Standard Horizon Marine Tranciever GX1280S Operating Instructions

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7  DIGITAL SELECTIVE CALLING
7.1  GENERAL
WARNING
This radio is designed to generate a digital maritime distress and safety
call to facilitate search and rescue. To be effective as a safety device,
this equipment must be used only within communication range of a shore-
based VHF marine channel 70 distress and safety watch system. The
range of signal may vary but under normal conditions should be ap-
proximately 20 nautical miles.
Digital Selective Calling is a semi-automated method of establishing a radio
call, it has been designated by the International Maritime Organization (IMO)
as an international standard for establishing VHF, MF and HF radio calls. It
has also been designated as part of the Global Maritime Distress and Safety
System (GMDSS). It is planned that DSC will eventually replace aural watches
on distress frequencies and will be used to announce routine and urgent
maritime safety information broadcasts.
This new system allows mariners to instantly send a distress call with GPS
position (when connected to the transceiver) to the US Coast Guard and
other vessels within range of the transmission. DSC will also allow mariners
to initiate or receive Distress, Urgency, Safety, Routine, POSITION RE-
QUEST, POSITION SEND, and Group calls to or from another vessel
equipped with a DSC transceiver.
7.2  DSC SCAN
When the radio is shipped from the factory it is programmed so CH70 (the
DSC channel) is scanned at all times. A selection is provided in the SETUP
MENU to disable the DSC SCAN. Turning off DSC SCAN will disable the
radio from receiving DSC calls (i.e.: Distress Call, Individual Call, All Ships
Call, and Position Requests). If you want to use any of the functions the
selection must be left ON.
To Change DSC SCAN Method:
1. Press and hold down the [
CALL/SET]
 key until
“RADIO SETUP” menu appears.
2. Turn the CHANNEL selector knob to select “DSC
SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “DSC 
						

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SCAN” with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key.
5. Turn the CHANNEL selector knob to select “ON”or
“OFF.”
6. Press the [
CALL/SET]
 key to store the selected
setting.
7. To exit this menu and return to radio operation
mode press the [
16/9]
 key.
7.3  USCG DSC WATCH
The USCG has plans to upgrade its VHF National Distress System (expected
by 2005), so at the time of printing only larger vessels that are required to
carry VHF DSC radios will be able to hear your distress transmission.
7.3.1  Maritime Mobile Service Identity (
MMSI)
What is an MMSI?
An MMSI is a nine digit number used on Marine Transceivers capable of using
Digital Selective Calling (DSC). This number is used like a telephone number
to selectively call other vessels.
THIS NUMBER MUST BE PROGRAMMED INTO THE RADIO TO OPER-
ATE THE MATRIX DSC FUCTIONS.
How can I obtain an MMSI assignment?
Boat US offers free MMSI numbers. Visit the following to register:
http://www.boatus.com/mmsi/.
7.3.2 Programming the MMSI
NOTE
User MMSI can be input only twice. If the user tries to input MMSI more
than twice, the radio will show the display on the right.  If the user needs
to change the MMSI more than twice, the transceiver will have to be
sent to Factory Service.  Refer to the section 10.2 FACTORY SERVICE.
1. Press and hold down the [
CALL/SET]
 key until
the “RADIO SETUP” menu appears.
2. Turn the CHANNEL selector knob to the left to
select “DSC SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “USER
MMSI” with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key. The “User MMSI” num- 
						

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ber will appear, and the first space will flash.
5. Select first number of your MMSI, then press the
[
CALL/SET]
 key to step to the next number.
6. Repeat step 5 to set your MMSI (up to nine digits).
7. When finished programming the number, press
and hold the [
CALL/SET]
 key to store the number
in memory.
8. To exit this menu and return to radio operation mode press the [
16/9]
 key.
7.4  ADDITIONAL DIGITAL SELECTIVE CALLING INFORMATION
For additional information the USCG has an excellent site that should be
visited at 
www.navcen.uscg.mil/marcoms/gmdss/dsc.html.
7.5  DSC DISTRESS CALL
The MATRIX is capable of transmitting and receiving DSC Distress mes-
sages to all DSC radios. The MATRIX may be connected to a GPS to also
transmit the Latitude, Longitude of the vessel.
7.5.1 Transmitting A DSC Distress Call
NOTE
To be able to transmit a DSC distress call a MMSI number must be
programmed, refer to section 7.3.2 Programming the MMSI
In order for your ships location to be transmitted a GPS must be connected
to the MATRIX, refer to section 4.4 CONNECTION OF GPS WITH NMEA
OUTPUT
1. Lift the red spring loaded DISTRESS cover and
press the [
DISTRESS]
 key. The “DISTRESS” menu
will appear on the LCD.
2. Press and hold the [
DISTRESS]
 key. The radios
display will count down (3-2-1) and then transmit
the Distress call.
3. When the distress signal is sent, CH70 and “TX”
icon will appear on the LCD. After the message
has been sent, the radio will sound a Distress
Alarm.
4. The transceiver “shadow-watches” for a transmis-
sion between CH16 and CH70 until an acknowledgment signal is re-
ceived. “DISTRESS” and “WAITING” will appear on the LCD. 
						

