Standard Horizon Marine Tranciever GX1255S Operating Instructions

							GX1255S5.10  POSITION INDICATION
The transceiver has the ability to display the vessel’s position (LAT/LON) for
Confirmation of the data, if connected to a GPS receiver.
1.Press and hold the H/L key, displays
“LAT” and “LON” information alternately
every two seconds.
If the GPS receiver receives no signal,
the display will be as shown in the illus-
tration.
2.To hide the position information, press and hold the H/L
key again.
5.11  TIME INDICATION
When press and hold the 16/9 and H/L keys while turn the
transceiver on, the transceiver will display the TIME on the
upper side, if connected to a GPS receiver.
NOTE
The TIME OFFSET should be set to local time in the DSC/RADIO setup
mode when the radio is connected the GPS navigation receiver. To ad-
just TIME OFFSET to your local time, refer to section 7.6 TIME OFF-
SET.
5.12  RESETTING THE TRANSCEIVER’S MICROPROCESSOR
Resetting the microprocessor restores the initial, factory supplied conditions
in the transceiver. These are called the default conditions.
To reset the microprocessor, first turn the transceiver off. Then while press-
ing the WX and SCAN keys, turn the transceiver on. The default conditions
are:
•No channels in SCAN memory.
•Channel 16 will be selected when the transceiver is turned on.
•WX channel 01 will be recalled when the WX key is pressed.
•Key beep will be on.
NOTE
Resetting the microprocessor will not erase DSC MMSI and Directory
information.(Latitude)(Longitude)
(No GPS Signal)Page 19 
						

							GX1255SPage 206  DIGITAL SELECTIVE CALLING
6.1  GENERAL6.1.1  Digital Selective Calling (
DSC)
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
had 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 will allow 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 mari-
ners to initiate or receive distress, urgency, safety routine, POS Request,
POS Send and Group calls to or from another vessel equipped with a DSC
transceiver.6.1.2  Maritime Mobile Service Identity (MMSI)
What is an MMSI?
An MMSI is a nine digit number used on Marine Transceiver capable of
using Digital Selective Calling (DSC). This number is used like a telephone
number to selectively call other vessels. Refer to section 7.9 (USER MMSI
INPUT).
How can I obtain a MMSI assignment?
Contact your dealer, or Standard Horizon for details.
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. 
						

							GX1255S6.2  SENDING A DISTRESS CALL
The distress call automatically includes the vessel’s DSC MMSI and Lat/
Lon position. Refer to section 7.9 (USER MMSI INPUT). The vessel’s posi-
tion can be sent only if the transceiver is properly connected to an operating
GPS receiver.
1.Lift the red spring loaded DISTRESS cover and press
the DISTRESS key. The “DISTRESS” icon will appear
on the LCD.
2.Press and hold the DISTRESS key. The LCD will count
down (3, 2, 1) following this the QUEST will transmit the Distress Call.
3.When the distress signal is sent, “TX” icon will appear
on the LCD. After the message has been sent, the Dis-
tress Alarm will sound.
4.The transceiver “shadow-watches” for a transmission
between CH16 and CH70 until an acknowledgment sig-
nal is received. “RECEIVED ACK” will scroll on the LCD.
5.If no acknowledgment is received, the distress call is
repeated in 3.5 to 4.5 minute intervals until an acknowl-
edgment is received.
6.To cancel a Distress Call
1)Press the 16/9 key
2)Press the WX key
3)Turn off the radio
4)Press the DISTRESS key, then press the UP or
DOWN key until “CANCEL” is shown on the LCD.
Press the CALL/SET key.
7.When a distress acknowledgment is received, a distress
alarm sounds and channel 16 is automatically selected.
8.To cancel the alarm, press any key.
NOTE
When a GPS receiver with NMEA output is connected, the vessel’s po-
sition is automatically transmitted with the distress call.Page 21 
						

