Garmin GTX 327 Installation Manual

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GTX 327 Installation Manual Page 1190-00187-02 Rev J1. GENERAL DESCRIPTION1.1 INTRODUCTIONThis manual describes the physical, mechanical and electrical characteristics, plus the installationrequirements and operating instructions for the Garmin GTX 327 Digital Display Transponder system.Information pertaining to the maintenance, alignment and procurement of replacement parts is found inthe GTX 327 Maintenance Manual, Garmin P/N 190-00187-05. After installation of the GTX 327, FAAForm 337 must be completed by an appropriately certificated agency and ATC transponder tests requiredby 14 CFR, Part 91.413 must be completed to return the aircraft to service.1.2 EQUIPMENT DESCRIPTIONThe Garmin GTX 327 is a panel-mounted transponder with the addition of altitude reporting and timingfunctions. 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 pulsesto 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, whichdiffer in the position and number of pulses transmitted. By replying to ground transmissions or TCASinterrogations, the GTX 327 enables ATC to display aircraft identification, altitude and groundspeed onATC radar screens or TCAS traffic indicators. The GTX 327 is equipped with IDENT capability thatactivates 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 displayssegregates the transponder’s primary functions from the secondary timing functions. The unit can beconfigured so the aircraft avionics master bus can turn the unit on.1.3 MUTUAL SUPPRESSION PULSESOther equipment on board the aircraft may transmit in the same frequency band as the transponder, suchas DME or another transponder. Mutual suppression is a synchronous pulse that is sent to the otherequipment to suppress transmission of a competing transmitter for the duration of the pulse traintransmission. The transponder transmission may be suppressed by an external source and otherequipment on board may be suppressed by the transponder. This feature is designed to limit mutualinterference.1.4 INTERFACE SUMMARYThe GTX 327 provides the following interface connections via the rear connector:• Ten (10) encoding altimeter inputs.• External IDENT input.• External STBY input.• External suppression pulse input.• Switched power output of up to 1.5 amps (for digital altitude encoder power).