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Digitrax: PR3 USB Computer Interface

by Norm Stenzel

Our resident Digitrax expert Norm takes a look at the nice features of the Digitrax PR3!

Years ago if you had told me that I would have a computer hooked up to my model railroad, I would have laughed you out of the room. Now I not only have a computer hooked up to my railroad but I would be hard pressed to operate my model railroad without it!

DCC has opened the door to all the possibilities that modern electronics and the computer have to offer. The computer can be used for simple tasks such as programming our decoders and can be taken all the way to complete layout automation. I fall in between those two extremes. Like a lot of people I use the computer to program CV values in my decoders and I use it to download new sounds into some of my sound decoders (more on that later). While I have no interest in automating the trains themselves, the computer has become an indispensable tool for handling the logistical needs of operating my model railroad. I use it to control routes in and out of the staging yards. It controls my signaling system. I even use it to handle things like crossing gates and layout lighting. I’m always finding new things for the computer to handle on the railroad to make the operation more prototypical. The computer has become a hobby within the hobby of model railroading.

Digitrax: PR3 USB Computer Interface

To make all this happen, there has to be a connection between your DCC system and the computer. For those of us that use Digitrax LocoNet systems, Digitrax has the PR3 USB Programmer/Interface.

The PR3 combines the functions of the venerable Digitrax Serial devices MS100 interface and the PR2 Programmer into one neat package for USB.

The PR3 comes with complete installation instructions, the PR3, a 48” USB connecting cable to hook to your PC and a mini CD with the necessary drivers and software for your PC. You can also go to the Digitrax website and download at: http://www.digitrax.com/prd_compint_pr3.php

The PR3 can operate on a PC with Windows 2000, XP or Vista. MAC users can use the PC emulator mode (there is a PDF help file for this on the disc). At present there is no driver for Windows 7.

It is important that you follow the instructions that come with the PR3 when you install and setup your software. Digitrax has this note in the instructions: Regardless of your Windows version, the PR3 requires that Windows use the device driver that is shipped on the PR3 Installation CD. Do not let Windows attempt to install the software drivers automatically – direct Windows to install the software driver from the specific Windows version directory on the Digitrax-provided PR3 installation CD. If you follow this, you will avoid hours of frustration during the installation process (take it from someone who found out the hard way).

Modes of Operation

The PR3 has three different modes of operation.

MS-100 Mode allows the PR3 to be a LocoNet interface between your Digitrax DCC system and your PC. When using MS-100 mode no aux power supply is necessary.

Programmer Mode allows the PR3 to be a stand-alone programmer using either the Digitrax Soundloader Programming software (included on the installation CD) or 3rd party software such as JMRI DecoderPro. http://jmri.sourceforge.net/. The PR3 requires a separate power supply such as the Digitrax PS-14 or Tony’s TTE-XDTX (not included with the PR3). This plugs into a barrel socket on the PR3.

LocoNet Termination Mode allows the PR3 to interface with LocoNet when there is no Digitrax Command Station present. Do not turn on LocoNet Termination Mode when LocoNet is connected to a Command Station.

There are two push buttons to configure the PR3 and three LEDs to tell you what it is doing. These are explained in the instructions.

Using the PR3

Up till now I have been using “Loco Buffer USB” for my LocoNet/PC interface. I use Railroad & Co software in conjunction with my Digitrax Super Chief to control the different operations on my Model Railroad. I plugged the PR3 into my PC’s USB port in place of the Brand X interface and connected LocoNet from the layout to the PR3 using one of the two LocoNet sockets on the PR3 (Either one is fine). The PR3 was set to MS-100 Mode. I had to change the COM port setting in RR & Co so it would operate with the PR3. This will vary on each PC. I was able to operate everything on the railroad without any problems. The PR3 is ‘Buffered” so that it doesn’t loose any communication from the PC to the railroad or from the Railroad to the PC. I tried it using JMRI DecoderPro using the command station programmer. This also worked perfectly.

Next, I tried the PR3 in Programmer Mode. In this mode I connected my 12 volt power supply to the PR3. Then plugged in the USB cable to my PC. Two wires connect a piece of track to the programmer. First I tried the Digitrax SoundLoader software. This software allows you to program or Download sound to the Digitrax line of sound decoders. You can also use it to program other decoders but it is pretty basic in this regard. Soundloader shines when it comes to modifying the Digitrax Sound decoders. It is very easy to use. You can choose from several sound projects available on the Digitax web site http://www.digitrax.com/sounddepot.php. I have several locos with Digitrax sound decoders installed. I placed a Kato AC4400 with and SDH104K1A on the track connected to the PR3. The programmer immediately recognized the Digitrax Sound decoder and was ready to program.

Lastly, I tried DecoderPro on the stand-alone programmer. This works equally well. The PR3 has the same programming ability as the Digitrax DCS100 in service mode programming. I was able to program all the conventional decoders just fine but had trouble with the SoundTraxx Tsunami just like with most DCC programmers. I hooked up my trusty DCC Specialties PowerPax to the PR3 . This did the trick. I could read and write to the Tsunami just fine. I have had several people ask me about this so I’m glade I finally got to try it.

I was not able to test the LocoNet Termination mode at this time, but I will assume that it works as advertised.

This is a very nice product and works very well. I would not hesitate to recommend it to anyone needing a PC interface for their Digitrax system. The fact that it is both an interface and a programmer is an added bonus.

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