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5. If an acknowledgement is received, select chan-
nel 16 and advise your distress situation.
6. If no acknowledgment is received, the distress call
is repeated in 4 minute intervals until an acknowl-
edgment is received.
7. When a DSC Distress acknowledgment is re-
ceived, a distress alarm sounds and channel 16
is automatically selected. The LCD shows the MMSI of the ship respond-
ing to your distress.
RECEIVED ACK:acknowledgment signal is received.
RECEIVED RLY:relay signal is received from another vessel or coast
station.
8. To cancel the DSC distress alarm signal from the speaker, press any
key.
Cancel a DSC Distress Call
If a DSC Distress call was sent by error the MATRIX allows you to send a
message to other vessels to cancel the Distress Call that was made in error.
Press the [
CALL/SET]
 key, turn the CHANNEL selector knob to select “CAN-
CEL.” Then, press the [
CALL/SET]
 key or turn off the radio.
7.5.2 Receiving a DSC Distress Call
1. A distress call is received.  An emergency alarm
sounds.
Then channel 16 is automatically selected.
2. Press any key to stop the alarm.
3. Turn the CHANNEL selector knob to change the
display to show the position of the vessel in dis-
tress.
4 If the position of the vessel distress data does not
include position, the LCD will show the display on
the left.
NOTE
You must continue monitoring channel 16 as a coast station may re-
quire assistance in the rescue attempt. 
						

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7.6  ALL SHIPS CALL
The All Ships Call function allows contact to be established with other vessel
stations without having their ID in the individual calling directory. Also, prior-
ity for the call can be designated as Urgency or Safety.
URGENCY Call: This type of call is used when a vessel may not truly be in
distress, but have a potential problem that may lead to a
distress situation. This call is the same as saying PAN PAN
PAN on channel 16.
SAFETY Call:Used to transmit boating safety information to other ves-
sels.  This message usually contains information about an
overdue boat, debris in the water.  Loss of a navigation aid
or an important meteorological message. This call is the
same as saying Securite” Securite” Securite’.
7.6.1  Transmitting an All Ships Call
1. Press the [
CALL/SET]
 key. The “DSC OPERA-
TION” menu will appear.
2. Turn the CHANNEL selector knob to select “ALL
SHIPS.”
3. Press the [
CALL/SET]
 key. (To cancel, turn the
CHANNEL selector knob to select “EXIT.”)
5. Turn the CHANNEL selector knob to select the
nature of call (“URGENCY” or “SAFETY”).
6. Press the [
CALL/SET]
 key to transmit the selected
type of all ships DSC call.
7. After the ALL SHIPS CALL is transmitted, the trans-
ceiver will switch to CH16.
8. Listen to the channel to make sure it is not busy,
then key the microphone and say PAN PAN PAN
or Securite” Securite” Securite depending on the
priority of the call. Then announce your call sign
and announce the channel you wish to switch to
for communications. 
						

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7.6.2 Receiving an All Ships Call
1. When an all ships call is received, an emergency
alarm sounds.
The radio will automatically change to channel 16.
2. Press any key to stop the alarm.
3. Turn the CHANNEL selector knob to see the MMSI
of the vessel transmitting the All Ships Call.
4. Monitor channel 16 or traffic channel until the UR-
GENCY voice communication is completed.
7.7  INDIVIDUAL CALL
This feature allows the MATRIX to contact another vessel with a DSC VHF
radio and automatically switch the receiving radio to a desired communica-
tions channel. This feature is similar to calling a vessel on CH16 and re-
questing to go to another channel (switching to the channel is private be-
tween the two stations).
7.7.1 Setting up the Individual / Position Call Directory
The MATRIX has a DSC directory that allows you to store a vessel or person
names and the MMSI number associated with vessels you wish to transmit
Individual calls, Position Requests and Position Send transmissions.
To transmit an Individual call you must program this directory with informa-
tion of the persons you wish to call, similar to a cellular phones telephone
directory.
1. Press and hold down the [
CALL/SET]
 key until
“RADIO SETUP” menu appears.
2. Turn the CHANNEL selector knob to select “DSC
SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “INDIV DIR”
with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key, then select “ADD” with
the CHANNEL selector knob.
5. Press the [
CALL/SET]
 key.
6. Turn the CHANNEL selector knob to scroll through
the first letter of the name of the vessel or person
you want to reference in the directory.
7. Press the [
CALL/SET]
 key to store the first letter
in the name and step to the next letter to the right. 
						

