JMRI Hardware Guide: Digitrax DCC

LocoNet® Connections
PR2 and PR3 Programmers
Setup
Using JMRI with LocoNet®
LocoNet® Conenction Limitations
Networked Computers and LocoNet®
Debugging
See Also

LocoNet® Connections

JMRI software, 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 ® adapter.

Supported Command Stations

JMRI software supports the following LocoNet®-based command stations:

Zephyr Starter Set
Zephyr Xtra Starter Set
Super Empire Builder Set
Chief Starter Set
Super Chief Set
Super Chief Xtra Set
DCS50 Command Station/Booster/Throttle
DCS51 Command Station/Booster/Throttle
DB150 Command Station/Booster
DCS100 Command Station/Booster
DCS200 Command Station/Booster
Intellibox: The Uhlenbrock Central Unit
DCC-Mux: DCC data combiner with built-in LocoNet® command station

For systems which do not provide a LocoNet® command station, two additional options are supported. When a layout uses LocoNet® peripheral devices but not a LocoNet®-based command station, a "Standalone" LocoNet® is used. See Standalone LocoNet®. In addition, JMRI software may be configured to use a simulated LocoNet® connection instead of a real LocoNet® connection. This is the "LocoNet® Simulator".

Supported Computer Interfaces

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 computer interface solutions. The LocoBuffer II and original LocoBuffer are no longer commercially available; their primary advantage now is that they use a traditional serial port, which may be the only suitable connection type available on some older computers.

The MS100 is not recommended; it sometimes fails to provide reliable communications, and it cannot be used with JMRI if you are using MacOS X or on most Windows Vista machines. If you have problems with the MS100, you might not be able to fix them, and nobody may be able to help you.

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 stand alone programmer. There is more information on the PR3 setup page.

Setup

To connect your computer to a Digitrax DCC system, you need a LocoBuffer-USB, PR3, LocoBuffer-II, LocoBuffer, or MS100 to act as an adapter. See below for more information on these. The LocoBuffer-USB is highly recommended.

Note that except for the PR3, these are only LocoNet® interfaces, not stand alone programmers like the Digitrax PR2 and PR3. None of these except the PR3 will let you read CVs if you have an Empire Builder! For that you need a Chief or Zephyr command station.

Connect your adapter to the LocoNet®, and connect your computer to it with the appropriate serial or USB cable.
Mac and Windows users should install the proper USB drivers if they are using USB devices.
Linux and Mac users should be sure that the correct Java communications packages have been installed.
Open a JMRI program and go to the "Preferences" panel. This normally opens automatically the first time each program is run, or you can select it from the "Edit" menu.
Select "LocoNet LocoBuffer-USB", "LocoNet MS100", or your device from the top selection box. You can then select the proper serial port in the second selection box. Check in your system hardware information if you are not sure which port to select.
The baud rate box will be fixed and grayed out if you've selected LocoBuffer-USB, PR3, or MS100. There are two speed choices for the LocoBuffer and LocoBuffer-II; select the one that corresponds to the jumper settings on your LocoBuffer unit. We recommend that you start with the 19,200 choice for the LocoBuffer or LocoBuffer-II; see the LocoBuffer-II and LocoBuffer pages for more information.
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 LocoBuffer-USB, PR3 or MS100.
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.To read CV's in conjunction with a DB150 use the PR3 in programming track mode.
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.
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. If you are the primary user of this system we suggest you set this to "Comprehensive".
Click "Save". You'll be asked if it's OK for the program to quit, click "Yes".
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 route/switch output when not in trinary" option off. (T) 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.

Using JMRI with LocoNet®

JMRI provides a number of features which allow it to interact with LocoNet®.

Many LocoNet® devices can be directly addressed by JMRI, such as the individual turnout outputs on a DS54, or the individual block detection inputs on a BDL16x. For more information on how to find those addresses, see this page.
JMRI provides a variety of LocoNet®-related tools. These primarily allow configuration of LocoNet® device functionality, but also include some tools for status monitoring. Information on these tools can be found at the LocoNet® tools page.

