How to program decoders with JMRI DecoderPro
Use DecoderPro to identify a decoder, change settings through labelled screens instead of raw CV numbers, and keep a roster of every loco.
- Time
- 30 minutes per loco
- Difficulty
- Easy
- Cost
- No extra cost
- Steps
- 7
- Checked
What you’ll need
- JMRI installed and connected to your command station
- A programming track
- A decoder-fitted loco
Before you start
- Writing every CV on a sound decoder can take a while – don't remove the loco or power mid-write.
Step by step
-
Step 1: Put the loco on the programming track
Only one loco, as with any service-mode programming.
Next: step 2 -
Step 3: Identify the decoder
Click Read type from decoder. DecoderPro reads the maker and version CVs and suggests the decoder; you can also pick the model from the Decoder Installed list.
Next: step 4 -
Step 4: Fill in the details and open the programmer
Enter a roster ID (for example the loco's number) and its address, then click Open Programmer.
Next: step 5 -
Step 5: Change settings on the panes
DecoderPro groups settings into labelled panes such as basic, motor, speed table and function mapping. Change a value, then use the buttons at the bottom of the pane – for example Write sheet – to send it to the decoder.
Next: step 6 -
Step 6: Save to the roster
Click Save to Roster. The roster stores the loco's settings on your computer, so you can restore them after a reset.
Next: step 7 -
Step 7: Edit later
Select the loco in the roster list and click Program... to reopen it.
Tips
- Back up the JMRI roster folder; it's a record of every decoder setting.
- DecoderPro definitions are text files, so new decoders can be added as makers release them.
Questions people ask
My decoder isn't listed
Update JMRI or use a close match from the same maker; JMRI explains how to add or update decoder definitions.
Can I program on the main?
Yes, if your command station supports operations-mode programming; readback depends on the system (RailCom-capable systems can read on the main).
Sources
Checked 18 October 2026. We wrote this guide in our own words, using:
- JMRI DecoderPro (jmri.org)
- JMRI DecoderPro tour (jmri.org)
- NMRA S-9.2.2 Configuration Variables (July 2012) (nmra.org)
- ESU LokPilot 5 instruction manual, Edition 7 (distributor copy) (intermountain-railway.com)
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Printed from dcctrainautomation.uk/guides/program-decoders-with-jmri-decoderpro/ · Checked 18 October 2026 · General information only. Follow the maker’s instructions for your own equipment, and keep mains wiring inside properly made, enclosed power supplies.