activated. (p. 7)
@ CHANNEL INDICATOR
Shows the operating channel. (p. 7)
@ DUPLEX INDICATOR
Appears when the selected channel is a duplex channel.
@ TAG CHANNEL INDICATOR
Appears when the selected channel is set as a tag chan-
nel. (p. 10)
@ Low POWER INDICATOR
Shows that low output power is selected. (p. 9)

© LOW BATTERY INDICATOR
Appears when the vessel's battery voltage drops below
11 V. (p. 6)
@ VOICE SCRAMBLER INDICATOR
Appears while the optional voice scrambler is activated.
(p. 8)
@ SEND INDICATOR
Appears when DSC information has been transmitted.
(pgs. 13-20)
@ RECEIVE INDICATOR
Appears when DSC information has been received.
(pgs. 13-20)
@® TRANSMIT INDICATOR
Appears while transmitting. (p. 9)
® AUTO FOG HORN INDICATORS
Appear when the auto fog horn function is activated. The
number of indicators varies according to the selected fog
horn type. (p. 24)
@® s/AF INDICATOR
‘= Shows the relative signal strength while receiving.
‘» Shows whether high or low output power is selected
while transmitting. (pgs. 8, 9)
@ NMEA INDICATOR
Appears when NMEA devices (such as a GPS receiver)
are connected. (p. 35)
PANEL DESCRIPTION 2
@ ALPHANUMERIC READOUT
‘» Displays channel names during regular operation.
(p. 12)
‘» Displays position and UTC time when [16 *POS] is
pushed for 1 sec. (p. 25)
‘» Displays selected functions, DSC information, set mode
items, etc. depending on operation.
1

o |
3
@ Power ON
@ Push [PWR] in to turn power ON.
All display indications
appear briefly’.
BASIC OPERATION
*SCRM appears only when an optional
UT-08 is installed,
® Operate the transceiver as indicated in the following sec-
tions.
© Low voltage indicator
When “BATT” appears and flashes
as shown at right, the vessel's bat-
tery voltage has dropped below
11V, indicating there is a DC
power source problem, In this case, check your vessel's bat-
tery and DC power cable.
@ Channel selection
© Channel 16
Channel 16 is the distress channel. It is used for establishing
initial contact with another station and for emergency com-
munications. Channel 16 is monitored during dualwatch/tri-
watch. While standing by you are required to monitor channel
16.
- 6 |
© Call channel
The call channel is used to store your most often-used chan-
nel for quick recall. In addition, the call channel is monitored
during tri-watch, The default setting for the call channel is
channel 9, which is for pleasure boat use.
Push CG) rt
ves Lf
“CALL" indicates that the
call channel is selected.

© U.S.A., Canadian and international channels
There are 63 U.S.A., 62 Canadian and 59 international chan-
nels. These channel groups may be specified for the operat-
ing area.
@ Push [CH/WX] to select a regular channel.
If a weather channel appears, push [CH/WX] again.
® Rotate the channel selector to select a channel.
*“DUP” appears for duplex channels.
@ To change the channel group, push [CH/WX * U/I/C] for 1
sec,
+U.S.A., Canadian and international channels can be selected in
sequence,
U.S.A. channels
International
channels
Canadian channels
NOTE: When “DUP” appears in the display the se-
lected channel is a duplex channel. Duplex channels
are used for ship-to-coast communications.
When “DUP" does not appear in the display, the se-
lected channel is a simplex channel. Simplex chan-
Z, nels are used for ship-to-ship communications.
YX4489
BASIC OPERATION 3
© Weather channels
There are 10 weather channels. These are used for monitor-
ing NOAA (National Oceanographic and Atmospheric
Administration) weather broadcasts.
Push
once or twice
wv CONVENIENT
Weather alert function: NOAA broadcast stations transmit a
weather alert tone before important weather announcements.
When the weather alert function is turned ON (in SET mode),
and the IC-M127 receives an alert tone, the “ALT” indicator
flashes until any key is pushed.
This function can only be activated when a weather channel
is selected or during any scan (if the scan includes weather
channels). See “SET mode items” on p. 28.
* |

