DCC Service Mode Tips

4 different official modes:

address mode - outdated, only updates CV1. For really old stuff, and if this mode is attempted on a newer decoder, it's possible that it does not update CV19 and/or CV29. Think original LGB stuff.

(physical) register mode - old stuff again, and old decoders had registers that corresponded to cvs 1,2,3,4,7,8,29. No long address support

page mode - extension of register mode. Uses register 6 as an index, and using 4 other register values, yielded 1024 cvs effectively... Often this has to be used for old decoders, or really dumb ones like switch machine controllers, or old weird stuff from europe

direct mode - what is mostly used today... the standard states 1024 cvs