Then DCC mobile decoders in locomotives on the tracks use the DCC signal to power and control their locomotive’s speed, direction, and lights. “Stationary decoders” may also be connected to operate the track’s turnouts and other accessories. Basic DCC starter systems are all-in-one units. If you’re buying an all-in-one, make sure that it is expandable or can be integrated with the manufacturer’s other, modular components. The connection of DCC control system components has been left up to the individual manufacturers. Unfortunately, this means that throttles, command stations, and boosters from different manufacturers aren’t usually compatible. The DCC decoder has a power circuit that converts the DCC power signal into DC power for the motor and lights. The decoder also has digital logic which uses the power signal information to control the locomotive. Decoders are configured by setting configuration variables, or CVs. Today some decoders allow CV values to be programmed while the train is running on the main track. The one exception is that the CV values specifying the locomotive’s unique address cannot be changed while running. Addresses can only be changed on the programming track. Programming addresses can only be done when the locomotive is on a programming track. This is because the programming signal would change the addresses of all locomotives on your track if you didn’t isolate the locomotive you want to program on the programming track.
