I recently, finally, dove into DCC at home by buying a Digitrax Zephyr Xtra and a Digitrax PR3. I've had a number of decodered locomotives for the significant amount of time I spend "visiting" or on NTRAK layouts, so I was familiar with the basic concepts, but had never got it running at home. Here's what I did, because I didn't find any nice, concise, step by step, walkthroughs, and I figured people my appreciate one.
Here's what I started with to make it all happen.
This is an easy one, open everything up, the Zephyr, the PR3, and the Mac.
First setup your Zephyr. I'd suggest everything's working fine there before moving on to the next step. Use it as it's suggested, run some stuff, etc...
Then, using the Loconet cable, connect the PR3 (either Loconet port is fine) and the Zephyr (again, either port is fine). You should now see the status lights on the PR3 blink intermittently. Please note, you do NOT need to use a power source for the PR3, for our uses it's self powered.
Now, using the USB cable, plug the PR3 into the Mac. It's going to say something like "new network connection found, usb/cu.something". Just hit ok and ignore it. You're now all connected.
There are a number of ways to do this once you've got JMRI setup, but the I usually do it by opening DecoderPro. DecoderPro is the application that lets you program decoders. Once the small screen is open (that says "DecoderPro" and has the two programming mode buttons), click the "Edit" menu, then select "Preferences".
Now, configure JMRI to talk to Loconet. Create a new connection if one doesn't exist. Use the following settings:
Hit save, and it will ask you if you want to shut down JMRI to restart it. You do. Once it's closed, relaunch JMRI, and you should be connected and ready to go. If you're not, check this thread on the JMRI user group, because there is, for a short while, a patch that needs to be applied when using the DCS51.
Now that everything is setup, give it a test. From the same "DecoderPro" window as above, select "LocoNet", then "Monitor Loconet". This is an extremely helpful window that lets you watch the traffic on Loconet (it is a network, after all), and is a great troubleshooting thing to see what's going on. When you click "start logging", you will then be able to see all the commands being sent back and forth. It's actually pretty fascinating to watch, but you're here to run trains, so let's go do that.
From the DecoderPro main window, select "Tools", "Throttles" then "New Throttle". This will open up a throttle window. Select a locomotive, or enter the address of one and hit "Set". You should now be able to control your locomotive from the on screen controls.
Ok, so being able to run a train from your computer is nice, but you can't carry a laptop around the layout room. You CAN use a mobile device to do it though. Once you have JMRI working, it's incredibly easy.
Get the "Engine Driver" app from your App Store. The Droid version was free, but I've heard there's a paid version. Either way, it's gonna save you a bunch of money.
From the main JMRI window, select "Tools", "Throttles", "Start WiThrottle". Now, fire up your app. As long as you're on the same wireless network as your computer, you should see it advertised. Select it. Now select a locomotive, or enter a decoder address, and you're ready to go.
The JMRI Yahoo! Group is incredibly active and helpful. If you have questions, ask there!
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