DCC works by sending a sequence of serial data packets.
DCC system normally takes place from the command station to the power station (booster) to the decoders by means of the track.
The actual data transfer occurs by means of a current loop
NATIONAL MODEL RAILROAD ASSOCIATION (NMRA) DCC Standard
https://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-9.1_electrical_standards_2006.pdf
Decoder Programming
DCC Suppliers