I’ve probably noted in the past that I’ll be using a couple of existing modules as a part of my new layout (once the basement is rebuilt). Those modules are built based on the Mid-Atlantic On30 Modules Spec, which I helped to develop.
This specification was developed over a two-year period and went through I-don’t-know-how-many iterations and variations, variously referred to as OCMods, OCUM and a probably a few others. Of the standard sets that came out of those often heated discussions, the Mid-Atlantic group specification has been adopted as the baseline standard for more On30 modular groups around the country than any other standard set.
It’s not a perfect standard, by any stretch of the imagination. But it is probably the best out there at present. It allows for a great deal of flexibility in module arrangement and lends itself to integration with other standards with relative ease, and with minimal compromise to its own design.
The electrical and DCC portions of the spec predate this module spec by about two years, and was one that I developed for the Four County Society of Model Engineers. It was specifically designed for use with NCE-brand DCC equipment, but also carefully designed to work equally well with Digitrax or Lenz systems. One item that the spec didn’t account for with NCE or Lenz systems was the need for a very large modular setup requiring more than a single booster (or set of centrally located boosters). While this was not a problem for Digitrax systems, which integrate the throttle bus and the booster bus on the Loconet cable, it requires that a second cable be strung out for remote boosters.
The bus as implemented in the spec calls for a six-conductor flat “Telco” cable or a Category 3 six-conductor network cable, terminated with 6-pin 6-contact RJ-12-style connectors. Loconet uses all six conductors, while NCE and Lenz only use four conductors for the throttle network (+12V, + Data, – Data and Ground). Further, NCE and Lenz use only two wires for the booster connections, making it theoretically possible to add the booster bus and throttle bus together on the same cable, and split them back out where needed. The drawing representing this will be developed some time in February, and will be posted to the Mid-Atlantic On30 Modules group on Yahoo!Groups and also uploaded to the On30Guy web site.