|
3 BASIC OPERATION
@ Receiving
@ Push [PWR] to turn power ON.
@ Rotate [SQUELCH] fully counterclockwise.
@ Rotate [VOLUME] to obtain a suitable listening level.
@ Rotate [SQUELCH] clockwise until the audio noise disap-
pears.
© Select the desired channel. See pgs. 6-7 for details.
+ When a signal is received:
+ The squelch opens;
Audio is emitted from the speaker;
$The S/RF indicator shows the re-
ceived signal strength.
© When an interrupting signal is received; rotate [SQUELCH]
deeply clockwise.
© Voice scrambler function
For confidential communications, use the optional voice
scrambler function. All members of your group must have the
UT-98 voice SCRAMBLER UNIT installed in order to communi-
cate using this function,
‘» Push [9 * SCRM] for 1 sec. to tog- me
gle the function ON and OFF. ose LY
*“SCRM” appears when the function is
ON.
* This function cannot be used on CH
16.
* Set the scramble code in SET mode in advance (p. 30).
© Dual/tri-watch functions
These functions allow you to conveniently check the distress
channel (ch 16) or, both the distress and call channel (ch 9;
programmable) while receiving another channel. When re-
ceiving a signal on one of these channels, the transceiver
stops on the channel until the signal disappears,
‘» Push [DUAL * TRI] momentarily for dualwatch,
i) ft
tow tow
ies Nee
“yin
JURA
lb
yarns + eee
Checking channel 16 Signals on channel 16 are
every 2 sec. monitored until they disappear.
‘= Push and hold [DUAL * TRI] for tri-watch.
noe
Joaun
Low
eal Ly. <n
“IRI 16
Checking channel 16 and When receiving a signal on the
channel, the call channel is
monitored while checking ch 16
the call channel every 2 sec.
Signals received on
channel 16have fen ST
priority. wil | pcm

=
eSSSSSSSSSSSSSSSSSSSSSSmmMSSSsSMMMMMMSMMSSsFse
B Transmitting
Before transmitting, read the call procedures at right.
@ Select an operating channel. See pgs. 6, 7 for details.
@ Push [HI/LO] to select transmit output power.
+ “LOW" appears when low output power is selected.
* High power cannot be selected on some channels. Refer to the
channel list on pgs. 40, 41.
© Push and hold the PTT switch to transmit.
+" GE" appears.
@ Speak into the microphone at your normal voice level.
Do not hold the microphone too closely to your mouth or speak
too loudly. This may distort the transmit signal.
© Release the PTT switch to receive.
Y IMPORTANT: In order to maximize the readability of your trans-
Y mitted signal, pause for a moment after pushing [PTT], hold the
Y
mictophone
15~20
cm
trom
your
mouth,
then
speak
into
the
mi-
Y crophone at an even, normal voice level.
WS
MOMENTARY HIGH POWER
On U.S.A. channels 13, 15 and 67, transmission using high
power is momentarily possible. To use high power, push
and hold [HI/LO] while transmitting.
BASIC OPERATION 3
CALL PROCEDURES
You must identify yourself when you transmit and you must
respect time limits.
1) Give your call sign each time you call another vessel or a
coast station. If you have no call sign, identify the station
by giving the vessel name and the name of the license.
2) Give your call sign at the end of each transmission that
lasts more than 3 minutes.
3) You must pause and give your call sign at least once
every 15 minutes during long ship-to-shore calls.
4) Keep your calls short (less than 3 minutes). Wait 2 min-
utes before repeating a call.
5) Unnecessary transmissions are not allowed.
TIME-OUT TIMER (U.S.A. version only)
The transceiver has a time-out timer function to prevent
continuous, long transmissions. Transmit is automatically
inhibited after 5 min. of continuous transmission.
ee!
=

3 BASIC OPERATION
@ Scan function
The transceiver has a high speed scan function for standing
by on utility signals. The scan speed is 8 channels/sec. (ex-
cept when the weather alert function is in use).
Two scan types are available: normal scan (scans all tag
channels in sequence) and priority scan (checks channel 16
while scanning and becomes dual watch while pausing on a
regular channel—except for channel 16). These scans can be
selected in SET mode (p. 28).
© Setting tag channels
You can specify channels as tag channels for efficient scan-
ning. Tag channels can be set for each channel group (USA,
CAN, INT) independently.
‘» Select the desired channel, then push and hold [SCAN*
TAG] for 1 sec. to toggle the tag setting.
! {=3-—— Appears when the channel is
(i specified as a tag channel.
un
V Clearing all tag channels:
While pushing [HI/LO], push and hold [SCAN « TAG] for 3 sec.
until the long beep becomes 2 short beeps.
* All tag channels in the selected channel group are released.
© Scan operation
@ Select the desired channel group (USA, CAN, INT) with
[CH/WXx * U//C].
+ When the weather alert function is in use, select the desired WX
channel in the display, then perform the above operation.
@ Push [SCAN] to start scanning.
+“N~ SCAN" appears when normal scan is selected in SET
mode.
+*P-5CAN” appears when priority scan is selected in SET
mode.
@ To stop the scan, push [SCAN] again.
+"N~ SCAN * or* P= SCAN” disappears,
Vv Scan resume tim
When a signal is detected, scan pauses until the signal dis-
appears or resumes after pausing 5 sec., according to the
SET mode setting. (p. 28)
v Confirming tag channels:
While operating scan, rotate [DIAL].
* Only tag channels are selected.
* Stop rotating [DIAL] to resume normal scan operation.
v Weather alert function:
When this function is turned ON (p. 28), any weather chan-
nels set as tag channels are monitored for alert tones during
scan. Refer to p. 7 for a description of weather alert.

