AXP340 Mode S Transponder

AXP340 Mode S Transponder

Part No:

Manufacturer: AVIDYNE

The AXP340 transponder is a panel-mounted Class 1 Mode S Level 2 Datalink transponder, with support for 1090MHz Extended Squitter (ES), that meets all the current requirements for Mode S elementary surveillance transponders for both IFR and VFR flight.  As a slide-in replacement for existing KT76A/KT78A transponders, the AXP340 is designed to easily upgrade existing Mode A/C equipment to Mode S, while adding additional functionality like a Direct-entry Numeric Keypad, Pressure Altitude and GPS Lat/Lon readout, Flight ID entry, one-touch VFR code entry, an easy-to-use Stopwatch Timer, Flight Timer and Altitude Alerter.

The AXP340 also supports the latest Version 2 1090 MHz Automatic Dependent Surveillance Broadcast (ADS-B) Extended Squitter, known as “ADS-B out”. Equipping with ADS-B Out will be required in most U.S. airspace by 2020. The AXP340, when linked to a suitable GPS receiver, transmits position information to appropriately-equipped ground stations and other aircraft. This provides improved airborne surveillance, provides vital information for airport ground surveillance, and is a key feature of future airspace plans.

The AXP340 delivers 240 Watts of transmitter power, and responds to both legacy Mode A/C interrogations and to Mode S interrogations from both ground radar and airborne collision avoidance systems. In the Mode S environment (S stands for Select), a Mode S interrogator can selectively address a single transponder. This allows accurate position plotting with lower reply rates, which in turn reduces frequency congestion and interference.

Coupled with any of Avidyne‘s TAS600A ADS-B capable Traffic Advisory Systems, the AXP340 provides full ADS-B surveillance capability to meet the upcoming mandates for flight internationally and above and below FL180 in the U.S. The AXP340 transmits the required ADS-B Out signals including your aircraft’s GPS-derived position, along with ground track, ground speed and altitude information. The TAS600A provides ADS-B In, allowing you to receive the ADS–B signals from ground radar and from other 1090MHz ADS-B – equipped aircraft and display both ADS-B and non-ADS-B traffic simultaneously for optimal situational awareness and safety.

The AXP340 provides an affordable and lightweight Mode S Surveillance and ADS-B Out solution for fixed wing and helicopter operators.

The AXP340 is a slide-in replacement for the venerable KT76A transponder, making it a great choice for upgrades, as well as for new installations. (Additional wiring required for ADS-B functionality.)

Width: 6.30" (160mm)
Height: 1.57" (40mm)
Depth: 9.4" (239mm)


2.98 lbs (01.35 kg)


Class 1 Mode S Level 2 Datalink
Elementary Surveillance
Enhanced Surveillance


TSO C112c, TSO C166b 
ETSO 2C112b, ETSO C166b


ED73B, DO160E, DO178B level B, DO181C, DO260B, AC 20-165 


10 – 33 V
Idle: 0.22 A, Active: 0.45 A
240W nominal at connector


-20 to +55 C, 35,000ft.
No external cooling fan required.

 GPS Compatibility

Avidyne GPS (including R9)
Garmin GNS430W/530W Series
Garmin GTN650/750 Series
FreeFlight Model 1201/1204
NexNav mini-T

 Other Interfaces

Gray Code & Serial Altitude Inputs
Serial Altitude Output
External Standby Input
Weight on Wheels Input
External Ident Input


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