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Hardware Support: LocoNet® Simulator

If JMRI is configured to use a Digitrax LocoNet® connection, but a physical connection isn't available, several aspects of the program will not function. This is because the program needs to interact with the LocoNet during normal operation, and without the expected responses from the LocoNet it will appear basically dead.

The "LocoNet Simulator" was created to make it possible to use JMRI in a disconnected mode. This is useful e.g. if you want to develop a panel while away from your layout.

To use the LocoNet Simulator, select it as your layout connection in the preferences, save the preferences, quit and restart the program. You should then be able to access LocoNet items such as Turnouts, Sensors, Signals, etc. Some of the more advanced features, such as the BDL168 programmer, will not fully function, but you should be able to do all the steps to build and edit panels.

When your computer is connected to the LocoNet again, you can change the preferences to the proper connection, e.g. a LocoBuffer-USB, and use the panel you've created.

Hex files

The simulator can also read and playback hex traces of LocoNet activity to see how the program will react to them. Each line in the trace is a single LocoNet packet in hexadecimal characters. You can create one of these by for example turning on the "show raw data" option in a LocoNet Monitor window, and having the monitor write to a log file. You'll have to edit the resulting file to remove the human readable lines, leaving just the hex raw data.
An example hex file is shown here:

A1 0B 00 55 ↵

B0 2D 10 72 ↵
BB 10 00 54 ↵

Note that each hex value must be two valid hexadecimal characters plus a space. Each message (line) must be terminated by a carriage return. Note that there is a space immediately before the carriage return!

The sequence above would result in the following LocoNet traffic, shown as decoded by the LocoNet Monitor tool (with Raw Data displayed):

[A1 0B 00 55]  Set loco in slot 11 direction to FWD, F0=Off, F1=Off, F2=Off, F3=Off, F4=Off.
[B0 2D 10 72]  Requesting Switch at LT46 () to Thrown (output On).
[BB 10 00 54]  Request data/status for slot 16.

Because there is no Command Station, the last message would not receive a response.

Simulate replies

At the bottom of the LocoNet Simulator pane a checkbox allows activating (a limited set of) replies from virtual hardware. This option is primarily intended for developers.



The Monitor LocoNet tool captures and interprets messages on LocoNet.

Third Party info

The LocoNet® Personal Use Edition 1.0 Specification is available from the Digitrax website.

LocoNet® is a registered trademark of Digitrax, Inc.