Garmin GTXTM 327 TRANSPONDER INSTALLATION MANUAL
Brand: Garmin, Pages: 55
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Page 28 GTX 327 Installation Manual
3.3.5 RS-232 INPUT/OUTPUT Page
This is the electrical source for the GTX 327 altitude and
GPS data input. Refer to paragraph 184.108.40.206 for altimeter
data selection priority.
RS-232 INPUT (Altitude Source, GPS Data)
OFFDEFAULT. The altitude code input is not from an RS-232 source.
GPSRS-232 ground speed from a GPS device.
ICARUS ALTRS-232 serial altitude from an Icarus Instruments 3000.
ADC NO ALTRS-232 serial air data information from Shadin ADC 200, 200+, 2000.
ADC W/ALTRS-232 serial air data information from Shadin ADC 200, 200+, 2000 plus
SHADIN ALTRS-232 serial altitude from Shadin 8800T, 9000T, 9200T.
FADC NO ALTRS-232 serial air data from Shadin 9628XX-X family of Air Data
Computers and Fuel/Air Data Computers.
FADC W/ALTRS-232 serial air data from Shadin 9628XX-X family of Air Data
Computers and Fuel/Air Data Computers plus altitude data.
REMOTERS-232 serial input remote data. Reserved for future use.
RS-232 OUTPUT (Altitude Out)
OFFNo RS-232 output from this channel.
ICARUS ALTDEFAULT. RS-232 serial altitude from an Icarus Instruments 3000.
REMOTERS-232 serial output remote data. Reserved for future use.
RS-232 INPUT/OUTPUT Page
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GTX 327 Installation Manual Page 29
3.3.6 OPERATION CONFIGURATION Pages
220.127.116.11 First Configuration Page
VS RATE (Vertical Speed Rate)
This field is the typical vertical speed for climb/descent of the aircraft. This number determines when a
climb or descent arrow is displayed on the PRESSURE ALT page of the GTX 327. The range is 0 (zero)
feet per minute to 9999 feet per minute. It is set to 500 fpm at the factory.
FLT TMR (Flight Timer)
Available choices are MANUAL, CLEAR and ACCUMULATE. Selecting CLEAR resets Flight Time to
zero and starts the flight timer when lift off is sensed.
MANUALFlight timer START/STOP is controlled manually by the pilot.
CLEARDEFAULT. Automated flight timer START/STOP resets to zero at every
ACCUMULATEAutomated flight timer START/STOP continues counting up at lift off.
VFR ID (VFR Transponder Code)
This field is the four-digit code that will be selected when the user presses the GTX 327 VFR key. In the
United States, 1200 is the VFR code for any altitude. Many European countries use 7000 as the VFR
code. It is set to 1200 at the factory.
FORMAT (Altitude Format)
This field determines how the pressure altitude will be shown on the GTX 327 display.
(Flight Level)DEFAULT. The pressure altitude is displayed in hundreds of feet.
For example, a pressure altitude of 12,300 feet is displayed as “FL
FEETPressure altitude is displayed in feet.
METERSPressure altitude is displayed in meters.
First Configuration Page
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Page 30 GTX 327 Installation Manual
18.104.22.168 Second Configuration Page
The GTX 327 Flight Time may be based on the squat switch state. The squat switch field may be set to
either YES or NO. (Default NO). If YES, sense may be set to HIGH or LOW. If set to NO, airborne
status for auto standby and flight timer features will be determined by input data. The highest priority is
GPS groundspeed. The next is serial port ADC input followed by pressure altitude change, if no other
RS-232 source is available.
SENSE (Squat Switch Sense)
This field can only be entered if the AIRBORNE SOURCE selection is YES.
LOWDEFAULT. The installed squat switch or airspeed switch is low
(grounded) when the aircraft is on the ground, and open when airborne.
HIGHThe installed squat switch or airspeed switch is open when the aircraft is
on the ground, and low (grounded) when airborne.
OFFSelection of STBY (standby) and ALT (altitude-reporting) modes is
initiated manually by the pilot.
ONDEFAULT. The GTX 327 will automatically transition from STBY to
ALT when the unit determines the aircraft has become airborne. When
the unit determines the aircraft has been on the ground ("ground-borne")
for the configured delay time (see "Delay Time", below), the unit will
automatically transition from ALT (or ON) to STBY.
This is the number of seconds the aircraft must be on the ground before the AUTO STBY feature
automatically switches the unit to STBY mode. Delay Time has a range of 0 (zero) to 99 seconds, and is
set to 24 seconds at the factory. When the unit is configured with a SQUAT SWITCH, an additional air-
state delay time (4.5 seconds for fixed-wing; 1 second for rotorcraft) is added to this user-configured
delay time for ground-borne determination.
Second Configuration Page
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GTX 327 Installation Manual Page 31
3.3.7 AIRCRAFT TYPE Page
AC TYPEUNKNOWN, <15.5K, >=15.5K, or ROTOR.
Used for Automated Airborne Determination (time to STBY, required airspeed, ground speed). Sets the
AIRCRAFT TYPE to ROTOR, to a weight of less than 15,500 pounds, more than or equal to 15,500
pounds, or unknown weight. Defaults to less than or equal to 15,500 pounds.
3.3.8 RS-232 INPUT VIEW Page
Depending on the selected inputs on Channel 1 and Channel 2, this page displays the information
received on the channel. If GPS is selected as an input, ground speed (GSPD), latitude (LAT), longitude
(LON) and track (TRK) can be viewed.
If ICARUS or SHADIN-ALT is selected as an input, pressure altitude (PALT) can be viewed.
If SHADIN-FADC or SHADIN-ADC is selected as an input, true or static air temperature (SAT), outside
or total air temperature (TAT), indicated air speed (IAS), true air speed (TAS), density altitude (DALT),
pressure altitude (PALT), current barometric pressure (BARO) and vertical speed (VSPD) can be viewed.
3.3.9 GRAY CODE INPUT Page
Information on this page may aid in installation
troubleshooting. There are no user inputs or operations on
This field shows the status (1 = ground, 0 = open) of each of the ten gray code altitude inputs. This
information may aid in installation troubleshooting. This page is not used in systems that contain serial
This field displays the gray code altitude input in feet. Verify that it is the correct altitude.
AIRCRAFT TYPE Page
RS-232 INPUT VIEW Page
GRAY CODE INPUT Page
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Page 32 GTX 327 Installation Manual
3.3.10 EXTERNAL SWITCH Page
Displays the state of the external switch discrete inputs.
Displays the state of the EXTERNAL IDENT discrete input. The box is filled when EXTERNAL
IDENT is grounded.
Displays the state of the EXTERNAL STANDBY discrete input. The box is filled when EXTERNAL
STANDBY is grounded.
Displays the state of the SQUAT SWITCH input. The box is filled when the SQUAT SWITCH input is
active (the aircraft is on the ground as configured on the Second Configuration page).
3.3.11 ANALOG INPUT Page
The Analog to Digital Converter (ADC) counts are shown on the display, providing troubleshooting data.
There are no user inputs or operations on this page.
Displays the current 14 Volt lighting bus ADC level.
Displays the current photocell ADC level.
Displays the current LCD temperature ADC level.
Displays the current 28 Volt lighting bus ADC level.
Displays the current reply active ADC level.
Displays the current unit temperature ADC level.
EXTERNAL SWITCH Page
ANALOG INPUT Page