Standard Horizon GX2400GPS Owner's Manual page 127

DIAL/ENT knob
While the normal screen is displayed, rotate the DIAL/ENT knob to select
your desired channel. While the MENU screen is displayed, rotate the knob
to select the desired menu item.
Secondary use
Press this knob to enter a selection in the MENU.
SQL key (Squelch control)
Press this key to activate the squelch adjusting mode. Press the CH▲ or
CH▼ key to adjust the squelch threshold level.
PTT (Push-To-Talk) switch
Push this switch to enable the transmitter.
CLEAR/
Press this key to cancel a menu selection. Press and hold this key to activate the
key lock function. Press and hold this key again to deactivate the key lock function.
Microphone
The internal microphone transmits your voice while reducing background
noise using Clear Voice Noise Reduction Technology.
NOTE: Position the microphone about 1.5 cm away from your mouth and speak in a normal voice.
◄ & ► keys
When the soft keys are displayed, press these keys to switch the function
of the soft keys.
Secondary use
While the MENU screen is displayed, press the keys to slide the on-screen
menu to the right/left side.
MENU key
Press to access the MENU.
Press and hold this key to access the SETUP MENU.
CH▼ & CH▲ keys
These keys are used to change the operating channel.
Press the key momentarily, the channel increases or decreases one step.
Hold the key and the channel increases or decreases continuously.
Secondary use
 While the MENU screen is displayed, press the key to slide the on-screen
menu upward/downward.
 When in the PA or Fog mode, press the key to change the channel.
Display
Full dot matrix display, 222 by 162 pixels.
key
MMSI and ATIS Display Area (Fixed)
Channel and Operation status
Display area
125