BTW: The link provided by Len works on my Browser (Firefox 53.0 (32-bit) on Win10 64bit)  (guess I need to install the 64bit version of Firefox!)

Well, doesn't that make me feel like a dope! 

I did find that set of documents, and I read S9.2 ("Communications Standards For Digital Command Control"), but assumed that any "Extended" format(s) would all be propitiatory (i.e. that the Extended specification was merely a way for manufactures to come up with their own DCC commands). 

So, sorry for making A$$e$ out of all of you -- I certainly feel like one 

Hi, I want to use an Arduino to automate my HO trains (and, maybe even, ultimately, a Raspberry PI/Arduino arrangement that would allow me to also create a Website with an interactive interface).  I haven't found a Bachmann DCC controller that is "Open Source" enough for me to do this (at least not one that is within my price range).  I'm an Electrical Engineer and have already programmed an Arduino to produce basic DCC packets. I've also designed a booster.  I did this all in anticipation of the arrival of my new Bachmann "HO ALCO 2-6-0 Steam Locomotive" with "DCC Sound Value On Board" (my first of hopefully several).  I was hoping a DDC command specification would be included, but instead, all I can find are "CV" designations.  Is there a way to relate these CV values to actual DCC packet fields?