BASIC OPERATION 3
@ Call channel programming SB Reh [6] gai program An fas
displayed channel as the call aa: Pa
The call channel switch, [9], is used to select channel 9, how- channel.
ever,
you
can
program
your
most
often-used
channels
in
each
*The
call
channel
number
and
channel group for quick recall. channel group stop flashing.
@ Push [CH/WX * U/I/C] for 1 sec. 1
one
or
more
times
to
select
uy
i
i
j
the
desired
channel
group
ie
Ma
Display
backlighting
(USA,
INT,
CAN)
to
be
pro-
—_______J
The
function
display
and
switches
can
be
backlit
for
better
vis-
grammed. ibility under low light conditions.
@ Push [9] to select the call PPro ;
channel of the selected chan- usa LY. While pushing [HI/LO * DIM], rotate the channel selector or
nel group. use [UPJ[DN] switches on the microphone to adjust the back-
*“CALL’ and the call channel num- lighting.
ber appear. | ‘* Backlighting can be set to 1 of 7 intensities or turned OFF.
@ While pushing [HI/LO] push [9] Se
to enter call channel write
mode.
*
Call
channel
number
and
chan-
DIMMER
7
DIMMER
OFF
nel group to be programmed flash. Backlighting set to brightest Backlighting turned OFF
@ Rotate the channel selector to a a
select the desired channel. cat
= CUA
ad 1 N
aS See |

3 BASIC OPERATION
@ Channel names
When shipped from the factory, the IC-M127 is programmed
with default names for each VHF marine channel (refer to the
VHF MARINE CHANNEL LIST on pgs. 40, 41). These de-
faults can be overwritten if desired.
@ Rotate [CHANNEL] to select a
channel to program.
@ Push [NAME] momentarily.
* The 1st character of the currently
programmed name flashes.
@ Rotate channel to select a
character.
Available characters
=~ (hyphen)
i
()
@® Push [HI/LO] to move to the
tight; then rotate [CHANNEL]
to select the next character.
*Pushing [SCAN] moves to the
left.
®Continue until the desired
characters have been se-
lected, then push [NAME] to
return to normal operation.

@ General
When an optional UX-130 osc unrr is installed, digital selec-
tive calling (or DSC) can be used via the transceiver. DSC is a
method of radio communications involving digital signals
rather than the more conventional method of voice communi-
cations. The advantage of using digital communications over
voice communications is that information (especially useful for
distress calls and other urgent matters) can be pre-pro-
grammed into a radio and transmitted accurately.
This sends distress information which hichides your vessel's ID (and Spe time data
when a GPS receiver is connected). Send under emergency conditions only. DSC acknowl-
edgement will be received from a coast station after making a distress call.
This is used to alert Coast stations (or other ships) when a vessel in distress is unable to do p.18
so. The IC-M127 can only receive this type of signal; not transmit. :
This is used for non-emergency situations. This signal includes information which allows a re- |Pgs.
ceiving transceiver to automatically select a specified channel for voice communication. 15, 18)
_—_ae
DIGITALSELECTIVECALLNG 4
In addition, when a GPS receiver (NMEA0183 ver. 1.5, 2.0 or
2.1) is connected, your vessel's position is transmitted to-
gether with the vessel's identity when making a distress call.
See p. 38 for unit installation.
This allows you to send a signal to a specific vessel only. The transceiver can store up to 10 des-
tination ID channels—select the desired ID in advance. Two kinds of acknowledgements (able to a
iP 4 ick pier 16, 19)
comply/unable to comply) are available (for sending or receiving) after an individual call.
This is used for announcement to all ships in the specified area—when a GPS receiver is p. 19
connected calls directed to areas other than yours are rejected. Receive only for the IC-M127.|""

