Thanks Mark. The additional information (which I think you gave us before, but perhaps not as succinctly and clearly) helps. Rather than taking your locomotive apart, if you can run JMRI on a computer connected to your Zephyr (not sure if your version/generation of Zephyr has the built-in USB interface for a computer running JMRI or not), the Decoder Pro application within JMRI will read back a decoder and tell you the manufacturer and model of the decoder (assuming you have a programming track, since you are able to read some CVs back on the command station/throttle). Decoder Pro manages a database of your locomotives/decoders that you have either programmed or read out on the programming track. Each type of decoder has a dedicated series of screens with clear descriptions of registers/bits and their current (or last read out) contents. Using DP, you should be able to browse through your decoder's register definitions and contents (in English or your language of choice). Best of all, DP can read the entire decoder register contents and save them in DP's database, making it easy to restore your decoder to a previously saved state should things go awry during programming, experimentation, etc. I wouldn't dream of programming DCC decoders using anything but DP! jmri.org is the website for JMRI (note, JMRI is much more than just Decoder Pro; it handles many aspects of model railroading, including signals, routes, locomotives, railcars, running trains, etc. If you can imagine it, somebody has probably already put that model railroading feature or capability into JMRI, or they are working on it!
I am using DP with my DCC++EX and it has picked up the decoders in each of these locos. Unfortunately it highlights about a dozen different model numbers that I presume are similar, but in a case like this I don't have the experience to know if they are programmatically identical. I just chose one from each list and it seems to be working. Although I know the manufacturer, I don't actually know which specific decoder model is actually in there without taking off the shell and reading the printing. I also have a newer Zephyr and DP also worked well with that when I had a cheap laptop near the layout.
Decoder manufacturers share the same programming model (register layout, etc.) but have different form factors, power levels, connectors (or none), etc. to suit multiple applications across different locomotive models, scales, etc. This saves them a lot of development and manufacturing costs, and allows them to amortize some of those costs across multiple products with a larger total market. It is cheaper to reuse an existing decoder that has additional features for applications that do not use/need them, than to design and produce a dedicated decoder IC, and matching register map, for each variant. Likewise, JMRI DP uses the same programming model for these multiple decoders that share the same functional features (whether wired up or not.) That saves them development time. Remember, JMRI is developed and maintained by volunteers! Now, if you actually want to know whether independent ditch lights are implemented on a specific loco, you may have to 'lift the hood' and take a look. Ditto for whether the actual decoder is a shorting-plug replacement, a drop-in light-board replacement, or a hardwired version. Hope this helps...
