Garmin GTX 327 User manual

£
Garmin International, Inc.
190-00187-02 Revision K
January 2005
GTXTM 327
TRANSPONDER
INSTALLATION
MANUAL

Page A GTX 327 Installation Manual
Revision K 190-00187-02
© Copyright 1999 – 2005
Garmin Ltd. or its subsidiaries
All Rights Reserved
Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted,
disseminated, downloaded or stored in any storage medium, for any purpose without the express prior
written consent of Garmin. Garmin hereby grants permission to download a single copy of this manual and
of any revision to this manual onto a hard drive or other electronic storage medium to be viewed and to
print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of
this manual or revision must contain the complete text of this copyright notice and provided further that
any unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited.
Garmin International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Telephone: [phone]
Aviation Dealer Technical Support Line (Toll Free): [phone]
www.garmin.com
Garmin (Europe) Ltd.
Unit 5, The Quadrangle, Abbey Park Industrial Estate
Romsey, SO51 9DL, U.K.
Telephone: [phone]
RECORD OF REVISIONS
Revision Revision Date Description ECO #
A 01/19/00 Initial Release 12550
B 02/28/00 Update Configuration Procedure 12785
C 06/01/00 Update Configuration Procedure. Add JTSO
references and STC form.
13450
D 07/18/00 Correct Interconnect Diagram, New RF Connector
Spacer P/N, Plus Misc Changes
13763
E 8/01/01 Add P/N’s @ Section 1.5 16263
F 11/06/01 Updates and Clarifications 16867
G 05/01/02 Updated unit and accessory part numbers 18295
H 11/01/02 Revised to reflect new software 19608
J 5/22/03 Revised to reflect Software 2.06 21163
K 01/10/05 Revised to reflect Software 2.08 29279
DOCUMENT PAGINATION
Section Page Range
Table of Contents 1-6
Section 1 1-6
Section 2 1-8
Section 3 1-2
Section 4 1-6
Section 5 1-12
Appendix A A-1-A-8
Appendix B B-1-B-6
Appendix C C-1-C-8

GTX 327 Installation Manual Page i
190-00187-02 Preliminary Revision K
This manual is written for software version 2.08, and is not suitable for earlier software
versions. The software version and information in this document is subject to change
without notice.
INFORMATION SUBJECT TO EXPORT CONTROL LAWS
This document may contain information which is subject to the Export Administration
Regulations ("EAR") issued by the United States Department of Commerce (15 CFR, Chapter
VII, Subchapter C) and which may not be exported, released, or disclosed to foreign nationals
inside or outside of the United States without first obtaining an export license. A violation of
the EAR may be subject to a penalty of up to 10 years imprisonment and a fine of up to
$1,000,000 under Section 2410 of the Export Administration Act of 1979. Include this notice
with any reproduced portion of this document.
WARNING
This product, its packaging, and its components contain chemicals known to the State
of California to cause cancer, birth defects, or reproductive harm. This Notice is being
provided in accordance with California's Proposition 65. If you have any questions or
would like additional information, please refer to our web site at
www.garmin.com/prop65.