4 DIGITAL SELECTIVE CALLING
Hf Distress call transmission
Y CAUTION: Distress calls may be transmitted under
ZY conditions of emergency only i.e. your vessel is in danger
7 of sinking and/or a person's life is in danger.
SSS
@® Push and hold [EMER] until
you hear 4 short beeps
change to one long beep.
* The display changes as at right.
® Push [PTT] to transmit the dis-
tress call.
DISTRESS
@ The transceiver remains on channel 70 until an acknowl-
edgement is received.
* When no acknowledgement is received, the distress call is re-
peated until an acknowledgement is received.
* To cancel this, turn power OFF then ON again.
* Calls to you other than distress acknowledgement cannot be re-
ceived.
@ When a distress acknowledge-
ment is received, emergency A Low
alarm sounds and channel 16 " Ro A a
is automatically selected.
*Push any key to cancel the
alarm.
® Transmit your distress call particulars by voice using the fol-
lowing procedure:
1. “MAYDAY.”
2. “THIS IS (name of your vessel).”
3. The 9-digit identity AND the calll sign (or other vessel iden-
tification).
4. Your vessel's position if DSC does not include it.
5. The nature of the distress and assistance required.
6. Any other information which might facilitate the rescue.
Y NOTE: When a GPS receiver (NMEA 0183) is connected,
your vessel's position is automatically transmitted with the
distress call.
SSS
NOTE: Acknowledgement of a DSC distress alert is nor-
mally made by coast stations only.
WSs

B All ships call transmission
Large ships use channel 70 as their “listening channel.” When
you want to announce a message to these ships, use the “all
ships call” function.
@ Select a simplex channel for
the traffic channel (for voice
communication after sending
the all ships call).
* Some ‘A’ channels (eg. channel 88A) cannot be used.
® Rotate [SQUELCH] clockwise until the audio noise disap-
pears.
@® Push and hold [NAME * ALL]
until you hear 4 short beeps
change to one long beep.
* The display changes as at right.
@ Push [PTT] momentarily to
transmit the all ships call.
* After transmission, the channel
set in step © above is selected.
® Push and hold [PTT] again to
send an announcement to all
ships.
Ie
SAP SHIP,
DIGITAL SELECTIVE CALLING 4
NOTE: Channel busy
When channel 70 is busy, the
all ships call is not transmit-
ted. The transceiver waits
until the channel is clear, then
transmits the call automati-
Y®IQAQAAN
g
<
NOTE: Error indication
When a transmission inhibited
channel (e.g. ch 70) is se-
lected for the traffic channel,
the display at right appears. In
YQOOGQ
TW ow
ree | ae
BUSY WAIT
This display appears
while the call is in
standby.
Ww
wm Low
u
DSC_ERROR
Z, this case, an appropriate channel must be selected.
15

4 DIGITAL SELECTIVE CALLING
Bf Individual call transmission
The individual call function allows you to transmit a DSC sig-
nal to a specific party only.
@ Set the ID code for the individual you wish to call in ad-
vance (see p. 17).
@ Select the traffic channel (for ri
voice communication after the
individual call is sent).
* Select a simplex acm (some SHIP~SHIP .
‘A’ channels cannot be used) for ship-to-ship contact.
* Select a duplex channel for ship-to-coast contact.
@ Rotate [SQUELCH] clockwise until the audio noise disap-
pears.
@ While pushing [INDV], rotate
the channel selector to select Ad. 0
the desired pre-programmed RESIPED ID
individual address. BES! is
® Continue pushing and holding
[INDV] until you hear 4 short
beeps change to one long PUSH PTT
beep.
* The display changes as at right.
© Push [PTT] momentarily to
transmit the individual call.
* ‘HIGH’ power is automatically se-
lected while transmitting the call.
@ Standby on channel 70 until an acknowledgement is re-
ceived.
® When the acknowledgement is =r)
received, the display changes ua f Hy tow
as
at
right.
=
7
“oop
oid
ABLE
ACK
|
*The channel set in step @ is se- [cna =]
lected,
© Push and hold [PTT] to com-
municate your message to the
va |
ABLE ACK
responding party.
Y NOTE: Unable to comply "Frm )
Y When the received acknowl- 4 ait} sow.
Z edgement includes “unable to UNABLE Ark
Z comply,” the message display ee eee
Y changes as at right. In such a mn Rov
ZG case, wait at least 5 min. be- un f
G fore re-transmitting the call. UNABLE ACK
NOTE: Channel busy error indication
The same as for the all ships call. Refer to the previous
page for details.
apr