Garmin GNC 255A Pilot's Guide

1-2 Garmin GNC 255A/255B Pilot’s Guide 190-01182-01 Rev. E
Getting Started
1.2 Pilot Controls
The GNC 255 controls are designed to simplify systems operation, minimize
workload, and reduce time required to access functionality. Controls are comprised
of dual concentric knobs for frequency tuning, COM volume/squelch knob, NAV
volume/ID knob, and bezel keys.
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. To power on, turn the knob clockwise
past detent. Turn the knob counterclockwise to 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.
COM Volume and Squelch Display
The COM radio has 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. When the automatic squelch is overridden, an “SQ”
indicator appears in the upper left corner of the display, left of the active COM
frequency window.
Squelch, TX, or RX
Annunciator
Active Frequency
Annunciator
COM Volume Bar Graph
Standby Frequency
Annunciator
COM Mode
Annunciator
Active NAV
Frequency

Garmin GNC 255A Specifications

General

Brand	Garmin
Model	GNC 255A
Category	Transceiver
Language	English