							GX1255SPage 22 6.3  SENDING AN INDIVIDUAL CALL
This feature allows the user to contact another user vessel DSC and to
automatically switch the receiving DSC radio to a desired working channel.
This feature is similar to calling a vessel on CH16 and requesting to go to a
another channel. To send an individual call, see section 7.5 INDIVIDUAL
DIRECTORY SETUP and 7.11 USER MMSI INPUT. The individual call func-
tion allows you to transmit a DSC signal to a specific party only, prompting
communication on a voice channel.
1.Select the traffic channel for voice communication.
2.Press the CALL/SET key. The “INDIVIDUAL” icon will
appear on the LCD.
3.Press the CALL/SET key again. The individual address
will appear.
4.Press the UP or DOWN key to select the individual you
want to contact.
5.To cancel, if needed, press the UP or DOWN key until
the “EXIT” icon appear. Then press the CALL/SET key.
This procedure can be also canceled by pressing the WX or 16/9 key.
6.Press the CALL/SET key to transmit the individual DSC signal.
7.After an INDIVIDUAL CALL is transmitted, the transceiver will wait 8 sec-
onds for the acknowledgment. If the reply signal is not received, the
transceiver will transmit again.
8.After the second INDIVIDUAL CALL is transmitted, if the
reply signal is not received, “NO REPLY” icon will ap-
pear on the LCD to prompt the user to send the call
again or exit the mode.
9.When an individual call acknowledgment “able to comply” is received,
the established channel is automatically selected and an alarm sounds.
10.When an individual call acknowledgment with “unable to comply” is re-
ceived, the established channel is automatically selected. 
						

							GX1255S6.4  SENDING AN 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, priority for the call can be designated as Urgency, Safety or Routine.
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 (PAN, PAN,Call Type).
SAFETY Call:Used to transmit boating safety information to other ves-
sels (Security Call Type).
This message usually contains information about an overdue boat, debris in
the water. Loss of a navigation aid or an important meteorological message.
1.Select the traffic channel (for voice communication).
2.Press the CALL/SET key. The “INDIVIDUAL” icon will
appear on the LCD.
3.Press the DOWN key to select the “ALL SHIPS.”
4.Press the CALL/SET key again.
5.Press the DOWN key to select the nature of call (“UR-
GENCY,” “SAFETY” or “ROUTINE”).
6.Press the CALL/SET key to transmit the selected type
of ALL SHIPS DSC call. When “ROUTINE” is selected,
the signal is transmitted then the transceiver will wait on
the channel selected in step 1.
7.After the ALL SHIPS CALL is transmitted, the transceiver
will wait on CH16 except when a ROUTINE. Call has
been transmited.Page 23 
						

							GX1255SPage 24 6.5  RECEIVING DSC CALLS
Several types of DSC transmissions can be received. The required action
depends on the particular DSC type as outlined in the following examples.
NOTE
If the radio is receiving on a working channel or transmitting on a work-
ing channel, DSC calls will not be received.6.5.1  Receiving a distress call
1.A distress call is received. “RECEIVED DISTRESS” will
appear on the LCD, and an emergency alarm will be
heard.
Channel 16 is automatically selected.
2.Press any key to stop the alarm.
3.Press the UP or DOWN key to select the receiving dis-
tress data:
•MMSI or Station Name•TIME (UTC)
•Latitude•Longitude
NOTE
•If the received distress data does not include the position data, “NO
POSITION DATA” will scroll on the LCD.
•You must continue monitoring channel 16 as a coast station may re-
quire assistance in any rescue attempt.6.5.2  Receiving a distress relay call
1.A distress relay call is received. “RECEIVED RLY” will
appear on the LCD, and an emergency alarm will be
heard.
Channel 16 is automatically selected.
2.Press any key to stop the alarm.
3.Press the DOWN key to appear the receiving distress
data (MMSI or Station Name).
NOTE
You must continue monitoring channel 16 as a coast station may re-
quire assistance in any rescue attempt. 
						

