Garmin 255A manual Pilot Controls, Power/Com Volume/Squelch Knob, Nav Volume/ID Knob

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1.2Pilot 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.

1.2.1Power/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.

Com Mode

Annunciator

Squelch, TX, or RX
Annunciator
Annunciator
Active Frequency									Active Nav
Active Frequency									Active Nav
Annunciator									Frequency
Annunciator									Frequency

			Com Volume Bar		Graph	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.

1.2.2Nav 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.

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Garmin GNC 255A/255B Pilot’s Guide

190-01182-01 Rev. A

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Contents GNC 255A/255B November Limited Warranty 190-01182-01 Rev. a Iii Operation Product Registration and Support US Toll Free Canada Toll FreeRecord of Revisions Contents 2.3 2.12.2 Index Index-1 This page intentionally left blank Getting Started Product DescriptionPilot Controls Power/Com Volume/Squelch KnobNav Volume/ID Knob 5 C/N Com/Nav Key Tuning LARGE/SMALL Concentric Cursor KnobsFLIP/FLOP Key OBS KeyMON Monitor Key USB PortFunc Function Key Selecting a Com Frequency Power OnCom Radio After selecting the desired characters, press ENT Monitoring the Standby Com ChannelSaving a Com Channel Description After making a selection, press ENTCom Database Look-Up Frequency Database Reverse Look-UpRemote Frequency Selection Control Emergency ChannelStuck Mic Saving a Nav Channel Nav RadioSelecting a Nav Frequency Listening to the Nav Audio Channel 01-36OBS Mode 14 CDI DisplayDistance/Speed/Time DST Display 15 DST Data DisplayThis page intentionally left blank Functions Functions DescriptionTurn the Small knob to select an Entry Com FrequenciesRecent Com Frequencies Com User Frequencies Press the CLR key to delete this User frequencyEditing a Com User Frequency Frequencies. Press ENTCom Database Frequencies Com Database FrequenciesCom Nearest Airports APT Nearest APT function. Then, press ENTCom Nearest Area Control Center ACC Frequencies Turn Small Knob To Scroll Through Available FrequenciesCom Nearest Flight Service Station FSS Frequencies 13 Com Nearest FSS FrequenciesCom Nearest Weather WX Frequencies 14 Com Nearest Weather FrequenciesNav Frequencies Recent Nav FrequenciesNav User Frequencies Press the ENT key to delete the displayed frequencyEditing a Nav User Frequency Nav Database Frequencies 21 Nav Database FrequenciesWhen duplicate identifiers are found, press ENT Nav Nearest VORTurn the Small knob to display the available VORs ICS ConfigurationAdjust Intercom Functions displayAux Audio Turn the Small knob to turn the Aux Audio On or OffIntercom On/Off function. Then, press the ENT key Intercom On/OffSpeaker On/Off Speaker On/Off function. Then, press ENTSystem Configuration Com SpacingDisplay Brightness 34 Set Display BrightnessDisplay Contrast function. Then, press the ENT key Display ContrastDatabase Info Database Version function. Then, press the ENT keyLoad Database Load Database function. Then, press the ENT keySoftware Version function. Then, press the ENT key Software VersionSerial Number Press the Func key to return to the main menuTo select a starting timer value TimersSetting Up the Count Down Timer Pressing CLR and then ENT will reset the displayed Timer Setting Up the Count Up TimerViewing Timers in the Com Display Pressing ENT twice will stop the displayed Timer48 Count Down Timer Value Now Counting Up This page intentionally left blank Troubleshooting AppendixIf in Lock Out mode It can be enabledOr disabled via a Remote mounted Calibration error Recalibrate resolverUpdating the Frequency Database Messages Verify glideslope deviation Power has been Re-apply power to the unitSwitch has been Property withRemote com All installationsInstallations Been in pressedProperty with System Nav radio is Contact dealer for serviceNot communicating This page intentionally left blank Index Remote frequency control 2-5 Reverse look-up 2-4 Revisions