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GTX 327 Installation Manual Page iii
190-00187-02 Preliminary Revision K
TABLE OF CONTENTS
PARAGRAPH PAGE
1 GENERAL DESCRIPTION..............................................................................................................1-1
1.1 Introduction........................................................................................................................................1-1
1.2 Equipment Description ......................................................................................................................1-1
1.3 Mutual Suppression Pulses ................................................................................................................1-2
1.4 Interface Summary.............................................................................................................................1-2
1.5 Technical Specifications ....................................................................................................................1-3
1.6 Installation Approval .........................................................................................................................1-4
1.7 Aircraft Station License Requirements..............................................................................................1-5
1.8 Reference Documents ........................................................................................................................1-5
1.9 Limited Warranty...............................................................................................................................1-6
2 INSTALLATION OVERVIEW ........................................................................................................2-1
2.1 Introduction........................................................................................................................................2-1
2.2 Installation Material...........................................................................................................................2-1
2.3 Installation Considerations ................................................................................................................2-2
2.4 Antenna Installation...........................................................................................................................2-2
2.5 Cabling and Wiring............................................................................................................................2-3
2.6 Installation Approval Considerations for Pressurized Aircraft..........................................................2-5
2.7 Cooling Air ........................................................................................................................................2-6
2.8 GTX 327 Installation .........................................................................................................................2-6
3 INSTALLATION PROCEDURE......................................................................................................3-1
3.1 Unpacking Unit..................................................................................................................................3-1
3.2 Electrical Connections .......................................................................................................................3-1
3.3 Circuit Breaker Placard......................................................................................................................3-2
3.4 Post Installation Configuration and Checkout ...................................................................................3-2
4 SYSTEM INTERCONNECTS..........................................................................................................4-1
4.1 Power and Lighting Function ............................................................................................................4-2
4.2 Altitude Functions .............................................................................................................................4-3
4.3 Discrete Inputs ...................................................................................................................................4-5
4.4 RS-232 Input/Output, Software Update Connections........................................................................4-6

Page iv GTX 327 Installation Manual
Revision K Preliminary 190-00187-02
PARAGRAPH PAGE
5 POST INSTALLATION CONFIGURATION & CHECKOUT PROCEDURE ..............................5-1
5.1 Operation..........................................................................................................................................5-1
5.2 Configuration Pages........................................................................................................................5-4
APPENDIX A CERTIFICATION DOCUMENTS
A.1 Continued Airworthiness .................................................................................................................. A-1
A.2 Environmental Qualification Forms, GTX 327 Transponder ...........................................................A-1
APPENDIX B ASSEMBLY AND INSTALLATION DRAWINGS
APPENDIX C INTERCONNECT DRAWINGS

GTX 327 Installation Manual Page v
190-00187-02 Preliminary Revision K
LIST OF ILLUSTRATIONS
FIGURE PAGE
2-1 Antenna Installation Considerations..................................................................................................2-2
2-2 GTX 327 Unit Rack...........................................................................................................................2-7
4-1 Rear Connector, J3271.......................................................................................................................4-1
4-2 Dual GTX 327, Single Encoder, Serial Input Connections ...............................................................4-4
4-3 GTX 327 Software Update Connections ...........................................................................................4-6
5-1 GTX 327 Front Panel.........................................................................................................................5-1
A-1 GTX 327 Environmental Qualification Form .................................................................................. A-6
B-1 GTX 327 Outline Drawing ............................................................................................................... B-1
B-2 GTX 327 Connector/Rack Assembly Drawing ................................................................................ B-3
B-3 GTX 327 Recommended Panel Cutout Dimensions......................................................................... B-5
C-1 GTX 327 to 400/500 Series Units, Typical Interconnect Wiring Diagram ...................................... C-1
C-2 GTX 327 to GNS 480 (CNX80), Typical Interconnect Wiring Diagram ........................................ C-3
C-3 Dual TXP Interconnect Wiring Diagram, Encoding Altitude Connections...................................... C-5
LIST OF TABLES
TABLE PAGE
3-1 Pin Contact Part Numbers..................................................................................................................3-1
3-2 Recommended Crimp Tools ..............................................................................................................3-1
3-3. Unit Power Loads ..............................................................................................................................3-6
4-1 P3271 Pin Assignments .....................................................................................................................4-1
4-2 Aircraft Power Pin Assignments........................................................................................................4-2
4-3 Aircraft Lighting Pin Assignments ....................................................................................................4-2
4-4 Encoded Altitude Pin Assignments ...................................................................................................4-3
4-5 Discrete Inputs Pin Assignments .......................................................................................................4-5
4-6 RS-232 Input/Output Pin Assignments..............................................................................................4-6

