190-00726-00 Rev. J Garmin G900X Pilot’s Guide 161AUDIO PANEL AND CNSSYSTEMOVERVIEW FLIGHTINSTRUMENTS EIS AUDIO PANEL& CNS FLIGHTMANAGEMENT HAZARDAVOIDANCE AFCS ADDITIONALFEATURES APPENDICES INDEX4.4 GTX 33 MODE S TRANSPONDER(S)The single or dual GTX 33 Mode S Transponders provide Mode A, Mode C, and Mode S interrogation and replycapabilities. Selective addressing or Mode Select (Mode S) capability includes the following features:• Level-2 reply data link capability to exchange information between aircraft and Air Traffic Control (ATC)facilities• Surveillance identifier capability• Flight ID (Flight Identification) reporting – The Mode S Transponder reports aircraft identification as either theaircraft registration or a unique Flight ID.• Altitude reporting• Airborne status determination• Transponder capability reporting• Mode S Enhanced Surveillance (EHS) requirements• Acquisition squitter – Acquisition squitter, or short squitter, is the transponder 24-bit identification address.The transmission is sent periodically, regardless of the presence of interrogations. The purpose of acquisitionsquitter is to enable Mode S ground stations and aircraft equipped with a Traffic Avoidance System (TAS) torecognize the presence of Mode S-equipped aircraft for selective interrogation.• Extended squitter – Transmits the Automatic Dependent Surveillance-Broadcast (ADS-B) position, velocity, andheading information periodically without requiring an interrogation.The Hazard Avoidance Section provides more details on traffic avoidance systems.TRANSPONDER CONTROLSTransponder function is displayed on three levels of softkeys on the PFD: Top-level, Mode Selection, andCode Selection. When the top-level XPDR Softkey is selected, the Mode Selection softkeys appear: XPDR1,XPDR2, STBY, ON, ALT, VFR, CODE, IDENT, ADS-B TX, BACK.When the CODE Softkey is pressed, the number softkeys appear: 0, 1, 2, 3, 4, 5, 6, 7, IDENT, BKSP,BACK. The digits 8 and 9 are not used for code entry. Pressing the numbered softkeys in sequence entersthe transponder code. If an error is made, pressing the BKSP Softkey moves the code selection cursor to theprevious digit. Pressing the BKSP Softkey again moves the cursor to the next previous digit.Pressing the BACK Softkey during code selection reverts to the Mode Selection Softkeys. Pressing the BACKSoftkey during mode selection reverts to the top-level softkeys.The code can also be entered with the FMS Knob on either PFD. Code entry must be completed with eitherthe softkeys or the FMS Knob, but not a combination of both.Pressing the IDENT Softkey while in Mode or Code Selection initiates the ident function and reverts to thetop-level softkeys.After 45 seconds of transponder control inactivity, the system reverts back to the top-level softkeys.