Networked Computers and LocoNet®

There are several mechanisms available to allow multiple computers to communicate with LocoNet®. These communicate via standard TCP/IP protocols, and can even work remotely. At least one of the networked computers must have a functioning LocoNet® interface. See this page for more information.

LocoNet® Conenction Limitations

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 should be connected to the LocoNet®-T connection.

PR-1 not supported - Note that DecoderPro cannot directly program decoders via a PR1 programmer. JMRI supports decoder programming either via the PR3 as a stand-alone programmer or via a command station.

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 LocoBuffer-USB instead.

Microsoft Vista and the MS100 - It has been reported that Vista does not support the special baud rate used by the MS100. If you find that your MS-100 does not work on your Vista machine you should get a LocoBuffer-USB or PR3 instead.

Debugging

When using the LocoBuffer or LocoBuffer-II, be sure that the JMRI preferences for the connection are set to use the same Baud rate as the LocoBuffer or LocoBuffer-II.
On Windows O/S machines, be sure that the JMRI connection is set to use the correct COM port. Use Windows "Device Manager" to help determine which COM port your interface hardware is using, then verify that JMRI is configured to use that COM port.
On Windows platforms, the COM port assignment can change if the interface hardware is moved from one USB port on the computer to another USB port. Avoid changing how your LocoNet®-to-computer interface is connected to the computer.
On Windows platforms, the COM port assignment can change if the interface hardware is connected via a USB hub. At Windows start-up, the computer can assign different COM port numbers to devices downstream of USB hubs, even if all of the USB hardware connected in the system has not been changed. Avoid connecting your LocoNet®-to-computer hardware downstream of a hub. Note that a computer monitor which has USB connectors, and which is connected to a PC using a USB cable is considered to have a built-in USB hub.
Some PR3 devices were shipped with poor quality USB cables. These cables have been known to cause a computer to fail to communicate with the PR3 or to have intermittent communication. Users should consider replacing the original USB cable from the PR3 with a known-good USB cable.
Some mobile decoders will only allow proper readback of CV values when there is a sufficient electrical load connected to the F0F (front headlamp) output connections or the motor connections. This means that an incandescent lamp or LED is properly connected to the front headlamp connection and functional. Other mobile decoders will only provide proper CV readback when a motor is connected to the mobile decoder motor connections. Consult the documentation for your mobile decoder to determine what connections are required to allow proper CV readback.
Some Digitrax hardware is capable of successful CV read and write operations on some mobile decoders but is unable to reliably read and/or write CVs for other mobile decoders. This problem is most obvious with sound decoders from some manufacturers. Some suggestions are listed here.
- When using a Zephyr (DCS50) or Zephyr Xtra (DCS51), enable its "Blast Mode" programming feature. This will often allow correct writing of mobile decoder CV values.
- "Programming on the main" can allow a Chief (DCS100 or DCS200) to properly write to difficult mobile decoder's CV values.
- A programming booster, such as the SoundTraxx PTB-100 or the DCC Specialties Power Pax can often be used between the command station programming track connections and the programming track to allow successful read and write access of CVs on mobile decoders which do not allow readback on a programming track connected directly to the programming hardware.

Support

Support for Digitrax hardware products is available through Digitrax, Inc. Digitrax product manuals may be found here. Note that Digitrax does not provide support for JMRI software.

Many knowledgable Digitrax users contribute to the Digitrax User's "Yahoo Group". If you have a problem with Digitrax equipment, this is a good place to pose your Digitrax-specific problems. This user's group is run by and for Digitrax users. It is not directly supported by Digitrax.

For JMRI-specific questions, including questions about how JMRI and Digitrax hardware interact, the JMRI Users "Yahoo group" is very helpful.