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8. Repeat step 6 and 7 until the name is complete.
The name can consist of up to eleven characters,
if you do not use all eleven characters press the
[
CALL/SET]
 key to move to the next space. This
method can also be used to enter a blank space in the name. To clear
the previous letter, press the [
H/L]
 key.
9. After the eleventh letter or space has been entered, press the [
CALL/
SET]
 key to advance to the MMSI (Maritime Mobile Service Identity Num-
ber) number entry.
10. Turn the CHANNEL selector knob to scroll through numbers, 0-9. To
enter the desired number and move one space to
the right press the [
CALL/SET]
 key. Repeat this
procedure until all nine space of the MMSI num-
ber are entered.
11. If a mistake was made entering in the name or the MMSI number repeat
pressing the [
CALL/SET]
 key until the wrong character is selected, then
move the channel knob to correct the entry.
12. To store the data entered, press and hold the [
CALL/SET]
 key.
13. To enter another individual address, repeat steps 4 through 13.
14. To exit this menu and return to radio operation mode press the [
16/9]
 key.
NOTE
Selecting “NEXT” or “EXIT” will automatically save the name and MMSI
number into memory.
7.7.2  Setting up Individual Reply
Allows setting up the radio to automatically (default setting) or manually
respond to a DSC Individual call requesting you to switch to a working chan-
nel for voice communications. When Manual is selected the MMSI of the
calling vessel is shown allowing you to see who is calling. This function is
similar to caller id on a cellular phone.
1. Press and hold down the [
CALL/SET]
 key until
“RADIO SETUP” menu appears.
2. Turn the CHANNEL selector knob to select “DSC
SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “INDIV
REPLY” with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key. 
						

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5. Turn the CHANNEL selector knob to select “AUTO”
or “MANUAL.”
6. Press the [
CALL/SET]
 key to store the selected
setting.
7. To exit this menu and return to radio operation
mode press the [
16/9]
 key.
7.7.3  Setting up Individual Call Ringer
When a Individual call is received the radio will produce a ringing tone for 3
minutes. This selection allows the Individual Call ringer time to be changed.
1. Press and hold down the [
CALL/SET]
 key until
“RADIO SETUP” menu appear.
2. Turn the CHANNEL selector knob to select “DSC
SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “INDIV
RING” with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key.
5. Turn the CHANNEL selector knob to select ring-
ing time of a Individual Call.
6. Press the [
CALL/SET]
 key to store the selected
setting.
7. To exit this menu and return to radio operation
mode press the [
16/9]
 key. 
						

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7.7.4  Transmitting an Individual Call
This feature allows the user to contact another vessel with a DSC radio. This
feature is similar to calling a vessel on CH16 and requesting to go to an-
other channel. Select the traffic channel for voice communication.
1. Press the [
CALL/SET]
 key. The “DSC OPERA-
TION” menu will appear.
2. Turn the CHANNEL selector knob to select “INDI-
VIDUAL.” (To cancel, select “EXIT” with the CHAN-
NEL selector knob or press the [
16/9]
 key.)
3. Press the [
CALL/SET]
 key. The transceiver will
beep, and the “Individual directory” will appear.
4. Turn the CHANNEL selector knob to select the
“Individual” you want to contact.
5. Press the [
CALL/SET]
 key to transmit the indi-
vidual DSC signal.
6. After INDIVIDUAL CALL is transmitted, the trans-
ceiver will wait 8 seconds for the acknowledgment.
If the reply signal is not received, the transceiver
will transmit again.
7. After the second INDIVIDUAL CALL is transmit-
ted, if the reply signal is not received, the dot ma-
trix area of the LCD will display “SEND” to prompt
the user to send the call again or exit the mode.
8. When an individual call acknowledgment is re-
ceived, the established channel is automatically
selected and a ringing tone sounds.
9. Press the [
CALL/SET]
 key to listen to the channel
to make sure it is not busy, then key the micro-
phone and call the other vessel you desire to com-
municate with. 
						

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7.7.5  Receiving an Individual Call
When receiving an individual call, an acknowledgment must be sent back to
the calling station. The MATRIX default setting is Automatic, but has a selec-
tion that allows you to manually send a reply before the radio will switch to the
requested calling channel. This selection is useful if you want to see who is
calling and requesting you to switch to a channel for communications, similar
to caller id on a cellular phone.
1. When an individual call is received, an individual
call ringing alarm sounds.
The radio automatically (automatic mode selected)
switches to the requested channel.
2. Press any key to stop the alarm.
3. Press the PTT on the mic and talk to the calling
ship.
4. Turn the CHANNEL selector knob to see the MMSI of the vessel calling.
7.7.6  Setting Up the Call Waiting Function
Allows the MATRIX to be setup to reply (ABLE) or set the radio so it trans-
mits a call that advises to the vessel the person is UNABLE to reply to the
call at this time. This function is similar to a answering machine. When set
up in UNABLE  and a individual call is received the Individual call from the
other vessel is logged in the CALL WAITING directory for you to review and
call back at a later time.
1. Press and hold down the [
CALL/SET]
 key until
“RADIO SETUP” menu appears.
2. Turn the CHANNEL selector knob to select “DSC
SETUP” menu.
3. Press the [
CALL/SET]
 key, then select “INDIV
ACK” with the CHANNEL selector knob.
4. Press the [
CALL/SET]
 key.
5. Turn the CHANNEL selector knob to select “ABLE”
or “UNABLE.”
6. Press the [
CALL/SET]
 key to store the selected
setting.
7. To exit this menu and return to radio operation
mode press the [
16/9]
 key.