190-00734-11 GTX 33X and GTX 3X5 ADS-B Maintenance ManualRev. 6 Page 2-12 SYSTEM DESCRIPTION2.1 GTX 330/330D ................................................................................................................... 2-22.2 GTX 33/33D ....................................................................................................................... 2-42.3 GTX 335/335R ................................................................................................................... 2-62.4 GTX 345/345R ................................................................................................................... 2-82.5 GTX 335R/345R with Legacy G1000 .............................................................................. 2-102.6 Electrical Load Information.............................................................................................. 2-11Garmin GTX 33X and GTX 3X5 units operate on radar frequencies, receiving ground radar or TCASinterrogations. The GTX transmits a coded response of pulses to ground-based radar on a frequency of1090 MHz. Each unit has IDENT capability and replies to ATCRBS Mode A, Mode C and Mode SAll-Call interrogation. The GTX 345/345R units include ADS-B In which provides TIS-B and FIS-B datavia UAT and 1090 MHz. The GTX 3X5 units offer an optional Garmin altitude encoder to meet therequired barometric pressure altitude source and an optional internal GPS/SBAS source to meet therequired GNSS position source integrity for ADS-B Out.The Garmin transponders approved by this STC are in the family of GTX 33X and GTX 3X5 transponders.The ES option of the GTX 33X units provides ADS-B extended squitter functionality.The GTX 33X models include: GTX 33 GTX 330 GTX 33D GTX 330DThe GTX 3X5 units all provide ADS-B Out functionality. GTX 345/345R units provide ADS-B In.The GTX 3X5 models include: GTX 335 GTX 345 GTX 335R GTX 345RADS-B technology improves situational awareness and flight safety. A Garmin transponder with ADS-Bcapabilities will automatically transmit position, velocity, and heading information to other aircraft andground stations. The current air traffic control system depends on a transponder request for pertinentaircraft information, whereas ADS-B provides automatic transmission of aircraft information without arequest.
