Software and Service Bulletins for pilots

Get the latest performance benefits from your Trig product

Improvements and new features are available for your Trig product through software updates. These can be carried out by an Approved Trig Dealer, or suitably qualified installer. If you would like advice about the suitability, or need to update your Trig unit, please contact your local Approved Trig Dealer. They will be able to help you and organise the upgrade of your avionics.

The current version of software installed in your Trig product will be shown on the display at initial power up. 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.

The archive folders within the sidebar contains older versions of software. Once you have viewed an archive page, use the Back Button on your browser to return to this page.

Listed below are the current Trig product Software and Hardware versions.

Please note that Trig software versions use the numbering convention <MAJOR>.<MINOR>.  The ‘.’ is not a decimal point.  For example, version 1.12 is a later version than version 1.9

TT21 AND TT22 Transponder

17/04/2018        version 2.13

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

TC20 Transponder control head 

04/09/2017       version 1.14

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


12/11/2019          version 1.12

A small number of TY91 and TY92 radios have been found to intermittently mistune the receiver frequency, although the control head has selected, and is displaying the intended channel.  The symptoms are that the wanted channel is not  received, and depending on the mistune, a different channel might be received.  If the mistuned channel is not active, the radio would appear silent.  Reselecting the channel, transmitting on the channel, or powering the radio off and on generally corrects the problem.

Software version 1.12 introduces a change to the tuning mechanism to correct this problem.  No other radio features are affected, and this software change has no effect on radios that are not experiencing this issue.


06/01/2023        version 1.8

In software versions prior to version 1.8 the step size defaults to 25 kHz whenever the TC90 is switched on. Software version 1.8 remembers the step size, and restores whichever step size was selected (8.33 / 25 / 50) each time the controller is switched on.


14/08/2019        version 1.9

Software version 1.9 makes the following changes:

1. Reduces the susceptibility to incorrect squelch opening on aircraft with very high levels of RF noise radiating from the ignition system.
2. Has minor improvements to audio performance on received signals.
3. Allows the radio to recall the previous tuning knob step size s(8.33/25h/50 kHz when turned off)
4. Corrects an error when trying to load a frequency database with more than 255 entries.

TT31 Transponder 


24/09/2018         version 3.18

TT31 software version 3.18 improves performance of Mode S replies to certain interrogations, correcting software versions 3.14, 3.15, 3.16 and 3.17.


01/10/2018          version 1.0

This Hardware Service Bulletin applies to TT31 transponders approved under ETSO authorisation EASA.21O.643 Rev B and EASA.21O.906 Rev A, part number 00220-00-(XX) and part number 00225-00-(XX) which are:

  • Serial number from 05767 to 09715;
  • Modification Level 6 or below;
  • Installed in an orientation which is NOT a conventional aft-facing avionics stack mounting.

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