Skip to main content

JMRI Hardware Guide: Digitrax DCC

LocoNet Connections

JMRI, including DecoderPro and PanelPro, works with your Digitrax command station to program decoders. To do this, it communicates with the command station over the LocoNet using one of several types of LocoNet adapter.

DecoderPro will work with all the following command stations:

To connect your computer to the LocoNet, and hence to the command station, you need one of the following adapters:

Generally, any of these can be used with any type of computer to communicate with any type of command station. Currently, the LocoBuffer-USB and PR3 are the recommended solutions. The LocoBuffer II and original LocoBuffer are no longer being actively produced; their only advantage now is that they use a traditional serial port rather than USB. The MS100 is not recommended; it sometimes fails to provide reliable communications, and cannot be used with JMRI if you are using MacOS X or on most Windows Vista machines.

The Uhlenbrock Intellibox can also be controlled directly through it's serial port; there's a separate page on how to do this.

PR2 and PR3 Programmers

JMRI can also use a Digitrax PR2 or PR3 to program and test decoders. The PR2 is a stand-alone unit which does not connect to the rest of the layout, the command station, nor to a LocoNet. For more information on using a PR2 with DecoderPro, please see the PR2 setup page. The PR3 can either serve as an interface (see above) or as a standalone programmer. There is more information on the PR3 setup page.

Setup

To connect your computer to a Digitrax DCC system, you need a LocoBuffer II, LocoBuffer or MS-100 to act as an adapter. See below for more information on these. The LocoBuffer II is highly recommended.

Note that these are LocoNet interfaces, not standalone programmers like the Digitrax PR1. Neither of them will let you read CVs if you have an Empire Builder! For that you need a Chief or Zephyr command station. (We're working on PR1 support, and would welcome help).

  1. Connect your adapter to the LocoNet, and connect your computer to it with the appropriate serial cable.
  2. Then go to the preferences panel of a JMRI-based program. This opens automatically the first time a program is run, or you can select it from the "Edit" menu.
  3. Select "Digitrax MS100" or "Digitrax LocoBuffer" from the top selection box. You can then select the proper serial port in the second selection box.
  4. The baud rate box will be fixed if you've selected an MS100. There are two choices for the LocoBuffer; select the one the corresponds to the jumper settings on the LocoBuffer board. We recommend that you start with the 19,200 choice for the LocoBuffer and LocoBuffer II; see the LocoBuffer II and LocoBuffer pages for more information.
  5. The fourth box should be left on "hardware flow control" unless you later consistently get a message about the LocoBuffer control leads being improperly set up, in which case you might want to try to bypass that by selecting "no flow control". This box will be blank if you've selected MS100.
  6. In the fifth box, select the type of command station you have. Note that this program can't read decoder CVs if you have an Empire Builder (DB150); that's due to the Empire Builder hardware, and there's nothing we can do about it.
  7. The series of radio buttons labelled "GUI style" allows you to select how the program will look. "Metal" is the native Java look available on all types. Other choices will vary with your computer type. "Motif", "Windows", "MacOS" and "MacOS Adaptive" look native on Linux, Windows, MacOS "Classic" and MacOS X respectively.
  8. In the bottom selection box, you can pick the default programmer format. You can override this each time you open the programmer, so this is here just for convenience.
  9. Click "Save". You'll be asked if it's OK for the program to quit, click "Yes".
  10. Restart the program. You should be up and running.

If you are going to control turnouts, signals or other devices on your layout from JMRI or another program, we recommend that you set the command station's "Meter Switch Commands" option off. When on, this option greatly reduces the number of commands the LocoNet can handle each second, which can cause significant delays when you're controlling signals, etc. To turn it off, you can use the "Configure Command Station" tool in the LocoNet menu to set Option Switch 31 to "T" (thrown), or set it directly in the command station using a Digitrax throttle.

Network Connections

There are several methods available to connect multiple computers to a single LocoNet. These communicate via standard TCP/IP protocols, and can even work remotely. For more information ...

Limitations

PR-1 not currently supported - Note that DecoderPro cannot directly program decoders via a PR1 programmer. You have to use one of the command stations above.

MacOS X and the MS100 - Because MacOS X can't communicate at the special baud rate used by the MS100, the MS100 won't work with MacOS X. You should get a LocoBufffer II instead.

Serial ports on older Macintoshes and the MS100 - A standard Macintosh RS422 serial port will not work directly with an MS100. Since it doesn't have two output status lines (DTR and RTS), it can't provide correct power to the MS100. It may be possible to provide external power; if you're interested in trying this, we'd be happy to help work out a solution. A LocoBuffer will work fine with a standard Macintosh RS422 serial port.

Apple USB connections - DecoderPro is tested with both a MS100 and a LocoBuffer on a USB Macintosh using a Keyspan PDA Adapter to provide the serial port; for information please see http://jmri.sourceforge.net/DigiTrax/KeyspanAdapters/KeyspanUSB.shtml. Note that we've had a report that certain models of the PDA adapter don't work at 57,600 baud with the LocoBuffer, so please try 19,200 baud if you're having trouble.

See our page on USB adapters for more information

Uhlenbrock Intellibox - The Intellibox has two LocoNet connections, called LocoNet-T and LocoNet-B. The LocoNet-T connection can drive more devices, but does not provide the Rail-Synch signals that some LocoNet devices (particularly the BDL-16, -162 and -168) require. A LocoBuffer II should be connected to the LocoNet-T connection if it is configured to take power from the LocoNet.

Debugging

Digitrax Manuals