							GX1255S6.5.3  Receiving an all ships call
1.An all ships call is received. “RECEIVED ALL SHIPS”
will appear on the LCD, and an emergency alarm will be
heard.
Channel 16 is automatically selected.
2.Press any key to stop the alarm.
3.Press the UP or DOWN key to select the receiving dis-
tress data:
•MMSI or Station Name
4.Monitor channel 16 or traffic channel until the communi-
cation is completed.6.5.4  Receiving a geographical area call
1.A geographical call is received. “RECEIVED GEO-
GRAPHIC” will appear on the LCD, and an emergency
alarm will be heard (different from DISTRESS). Then
the requested channel from the other ship is automati-
cally selected.
2.Press any key to stop the alarm.
3.Press the UP or DOWN key to select the receiving dis-
tress data:
•MMSI or Station Name
4.Monitor the traffic channel for an announcement from
the calling ship.
NOTE
This feature is only available when a GPS receiver is connected.Page 25 
						

							GX1255SPage 266.5.5  Receiving an individual call
When receiving an individual call, an acknowledgment must be sent back to
the calling station. Please refer to a selection in the 7.DSC/RADIO SETUP
MODE that allows the acknowledgment to be transmitted manually or auto-
matically. Refer to 7.8 INDIVIDUAL REPLY and 7.9 INDIVIDUAL ACK sec-
tions for details.
Automatic Reply:
1.An individual call is received. “RECEIVED INDIVIDUAL”
will appear on the LCD, and an individual call alarm
sounds. Then the radio automatically switches to the
requested channel.
2.Press any key to stop the alarm, then acknowledgment is transmitted
automatically.
4.Press the PTT on the microphone and talk to the calling ship.
Manual Reply:
1.An individual call is received. “RECEIVED INDIVIDUAL”
will appear on the LCD, and an individual call alarm
sounds. Then the radio automatically switches to the
requested channel.
2.Press any key to stop the alarm.
3.Select type of reply function “ABLE” or “UNABLE” by
using the UP or DOWN key. In the Automatic mode,
the acknowledgment is transmitted automatically.
4.Press the PTT on the microphone and talk to the calling ship. 
						

							GX1255S6.5.6  Receiving a position request
When position request call is received from another vessel, a calling alarm
will sound. Please refer to section 7.DSC/RADIO SETUP MODE that allows
the position request to be transmitted manually or automatically. Refer to
7.11  POSITION REQUEST REPLY section for details.
Automatic Reply:
1.When a position request call is received, “RECEIVED
POS REQUEST” will appear on the LCD, and a calling
alarm will sound.
2.Press the any key to disable the calling alarm, then the
requested position coordinates will be transmitted.
5.To exit from position request display, press any key.
Manual Reply:
1.When a position request call is received, “RECEIVED
POS REQUEST” will appear on the LCD, and a calling
alarm will sound.
2.Press the any key to disable the calling alarm.
3.Select type of reply function ABLE or EXIT by using the
UP or DOWN key.
4.When ABLE is selected, press the CALL/SET key. And
the requested position coordinates will be transmitted.
5.To exit from position request display, press any key.Page 27 
						

							GX1255SPage 287.  DSC / RADIO SETUP MODE
7.1  LAMP ADJUSTING
1.Press and hold down the CALL/SET key until “RADIO
SETUP” appears.
2.Press the CALL/SET key to select “LAMP.”
3.Press the CALL/SET key to enable adjusting this item
(The number in the display will flash).
4.Press the UP or DOWN key to select the desired level.
3:High
2:Mid
1:Low
0:OFF
5.Press the CALL/SET key to store the selected level.
6.Press the DOWN key to select “EXIT,” then press the
CALL/SET key.
7.Press the DOWN key to select “EXIT,” then press the
CALL/SET key to return to the normal operation.
7.2  LCD CONTRAST ADJUSTING
1.Press and hold down the CALL/SET key until “RADIO
SETUP” appears.
2.Press the CALL/SET key, then press the UP or DOWN
key to select “CONTRAST.”
3.Press the CALL/SET key to enable adjusting this item
(The number in the display will flash).
4.Press the UP or DOWN key to adjust the contrast. Avail-
able values are 7 “dark” through 0 “light.”
5.Press the CALL/SET key to store the selected level.
6.Press the DOWN key to select “EXIT,” then press the
CALL/SET key.
7.Press the DOWN key to select “EXIT,” then press the
CALL/SET key to return to the normal operation.