Page vi GTX 327 Installation Manual
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GTX 327 HARDWARE MOD LEVEL HISTORY
The following table identifies hardware modification (Mod) Levels for the
GTX 327 Transponder. Mod Levels are listed with the associated service bulletin
number, service bulletin date, and the purpose of the modification. The table is current
at the time of publication of this manual (see date on front cover) and is subject to
change without notice. Authorized Garmin Sales and Service Centers are encouraged to
access the most up-to-date bulletin and advisory information on the Garmin Dealer
Resource web site at www.garmin.com using their Garmin -provided user name and
password.
MOD
LEVEL
SERVICE
BULLETIN
NUMBER
SERVICE
BULLETIN
DATE
PURPOSE OF MODIFICATION

GTX 327 Installation Manual Page 1-1
190-00187-02 Revision K
1 GENERAL DESCRIPTION
1.1 Introduction
This manual presents the mechanical, and electrical installation requirements for the GTX 327 Digital
Display Mode A/C Transponder. After installation of the GTX 327, FAA Form 337 must be completed
by an appropriately certificated agency and ATC transponder tests required by 14 CFR, Part 91.413 must
be completed to return the aircraft to service.
1.2 Equipment Description
The Garmin GTX 327 is a panel-mounted transponder with the addition of altitude reporting and timing
functions. The transponder is a radio transmitter and receiver that operates on radar frequencies,
receiving ground radar or TCAS interrogations at 1030 MHz and transmitting a coded response of pulses
to ground-based radar on a frequency of 1090 MHz.
As with other Mode A/Mode C transponders, the GTX 327 replies with any one of 4,096 codes, which
differ in the position and number of pulses transmitted. By replying to ground transmissions or TCAS
interrogations, the GTX 327 enables ATC to display aircraft identification, altitude and groundspeed on
ATC radar screens or TCAS traffic indicators. The GTX 327 is equipped with IDENT capability that
activates the Special Position Identification (SPI) pulse for 18 seconds.
The GTX 327 is configured with all key controls. The layout of the front panel keys and displays
segregates the transponder’s primary functions from the secondary timing functions. The unit can be
configured so the aircraft avionics master bus can turn the unit on.
The GTX 327 can also be incorporated in installations with other compatible control/display units such as
the Garmin GNS 480 (CNX80).
Provision is made for unit software upgrade by means of RS-232 data transfer through rear connector
pins. The installation of an optional connector is highly recommended. If the optional connector is
placed in the aircraft, transponder removal and reinstallation for software upgrade is not required. The
software can be changed while the unit is still mounted inside the aircraft.
CAUTION
The GTX 327 lens is coated with a special anti-reflective coating, which
is very sensitive to skin oils, waxes and abrasive cleaners. CLEANERS
CONTAINING AMMONIA WILL HARM THE ANTI-REFLECTIVE
COATING. It is very important to clean the lens using a clean, lint free
cloth and an eyeglass lens cleaner that is specified as safe for
anti-reflective coatings.

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Revision K 190-00187-02
1.3 Mutual Suppression Pulses
Other equipment on board the aircraft may transmit in the same frequency band as the transponder, such
as DME or another transponder. Mutual suppression is a synchronous pulse that is sent to the other
equipment to suppress transmission of a competing transmitter for the duration of the pulse train
transmission. The transponder transmission may be suppressed by an external source and other
equipment on board may be suppressed by the transponder. This feature is designed to limit mutual
interference.
1.4 Interface Summary
The GTX 327 provides the following interface connections via the rear connector:
•Ten (10) encoding altimeter inputs.
•External IDENT input.
•External STBY input (useful for dual transponder installations).
•External suppression pulse input.
•Switched power output of up to 1.5 amps (for digital altitude encoder power).
•Aircraft power input (11 to 33 Volts).
•Aircraft dimming bus input voltage.
•Aircraft master switch turn-on option.
•Serial airdata or GPS groundspeed input.
•Serial altitude input. (Reduces wire count vs. parallel wire gray code altimeter interface.)
•Software update input.