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How to connect JMRI to your DCC layout

Install JMRI, choose the right connection for your command station and check the computer can talk to the layout.

Time
1 hour
Difficulty
Medium
Cost
No extra cost
Steps
7
Checked
Report a problem

What you’ll need

  • A Windows, macOS, Linux or Raspberry Pi computer
  • A command station with a computer interface JMRI supports
  • The right USB cable or network connection Search Amazon for USB A to B cable

As an Amazon Associate we earn from qualifying purchases. The Amazon links go to search results, so you can compare what’s available.

Before you start

  • Stop trains before changing connection settings; restarting JMRI interrupts control.

Step by step

  1. Step 1: Check your hardware is supported

    JMRI supports a long list including DCC-EX, Digitrax LocoNet, NCE, Lenz XpressNet-based systems (including Hornby and Roco), SPROG, ESU ECoS, Roco/Fleischmann Z21, MERG CBUS and LCC. Look up your system on JMRI's hardware page for its specific instructions.

    Next: step 2

  2. Step 2: Install Java and JMRI

    Download the current production release from jmri.org (5.16 at the time of writing). Releases after 4.26 need Java 11 or later. JMRI runs on Windows, macOS, Linux and Raspberry Pi OS.

    Next: step 3

  3. Step 3: Connect the cable

    For USB, connect the computer to the command station's USB or serial interface. Windows or Linux may need a driver for some adapters; JMRI notes that with DCC-EX, Macs need none.

    Next: step 4

  4. Step 4: Set up the connection in Preferences

    Open DecoderPro or PanelPro, go to Preferences, choose the System Manufacturer, then the System Connection type and the port. For DCC-EX: manufacturer DCC-EX, connection DCC-EX Serial Port for USB, or DCC-EX Ethernet with the command station's IP address and port 2560 for WiFi/Ethernet.

    Next: step 5

  5. Step 5: Save and restart

    Save; JMRI will quit and need restarting to use the new connection.

    Next: step 6

  6. Step 6: Test it

    Open a JMRI throttle window, turn track power on and drive a loco. If it doesn't connect, check the port and that no other program (Arduino IDE, EX-WebThrottle) is using it.

    Next: step 7

  7. Step 7: Try the simulator if you're not ready

    JMRI offers simulator connections for some systems (including DCC-EX and Digitrax LocoNet) so you can learn panels offline.

Tips

  • Keep JMRI profiles separate for test and real layouts.
  • JMRI's help pages are installed with the program and match your version.

Questions people ask

Does JMRI cost anything?

No. It's open source under the GPL v2 with the Classpath Exception.

Can phones connect through JMRI?

Yes – WiFi throttles are on JMRI's supported hardware list, and a DCC-EX command station with WiFi can also accept throttle apps such as Engine Driver directly.

Sources

Checked 18 October 2026. We wrote this guide in our own words, using:

  1. JMRI home page (jmri.org)
  2. JMRI copyright and licence (jmri.org)
  3. JMRI supported hardware (jmri.org)
  4. JMRI help: DCC-EX connection (jmri.org)
  5. JMRI PanelPro: Getting Started (jmri.org)

Tags: computer control DecoderPro JMRI PanelPro USB WiFi

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Printed from dcctrainautomation.uk/guides/connect-jmri-to-your-layout/ · 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.