Setting all of the various Digital Command Control (DCC) options in modern model locomotives can be a tedious and daunting task with most all hand-held DCC control units. Though it can be done on your main layout track ("Programming on the Main"), there are several limitations, especially if you usually run more than one locomotive on the same track at the same time. However, many DCC Sound decoders require a special programming mode, which may affect all DCC locomotives on the track! It is easier (and safer) if you remove all but the locomotive you are programming, to avoid accidental changes to all locomotives on the track. Also, other maintenance tasks (like wheel cleaning and testing) are much easier without the scenery getting in the way. For all these reasons, I decided to build a portable dedicated track board specifically for testing and programming DCC locomotives (and testing older DC-only locomotives).
With such a dedicated track, and an interface to a computer, I am able to run the Java Model Railroad Interface (JMRI) application, which makes it much easier to program DCC locomotive decoders! JMRI provides a more intuitive, full-screen descriptive interface for programming - no more bit-adding and hex conversions to configure through a small 2-line display and numeric keypad on your handheld controller. Combined with a dedicated program track, JMRI can automatically read all the configuration values set in a DCC decoder. And, I can build an inventory of configurations (roster) for all my DCC locomotives. This roster stores all the complex configurations on the PC, so if I ever need to reset my DCC locomotive's decoder to defaults (it happens occasionally), I can just restore the full configuration quickly from the JMRI application.
The photo above shows my completed programming track (for both On30/HO and N scale) at the bottom of the photo, and custom interface box on the left of the track. On the laptop's screen is the JMRI DecoderPro® application used to read and write "sheets" of related configuration values in structured plain English, rather than manually interpreting hex values into bit-maps of configuration settings.
I use the NCE Power Cab as my main DCC controller for my layouts. This versatile handheld unit (with cab panel) is the main layout power and control unit, providing both track power and controls for several locomotives at a time on the same layout track. It also provides the ability to program DCC locomotive decoders, both on the main track and on programming tracks. So, I can use the same controller from my layout, and simply unplug it and move it to my programming track for sophisticated interfacing with JMRI.
This overall diagram shows how the NCE Power Cab connects to my control box panel, and interfaces with a laptop via USB. I put all the necessary components inside a 4.7" x4.7" x3.5" (120x120x90 mm) project box. I mounted the box on the track board with velcro-like adhesive strips, so it can be easily removed and used to interface with any other track or layout, if needed. It doubles as a nice, portable NCE control box!
The two NCE control boards necessary are mounted inside the box. The Power Cab panel board is connected to the USB interface board with a short RJ12 6P6C flat data cable. Jacks and switches are mounted to the sides of the box for power and track control connection selections.
Note that the NCE Power Cab does not require (and should not use) any special DCC booster, as some DCC controllers require. It has its own program mode capable of programming most sound decoders (including Tsunami).
The NCE Power Cab is connected to the left-hand jack of the front panel (the Cab Bus panel jack is not normally used). These jacks are RJ12 6P6C data connectors standard for NCE cabs.
The USB Interface jack on the left side of the box is used to connect to the PC for the JMRI interface. The USB jack is a standard printer-type USB cable jack.
Both the On30/HO scale track, and the N scale track, are connected to the banana jacks (red and black) on the left side of this box view. These jacks are also handy for driving track accessories like locomotive wheel cleaners.
The "Track Control" select switch connects the tracks to either the NCE controller, or a separate DC controller connected to the jack below the switch. The DCC Power jack and switch is for the NCE power adapter that powers both the Power Cab panel and the USB interface.
In the following, links are just for reference. You can probably find many of the parts at your local model railroad hobby store, or hardware store.
NCE Power Cab - Controller & programmer for DCC (usually includes Connection Panel below)
NCE Power Cab Connection Panel - Control panel & jacks for control of the Power Cab, and connection to the USB Interface board.
NCE USB Interface Board - Connection and interface with PC via USB.
NCE P114, 13.8v DC Power Supply - If not already included with your NCE system.
Project Box - Plastic box to hold all the parts.
Power Connectors, 5.5x2.5 mm - Male and female barrel power connectors compatible with NCE power adapter. The 5.5mm x 2.5mm power connector is the size used by the official NCE P114 13.8 VDC power adapter.
Short RJ12 Data Cable, Straight Wiring - RJ12 6P6C data cable; make sure it is wired 1-2-3-4-5-6 pins to 1-2-3-4-5-6 pins (not a standard phone cable, which often swaps pins end-to-end!). Used to connect the NCE cab panel to the USB interface board, internally.
Panel-mount Socket & Plug - I used a 1/8" (3.5mm) mono panel-mount socket jack and plug, but really your choice for the connection to a DC Controller.
DPDT 6 Pin, 3 Position ON/Off/ON Toggle Switch - Best to use one with an "off" position between positions I & II to ensure a positive "break-before-make" position, but whatever you want. Used for the double-pole connection to the track, from DCC to DC.
On/Off Switch - Really, most any on-off switch should work. Used for the 13.8 VDC power supply.
Banana Plug Terminals - Again, many options would work - panel connections to the track.
5" x 54" Plywood - Base platform for mounting the track and control box. Your choice on size. I made my track about 42" to 44" overall.
Track Sections - I used Bachmann HO-scale E-Z Track sections (for HO & On30) since I already had some on hand. I used the Terminal Re-railers for connections to the box's track banana plugs. I added matching Hayes bumpers for the ends. For the N-scale track, I matched them with the Bachmann N scale track sections just for consistency. However, any track you need will work.