Correct ERR Components

The Dummy Loco board will control headlight, backup light, front and rear electrocouplers and also has a serial data output for a sound board.  Thus it will work with a RS Commander to provide sound in a dummy unit.  Instructions may be lacking, however.  When I got mine (several months ago, bought a couple since they're cheap), they included a 1-page wiring diagram labeled "RCDR."  Since I've done lots of TMCC installations, that was enough for me but it doesn't really tell how exactly to connect the RailSounds board if you have no experience with one.

They may have a more extensive installation manual now, I don't know.  There is no link to an RCDR manual on the ERR site.

The dummy Loco Board is the way to go.  The late Boxcar told me the commander EX did not work with the ERR sound boards.  I have dummy loco boards with ERR sound boards and they work.  Also you can have couples and LED lights.  search ERR Dummy Loco Board here on the forum for help.

Again, ERR really needs to dial-in their descriptions, product application guide and installation instructions for the average 3-railer. They are missing the boat in my opinion.

Keith is correct, the MC-EX doesn't properly handle the serial data out to the sound board.  I use the dummy loco board.  As noted, there are no real instructions, other than the single page, for the dummy loco board.