JMRI: Select PR3 ModeA Digitrax PR3 can act either as a stand-alone programmer, or as an interface to a LocoNet, but it can only do one at a time. Normally, you choose the PR3 mode as part of setting the JMRI preferences.
In some cases, you might want to quickly change the mode during debugging. This tool provides two buttons to allow you to change the PR3's mode immediately. Note that this may result in unusual (and usually bad) behavior from the program! It's generally better to switch mode by changing the JMRI preferences and restarting the program.
For more information on the PR3, please see its JMRI reference page.