Lou, my response is based on a discussion that started on 2-2-17 "Lionel Railsonds history" it is worth a search and read. This is a quote from that discussion by GGG in response to a post by Mike Reagan.
"Wasn't part of this that RS up through and including RS 2.0 were conventional only? RS2.5 was the first TMCC based RS and that was in the early NYC/SP GP-9?
Also RS 3.0 board does require the early LARGE power Supply board. After RS 3.0, the powerboard became universal and smaller. Even works with modular Legacy.I have moved RS 2.0 chips into RS 2.5 platforms and they work in TMCC mode. But the 2.0Hardware is not command capable. G"
The RS2 boards were the first to use removable programmable PIC and ROM chips. The chips in the RS2 board could be transplanted into the RS2.5 board and give full TMCC capability. However the RS2 boards do not talk to TMCC. j
