Hi Ted,
I see nobody has responded to you.
In fact as yet their is NO NMRAnet standard. One was proposed by a group in the US north-west but was withdrawn as it had never been put to the working group. An attempt was made by the working group to put forward a physical layer proposal, which can be seen
here, but which ended up being modified by internal NMRA people and was never approved by the board and has now been at least temporarily withdrawn.
Currently the situation is really murky. Didrik Voss, the Standards and Compliance Manager for the NMRA has closed down the working group Yahoo list. He is not responding to queries or emails. Because the NMRA, in the person of Di Voss, created a derivative work based on that created and copyrighted by members of the working group their is now an ugly copyright situation.
The members of
OpenLCB have been the prime movers behind the NMRAnet effort with contributions from some manufacturers and other interested parties. But the NMRA process seems to be broken right now. At present we are in contact with the NMRA board of directors through individual members, their legal counsel and some of the elected officers. We have been invited to make a presentation to the board in July in Sacramento, California, at the National Convention.
OpenLCB as a distinct effort only arouse out of the breakdown of the NMRAnet process itself back in 2008 and has always been focussed on moving forward with a comprehensive and viable standard. In July 2010 in Milwaukee we felt that NMRAnet could once again move forward as an NMRA sponsored process, but in the run-up to the mid-term board meeting in February 2011 the process once again broke down. I think I can speak for my colleagues at the core of the OpenLCB project when I say that we hope that NMRAnet can once again move forward in the near future.
In the meantime, their are currently two aspirants for standardization as
NMRAnet,
OpenLCB which is called S9.6 on the NMRAnet site and
CBUS. Another group, S9.5 is mentioned on the website also, but they have not taken the opportunity to update their material or include full protocol specs in some time.
I know this muddies the water a little, but I hope you might look at OpenLCB and see if it fulfills your needs. There is a Yahoo group ( OpenLCB ) where you will find a number of software and hardware developers as well as the core protocol developers.
Kindly, John