DecoderPro—Three ways

I’ve been getting emails recently about updating the decoder definition files in DecoderPro, so let’s go over that. The first and easiest method is to simply go to the JMRI website ( download and install the most recent version of JMRI. In the process all the most recent decoder definition files will be installed—voila. Remember though, make a copy of your database before you do an update, just in case. That’s the first way.

The second way is to download and install the most recent version of any decoder definition files you need. This is a multi-step process so get ready to take some notes. Go to the following site ( and using your mouse right click on the name of the decoder file you want. In the options that pop up, select Download Linked File. The file will be downloaded to your computer. Next open DecoderPro and in the Files menu option select Import Decoder File and enter the location of the file you just downloaded. Be patient, it will take a while for it to complete the process and there isn’t any indication that it is doing anything at all.

The third method is easier, I promise. Just like in the second method, go to the JMRI website and click the file you want. Next copy the url of that particular file from the window at the top of your browser. Now go back to DecoderPro and the Files option. Select Import Decoder URL. The program will then download the file and install it. If the file doesn’t appear right away you may need to restart DecoderPro. And remember if you ever run into any questions there are excellent explanations of these steps and more on the DecoderPro website so take a few minutes and familiarize yourself with the details. I think you’ll find it comes in real handy on those nights when you can’t get to sleep any other way!


  • Larry,
    I have been using DP for quite some time. I have MANY Soundtraxx Tsunami2’s. Now I have quite a few Tsunami2 Release 1.2. The diesel decoder definitions have not been updated to access several some very useful CV’s namely CV223 Pitch Shift (new to R1.2). I have pondered the idea of modifying the decoder definition but greatly lack knowledge in XML coding. Have you considered writing a column covering decoder definition (XML) modification?

    I enjoy reading your columns and have gleaned useful tidbits. Thanks for your efforts!

    • Tad,
      I dont know when it was added, but pitch shift for Tsunami 2 is in the latest 4.11.4 JMRI files. It is on the sound decoder pro. It may have been added before this release, I just dont know. Another reason in my mind for me to keep getting the latest JMRI versions as they come out.

      Tom Wilson

  • TrainRev,
    Production version for Decoder Pro means they have made some particular milestones of improvements they had intended for the next major release. By and large, that is the goal of a production version. However, sometimes things can get brought in or excluded that causes issues that dont get realized until lots of people are using it. The developers are all volunteers and are excellent at what they do. But there is no in house testing ground for every possible scenario or hardware configuration. They rely on us, the users to report issues, then they can tweak and improve and the product morphs into better software for everyone. In following the JMRI group, it is my opinion that the current 4.10 production release is by and large fine for Decoder Pro only users. But if using some of the more involved features of layout control and automation, you are better off going with the latest test release – currently 4.11.3, however 4.11.4 is coming out any day now, probably this weekend. It addresses lots of bugginess in the 4.10 release.
    That said, there are some decoder pro only users that experienced slow ness and loading problems due to Windows 10 issues beyond the control of JMRI . Particularly with Windows 10 updates that started messing with audio libraries and fonts. I believe most of that has been cleared up in 4.11.3.
    Personally, I always get the latest test release and see what happens. I dont mind helping to identify issues. Besides, the test releases fix issues that were in the production releases. But do keep a backup of your files prior to updating in case you need to go back.

    There is a simple way to get settings from LokProgrammer to DecoderPro, but I wont rain on Larry’s parade. 😉

    For what its worth,
    Tom Wilson

    • Tom

      Regarding, “Production version for Decoder Pro means they have made some particular milestones of improvements ……”

      Thanks for your reply. I’m really looking forward to that issue!

  • Larry & Tom: thanks, much for those clarifications! (1) When updating, do you advise downloading JMRI’s “test releases” or just the “production” versions. (2) Also, I am using the LokSound programmer to configure their decoders (a lot simpler than using DecoderPro). Then I use DP to “read” the entire decoder to get an .xml file into my register. when making modifications to the decoder, I go back and forth, again. It’s a pain! any suggestions?


    • I typically only install production versions unless there is a compelling reason to do otherwise. Here is what they say on the JMRI website about the test versions: “Some of the changes involved are quite extensive. They may require a certain amount of experience before they are working well. Therefore, this test release should be considered experimental”. As for transferring CV settings from LokProgrammer to DecoderPro, yes there is a way and that will be in my next DCC Corner column (sorry butI can’t reveal something in an upcoming article).

  • Larry, I would just caution that as decoders have become more complex with indexed cvs, trying to import new decoder definitions into old versions of JMRI will create problems. I follow the JMRI yahoo group and one of the main help contributors who is one of the developers has advised again and again not to import just the definitions and most especially if your JMRI is over a year old.
    Tom Wilson

    • Interesting, I had not heard that. Maybe they need to put a warning on the JMRI website or remove the updating feature from DecoderPro if this is a real issue.