Standard Horizon Marine Tranciever GX1255S Operating Instructions

							GX1255S3.4  OPTIONAL CMB16 FLUSH MOUNT INSTALLATION
1.Make a rectangular template for the flush mount measuring 2” H x
5-5/16” W.
2.Use the template to mark the location where the rectangular hole is to be
cut. Confirm the space behind the dash or panel is deep enough to ac-
commodate the transceiver (at least 6 inches deep).
There should be at least 1/2 inch between the transceiver’s heatsink and
any wiring, cables or structures.
3.Cut out the rectangular hole and insert the transceiver.
4.Fasten the brackets to the sides of the transceiver with the lock washer
nut combination, so that the mounting screw base faces the mounting
surface (see Figure 2).
5.Turn the adjusting screw to adjust the tension so that the transceiver is
tight against the mounting surface.
Figure 2. CMB16 Flush Mount InstllationBracket
Adjusting Screw
Lock-washer nut combinationPage 9 
						

							GX1255SPage 104  CONTROLS AND INDICATORS
NOTE
This section defines each control of the transceiver. See Figure 3 for
location of controls. For detailed operating instructions refer to chapter
5 of this manual.
4.1  CONTROLS AND CONNECTIONSPOWER SWITCH/VOLUME CONTROL
Turns the transceiver on and off as well as adjusts the audio volume.
Turn this control clockwise to turn the radio on and to increase the vol-
ume.
Turn fully counterclockwise to turn the radio off.
Secondary Use
When the transceiver is turned on while the SCAN and WX keys are
held down, the internal microprocessor is reset. This clears the memory
and all user-programmed settings, such as scan memory. This condition
is known as the default condition, the same as when shipped from the
factory. For a list of these defaults, see the section on Resetting the
Transceiver’s Microprocessor.
NOTE
Resetting the microprocessor will not erase DSC MMSI and Direc-
tory Call information.SQUELCH CONTROL (SQL)
Sets the point at which random noise on the channel does not activate
the audio circuits but a received signal does. This point is called the
squelch threshold. Further adjustment of the squelch control will degrade
reception of wanted transmissions.KEYPAD
16/9 Key
Immediately recalls channel 16 from any channel location. Holding down
this key recalls channel 9. Pressing the 16/9 key again reverts to the
previous selected working channel.
Secondary use
Please see secondary use for the WX key. 
						

							GX1255SFigure 3. Controls and ConnectorsPage 11 
						

							GX1255SPage 12WX Key
Immediately recalls the previously selected NOAA weather channel from
any channel location.
Secondary use
1.Holding down the 16/9 key while pressing the WX key changes the
mode from USA to International or Canadian.
2.Holding down the WX and SCAN key while turning the power on
resets the microprocessor and erases scan channels from memory.
This clears the memory and establishes the factory-set defaults. For
a list of these defaults, see the section on Resetting the Transceiver’s
Microprocessor.
DW Key
Watches for a transmission on CH16 and another selected channel until
either signal is received. (Dual watch)
NOTE: When the DSC SCANNING feature is enabled(see section 7.10
DSC SCANNING), the radio watches for a transmission on CH16, an-
other selected channel, and CH70 until either signal is received (Triple
watch).
H/L Key
Toggles between high and low power. When the H/L key is pressed while
the transceiver is on channel 13 or 67, the power will temporarily switch
from LO to HI power until the PTT is released. The H/L key does not
function on transmit inhibited and low power only channels.
Secondary use
Press and hold the H/L key to display the Position Data on the LCD,
when connected to the GPS receiver.
SCAN Key
1.Starts and stops scanning of programmed channels.
2.If held while the UP or DOWN key on the microphone are pressed or
UP or DOWN key on radio are pressed, the radio will show the chan-
nels programmed in scan memory. This function will not work if the
unit is scanning.
NOTE: The priority channel is channel 16 only. 
						

							GX1255SCALL/SET Key
The CALL/SET key functions as the enter key.
Secondary use
Press the CALL/SET key to access the DSC OPERATION menu. The
INDIVIDUAL and ALL SHIPS CALLS functions can be accessed from
the DSC OPERATION menu.
Press and hold the CALL/SET key to access the RADIO or DSC setup
menu. The following functions can be accessed in the menu.
DISTRESS Key
Used to send a DSC Distress Call. To send the distress call see section
6.2 (Sending a Distress Call).
UP and DOWN Keys
The UP and DOWN keys are used to select a desired channel and to
select items in the DSC OPERATION and SETUP menus. The UP or
DOWN key on the microphone can also be used to select channels.RADIO SETUP MENU
DSC SETUP MENU
Page 13 
						

							GX1255SPage 14ACCESSORY CONNECTION CABLE
Connects the radio to a GPS, and an external speaker.DC INPUT CABLE
Connects the radio to a DC power supply of 13.8VANTENNA JACK
Connects an antenna to the transceiver. Use a marine VHF antenna with
an impedance of 50 ohms.PTT (Push-To-Talk) SWITCH
Keys the transmitter.MICROPHONE
Transmits the voice message with reduction of background noise.UP(p) and DOWN(q) KEYS
The UP(p) and DOWN(q) on the microphone function the same as the
UP and DOWN key on the front panel of the transceiver.16/9 Key
Pressing the 16/9 key Immediately recalls channel 16 from any location.
Press and hold the 16/9 key to recall channel 9. Pressing the 16/9 key
again revert the radio to the previous select channel. 
						

