Garmin GTR 225, GNC 255 Supplement

GTR 225/GNC 255 SERIES SOFTWARE VERSION 2.10 UPGRADE SUPPLEMENT

The Pilot’s Guides have been revised for Software Version 2.10. This supplement provides
information regarding new features of Software Version 2.10 for the GTR 225/GNC 255
Series units.

• GTR 225/225A/225B Pilot’s Guide
(Garmin P/N 190-01182-00) Rev B

• GNC 255A/255B Pilot’s Guide
(Garmin P/N 190-01182-01) Rev B

NOTE: The combination of the following documents is equivalent to the
Pilot’s Guide revisions listed above.

• GTR 225/GNC 255 Series Software Version 2.10 Upgrade Supplement

and either

• GTR 225/225A/225B Pilot’s Guide
(Garmin P/N 190-01182-00) Rev A

or

• GNC 255A/255B Pilot’s Guide
(Garmin P/N 190-01182-01) Rev A

Current documents are available at https://fly.garmin.com/fly-garmin/support/ for free
download. Printed copies may be purchased by contacting Garmin Customer Support.

NOTE: Depending on which version of software is installed and how it is
configured, the actual features and screen images may differ from what is
shown. Refer to the GTR 225/225A/225B Pilot’s Guide, P/N 190-01182-00,
or GNC 255A/255B Pilot’s Guide, P/N 190-01182-01, for more information
regarding feature availability for specific software versions.

NOTE: All sections are applicable to Rev A Pilot’s Guides. Sections
designated “SW Version 2.10” are applicable to Rev B Pilot’s Guides.

© 2012-2015 Garmin Ltd. or its subsidiaries. All rights reserved.

This manual reflects the operation of System Software version 2.10, or later. Some differences in operation
may be observed when comparing the information in this manual to later software versions.

Garmin International, Inc., 1200 East 151st Street, Olathe, KS 66062, U.S.A.
Tel: [phone] Fax: [phone]

Garmin AT, Inc., 2345 Turner Road SE, Salem, OR 97302, U.S.A.
Tel: [phone] Fax [phone]

Garmin (Europe) Ltd., Liberty House, Bulls Copse Road, Hounsdown Business Park, Southampton,
SO40 9LR, U.K.
Tel. [phone] Fax [phone]

Garmin Singapore Pte. Ltd., 46 East Coast Road, #05-06 Eastgate, Singapore 428766
Tel : [phone] Fax : [phone]

At Garmin, we value your opinion. For comments about this guide, please e-mail:
[e-mail]

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https://fly.garmin.com/fly-garmin

Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted,
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permission of Garmin. Garmin hereby grants permission to download a single copy of this manual and of
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of this copyright notice and provided further that any unauthorized commercial distribution of this manual
or any revision hereto is strictly prohibited.

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Garmin® is a registered trademarks of Garmin Ltd. or its subsidiaries. These trademarks may not be used
without the express permission of Garmin.

March 2015

Printed in the U.S.A.

Table of Contents

1 Getting Started ...................................................................... 1

1.3 USB Port .................................................................................................. 1

2 Basic Operation ...................................................................... 1

2.2.1 Selecting a COM Frequ

2.2.5 (2.2.7) Frequency Database Reverse Look-Up .................................. 2

2.4 OBS Mode ................................................................................................ 2

2.5 Distance/Speed/Time (DST) Display ............................................................ 3

3 Functions ................................................................................ 4

3.1 Functions Description ................................................................................ 4

3.2 COM Frequencies ...................................................................................... 5

3.2.3 COM Database Frequencies ............................................................. 5

3.4 (3.3) ICS Configuration .............................................................................. 5

3.4.1 (3.3.1) Adjust Intercom .................................................................... 6

3.4.2 (3.3.2) AUX Audio ........................................................................... 7

3.4.3 (3.3.3) Intercom On/Off ................................................................... 8

3.4.4 (3.3.4) Speaker On/Off .................................................................... 8

3.5 (3.4) Systems Configuration ...................................................................... 9

3.5.2 (3.4.2) COM Sidetone Section (Software v2.10 or later) ................... 9

3.5.7 (3.4.7) Serial Number .................................................................... 10

ency ............................................................. 1

4 Appendix .............................................................................. 10

4.2 Updating the Frequency Database ........................................................... 10

4.2.1 Downloading the Frequency Database ........................................... 10

4.3 Messages ................................................................................................ 11

GTR 225/GNC 255 Series Software Version 2.10 Upgrade Supplement 190-01182-10 Rev. A

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1 GETTING STARTED

1.3 USB Port

GNC 255A/255B - Page 1-4, GTR 225/225A/225B - Page 1-4
Added the following note.

NOTE: For updating the databases, Garmin recommends the use of a USB

2.0 compatible flash drive. Th

e flash drive must be formatted as FAT32.

2 BASIC OPERATION

2.2.1 Selecting a COM Frequ

GNC 255A/255B – Page 2-1, GTR225/225A/225B – Page 2-1
Added information about behavior when connected to a position source.

New frequencies are first selected as a standby frequency and then toggled to
the active side with the
display, use the outer and inner knobs on the right side of the unit to select the
desired frequency.

Identifier and Type

1. Press COM (C/N), if necessary, to reach the COM radio function. The
COM annunciator on the top line of the display will show.

2. Turn the outer knob to change the values in one MHz increments. The
MHz selection range is between 118 and 136 in one MHz steps.

3. Turn the inner knob to change the values in 25 kHz or 8.33 kHz
increments. The kHz selection range is between 000 and 975 kHz in
25 kHz steps or 000 and 990 kHz in 8.33 kHz steps.

FLIP/FLOP

COM Frequency Selection

ency

key. While viewing the standby frequency

Asterisk Indicates Multiple Types
Exist For The Selected Frequency

4. Turn the outer and inner knobs clockwise to increase and counterclockwise
to decrease the frequency values. Standby frequency selection is not
inhibited during transmit.

GTR 225/GNC 255 Series Software Version 2.10 Upgrade Supplement 190-01182-10 Rev. A

1

5. When connected to a position source, the nearest station identifier will
be shown for the selected frequency. Frequencies with multiple types will
have an asterisk next to the identifier.

6. Press and release the FLIP/FLOP key to toggle the standby frequency to
the active frequency.

2.2.5 (2.2.7) Frequency Database Reverse Look-Up

GNC 255A/255B – Page 2-4, GTR 225/225A/225B – Page 2-5
Added information about behavior when connected to a position source.

When the unit is receiving a valid position input, the identifier and frequency
type will show for COM and NAV frequencies for the nearest facilities.
Waypoint types with a “+” sign will have more frequencies for the same type.

Airport Identifier Shown For

Frequencies In Database

Frequency Database Reverse Look-Up

2.4 OBS Mode

GNC 255A/255B – Page 2-8
Added information about OBS Mode.

There are four different CDI configurations, which allow the installer to
configure the GNC 255 to the type of CDI indicator that is connected. The
installer-set CDI configuration will determine the operation of the OBS Mode.

If the system is configured with an analog or digital external CDI/HSI, the OBS
radial of the remote display will be decoded and displayed on the screen of the
GNC 255.

Press the OBS key to see the current OBS setting and graphic CDI.

NOTE: The Identifier is the decoded NAV identifier from the Morse code
broadcast by the station.

If the system is configured with a composite external indicator, the OBS mode
will be unavailable. If there is no external CDI/HSI providing OBS control, the
outer and inner knobs can be used to change the displayed OBS value.

2

GTR 225/GNC 255 Series Software Version 2.10 Upgrade Supplement 190-01182-10 Rev. A