Filter
Top Products
1-2
Garmin GNC 255A/255B Pilot’s Guide
190-01182-01 Rev. A
1.2 Pilot Controls
The GNC 255 controls have been designed to simplify operation of the
system and minimize workload and the time required to access sophisticated
functionality. Controls are comprised of dual concentric knobs for frequency
tuning, Com volume/squelch knob, Nav volume/ID knob, and bezel keys.
1.2.1 Power/Com Volume/Squelch Knob
The Power/Com Volume/Squelch knob located in the top left
corner of the bezel controls audio volume for the Com radio.
Rotating the knob clockwise past the detent turns power on
and counter-clockwise turns power off. When the Com radio is
active, press the Power/Com Volume/Squelch knob to toggle
automatic squelch control On/Off for the Com radio.
Squelch, TX, or RX
Annunciator
Com Volume Bar Graph
Active Frequency
Annunciator
Com Mode
Annunciator
Active Nav
Frequency
Standby Frequency
Annunciator
Figure 1-2 Com Volume and Squelch Display Description
The Com radio features an automatic squelch to reject many localized noise
sources. You may override the squelch function by pressing the
Power/Com
Volume/Squelch
knob. This facilitates listening to a distant station or setting
the desired volume level.
To override the automatic squelch, press the
Power/Com Volume/Squelch
knob momentarily. Press the
Power/Com Volume/Squelch
knob again to
return to automatic squelch operation. A “SQ” indication appears to the left of
the active Com frequency window in the upper left corner of the display when
automatic squelch is overridden.
1.2.2 Nav Volume/ID Knob
The Nav Volume/ID knob located in the bottom left corner
of the bezel controls audio volume for the Nav radio. Press the
Nav Volume/ID knob and the Morse code tones will be heard.
When Morse code tone is active, “ID” will appear to the left of
the Nav active frequency.