							GX1255S5  BASIC OPERATION
5.1  RECEPTION
1.After the transceiver has been installed, ensure that the power supply
and antenna are properly connected.
2.Turn the VOL/PWR knob clockwise to turn on the radio.
3.Turn the SQL knob fully counterclockwise. This state is known as “squelch
off”.
4.Turn up the VOL/PWR knob until noise or audio from the speaker is at a
comfortable level.
5.Turn the SQL knob clockwise until the random noise disappears. This
state is known as the “squelch threshold.”
6.Press the UP or DOWN key to select the desired channel. Refer to the
channel chart on page 48 for available channels.
7.When a message is received, adjust the volume to the desired listening
level. The “BUSY” indicator in the LCD is displayed indicating that the
channel is being used.
5.2  TRANSMISSION
1.Perform steps 1 through 6 of RECEPTION.
2.Before transmitting, monitor the channel to ensure it is clear. THIS IS AN
FCC REQUIREMENT!
3.Press the PTT (push-to-talk) switch. The TX indicator on the LCD is dis-
played.
4.Speak slowly and clearly into the microphone.
5.When the transmission is finished, release the PTT switch.
NOTE
This is a noise-canceling microphone. The oval slot on the bottom of
microphone should be positioned within 1 inch (2.5 cm) from the
mouth for optimum performance.
6.Refer to page 38 for operating practices.
5.3  TRANSMIT TIME - OUT TIMER (TOT)
When the PTT switch on the microphone is held down, transmit time is limited
to 5 minutes. This limits unintentional transmissions due to a stuck micro-
phone. About 10 seconds before automatic transmitter shutdown, a warning
beep will be heard from the speaker(s). The transceiver will automatically go
to receive mode, even if the PTT switch is continually held down. Before trans-
mitting again, the PTT switch must first be released and then pressed again.Page 15 
						

							GX1255SPage 16 5.4  SIMPLEX/DUPLEX CHANNEL USE
Refer to the VHF MARINE CHANNEL CHART (page 49) for instructions on
use of simplex and duplex channels.
NOTE
All channels are factory-programmed in accordance with FCC (USA),
Industry Canada (Canada), and International regulations. Mode of op-
eration cannot be altered from simplex to duplex or vice-versa.
5.5  USA, CANADA, AND INTERNATIONAL MODE
1.To change the modes, hold the 16/9 key and press the WX key. The
mode changes from USA to International to Canadian with each press of
the WX key.
2.“U” will be displayed on the LCD for USA mode, “I” will be displayed for
International mode, and “C” will be displayed for Canadian mode.
3.Refer to the VHF MARINE CHANNEL CHART (page 49) for allocated
channels in each mode.
5.6  NOAA WEATHER CHANNELS
1.To receive a NOAA weather channel, press the WX key from any chan-
nel. The transceiver will go to the last selected weather channel.
2.Press the UP or DOWN key on the microphone or on front panel to
select a different NOAA weather channel.
3.To exit from the NOAA weather channels, press the WX key. The trans-
ceiver returns to the channel it was on prior to a weather channel. 
						

							GX1255S5.7  NOAA WEATHER ALERT
In the event of extreme weather disturbances, such as storms and hurri-
canes, the NOAA (National Oceanic and Atmospheric Administration) sends
a weather alert accompanied by a 1050 Hz tone and subsequent weather
report on one of the NOAA weather channels. When the Weater Aleart fea-
ture is enabled (see section 7.4 WEATER ALERT), the transceiver is ca-
pable of receiving this alert if the following is performed:
1.Program NOAA weather channels into the transceiver’s memory for scan-
ning. Follow the same procedure as for regular channels under Section
5.8.
2.Press the SCAN key once to start memory scanning or hold down the
SCAN key during memory scanning to start priority scanning.
3.The programmed NOAA weather channels will be scanned along with
the regular-programmed channels. However, scanning will not stop on a
normal weather broadcast unless a NOAA alert is received.
4.When an alert is received on a NOAA weather channel, scanning will
stop and the transceiver will emit a loud beep to alert the user of a NOAA
broadcast.
5.Press the WX key to stop the alert tone and receive the weather report.
NOTE
If the WX key is not pressed the alert tone will be emitted for 5 minutes
and then the weather report will be received.
NOTE
The Weather Aleart feature is also engaged while the transceiver is
received on the one of the NOAA weather channel.Page 17 
						

							GX1255SPage 185.8  MEMORY SCANNING (M-SCAN)
NOTE
•During scanning, the dot matrix area of the LCD will show M-SCAN or
P-SCAN depending on the scan mode selected.
•If GPS position is displayed this icon will be hidden.
1.Adjust the SQL knob until background noise disappears.
2.Select a desired channel to be scanned using the UP or DOWN key.
Press and hold the SCAN key, MEM will appear on the
LCD which indicates the channel has been programmed
into the transceivers memory.
3.Repeat step 2 for all the desired channels to be scanned.
4.To DELETE a channel from the transceiver’s memory, press and hold
the SCAN key, MEM will disappear in the LCD.
5.To start scanning, press the SCAN key. Scanning will
proceed from the lowest to the highest programmed
channel number and will stop on a channel when a trans-
mission is received.
6.The channel number will blink during reception.
7.To stop scanning, press the SCAN, 16/9, WX, or PTT key.
5.9  PRIORITY SCANNING (P-SCAN)
1.The priority channel is set to channel 16.
2.For priority scanning during M-SCAN, press and hold
the SCAN key, until P-SCAN appears in the LCD. Scan-
ning will proceed between the memorized channels and
the priority channel. The priority channel will be scanned
after each programmed channel.ø: When DSC Scanning method is enabled. Default is DSC scan is ON.
3.The scanning will be performed while receiving the MEM
CH (memorized channel).
4.To stop scanning, press the SCAN, 16/9, WX, or PTT
key.
NOTE
Triple watch (T/W) means the radio is watching CH70 for DSC Calls.
Dual watch (D/W) means the radio is not watching CH70 for DSC Calls.MEM CH.CH. 16ø
CH. 70MEM CH.CH. 16ø
CH. 70