GTX 327 MAINTENANCE MANUAL
Page 1-1
190-00187-05
Rev. B
SECTION 1
DESCRIPTION AND OPERATION
1.1
INTRODUCTION
This manual provides functional testing and assembly level maintenance information for the GARMIN GTX 327
Digital Display Transponder System. Information pertaining to the installation and operating instructions can be
found in the GTX 327 Installation Manual, 190-00187-02. This manual is designed to aid the bench technician in
isolating failures to the assembly level only. If necessary, the GTX 327 can be returned to GARMIN for all
service work, including maintenance and repair. Contact GARMIN at the following address for more details:
GARMIN
1200 E. 151
st
Street
Olathe, KS 66062
Telephone: 913-397-8200
Dealer Line: 1-800-800-1420
Website Address: www.garmin.com
1.2
GENERAL DESCRIPTION
The GARMIN GTX 327 is a panel-mounted TSO’d transponder with the addition of timing functions. The
transponder is a radio transmitter and receiver that operates on radar frequencies, receiving ground radar
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, the GTX 327 enables ATC
to display aircraft position, identification, encoded altitude and groundspeed on ATC radar screens. The
GTX 327 is equipped with IDENT capability (IDENT key) that activates the Special Position Identification (SPI)
pulse for 18 seconds.
The GTX 327 is configured with all pushbutton 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 document reference is online, please check the correspondence between the online documentation and the printed version.
