Digital Command Control (DCC) protocol decoding DCC (Digital Command Control) is a standard defined by the National Model Railroad Association (NMRA) DCC Working Group and is a standard for manufacturers to allow the independent control of multiple locomotives and accessories on a train set. This approach overcomes the limitation of controlling multiple locomotives on the same track where, traditionally, voltage on track was used to control the speed and direction of a train. The Digital Command Station sends DCC NMRA signals in a differential digital form, by periodically reversing the 15 V DC power supply to the track. PicoScope software can decode DCC command information being sent to DCC decoders. More information on Digital Command Control (DCC) protocol decoding >>