TT21/TT22 Service Bulletins for pilots

TT21 and TT22 Transponders

Software versions run numerically, the higher the number the more recent the release – so the latest software will always include all the features of earlier versions.

29/02/2024         version 2.15 – Current software version

Some versions of the popular IFR6000 transponder test set incorrectly report a failure for Mode S side lobe suppression (SLS) on some TT21/TT22 transponders. This is caused by small variations in the way that the IFR6000 simulates the ground radar signals and is model and serial number dependent. Software version 2.15 improves compatibility with these test sets.

17/04/2018         version 2.13

This software improves GPS-only air/ground determination algorithm for ADS-B Out.

04/09/2017        version 2.12

This software adds support for Trig TN72 as a 14 CFR 91.227 compliant ADS-B position source and adds GPS only air-ground determination algorithm for ADS-B Out.

24/03/2017        version 2.11

This software improves general transponder behaviour in gliders implementing ADS-B. 2.11 also adds some minor performance improvements.

28/10/2016        version 2.10

This software adds compatibility with GPS position sources, such as the Trig TN72.

11/06/2015         version 2.7

This adds compatibility with Garmin’s ADS-B Plus protocol for GNS and GTN navigators. This allows these Garmin units to be used as the GPS source for certified ADS-B Out. Additional support added for Trig ADS-B protocol, this allows Avidyne’s IFD440/540 to be used as the GPS source for ADS-B. Certain transponder warning messages will clear when the warning conditions are no longer present.  Introduction of support for TSO-C199 TABS GPS position sources.

14/09/2012         version 2.4

Updates ADS-B Extended Squitter functionality to RTCA DO-260B standard (required by 14 CFR 91.227). New interfaces added for Garmin 4X0W and 5X0W and further interface improvements made.

09/03/2010         version 1.4

This software adds the ability to receive TIS ‘A’ traffic in relevant US airspace.

30/06/2009         version 1.2

This version improves transponder operation in high temperature environments.