@CurtisH posted:DCS is MTH Digital Command System and is used for OGauge 3 rail. DCC is Digital Command Control and is used mostly in HO and N gauges. DCC is set by CV's. (with me having a terrible memory it is hard for me to use). CV is Control Variable. Here is the NMRA Definition - https://www.nmra.org/beginners...mand-control-and-dcc.
In addition, the NMRA established standards for DCC, so "most" engines will work on any manufacturer's control system. In the 3-rail world we have a mish-mash of systems. Oh, and DCC equipment is readily available; TMCC/Legacy and DCS not so much. Not that I'm bitter or resentful...