I am no command control expert by any means and maybe Barry Broskowitz can explain this to all of us.
How's this? From The DCS O Gauge Companion 2nd Edition, page 198:
Differences Between the DCS Remote Commander handheld and the DCS Remote
There are several important differences between the capabilities of the DCS Remote Commander Handheld and a DCS Remote:
• The DCS Remote can issue DCS commands to any PS2 engine that has been added to it. The DCS Remote Commander Handheld can only issue DCS commands to engines that have their DCS ID# set to what it was when it left the factory. For additional information regarding DCS ID#'s, refer to Appendix E: The Truth About DCS Engine ID Numbers, later in this book
• The DCS Remote can simultaneously operate multiple PS2 engines independently. The DCS Remote Commander Handheld cannot
• The DCS Remote communicates with the TIU via two-way radio frequency (RF) communication. The DCS Remote Commander Handheld communicates with the DCS Remote Commander Receiver using one-way infrared (IR) communications
• The DCS Remote can issue all DCS commands. The DCS Remote Commander Handheld can only issue a subset of DCS commands.
• The DCS Remote can operate switch tracks and accessories remotely via one or more AIUs. The DCS Remote Commander Handheld cannot operate switch tracks or accessories at all
• The DCS Remote has an LCD screen that displays information relating to the engine being operated and other items. The DCS Remote Commander Handheld does not have a screen
and from page 209:
Appendix E: The Truth About DCS Engine ID Numbers
First, it's necessary to dispel a myth: there is no PS2 engine ID# of 0. PS2 engines come from the factory with an internal ID# of 1 and a DCS Factory Reset changes the engine's ID# back to 1. The following explanation regarding the way in which DCS manipulates the engine ID# is provided for those readers who are interested in how DCS works, as might be said, under the hood. The DCS engine numbering scheme works in the following way.
DCS always places an ID# in a PS2 engine that is one greater than the ID# that it displays for the engine in the DCS Remote, i.e., if one adds a PS2 engine to a DCS Remote and the engine adds as ID# 11, the number written into the PS2 engine's memory is actually 12. This causes DCS ID#s that display in the remote from 1-99 to
actually be resident in PS2 engines as 2-100. That's also why DCS ID# 99 is a special case - it's actually in the engine as 100, the only 3-digit internal PS2 engine ID# number.
Further, this also explains why one cannot place a new PS2 engine, or one that has just been Factory Reset, on the track and run it under DCS using an entry in the DCS Remote for engine number 1. In this case, the DCS Remote is looking for an engine that has an internal ID# of 2.
This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!