(mux, dmx512, d54, protocol) All modern lighting desks use this serial form of communication with dimmers. All the information from the desk is transmitted along a single pair of cables to the dimmer where a de-multiplexing unit (demux box) decodes the string of data and passes the correct piece of information to the correct dimmer. The inductry standard protocal (language/standard) for multiplexing is the digital USITT DMX512. However, new protocols are continually being added to keep up with more demanding equipment. SMX is a communications protocol which enables digital dimmers to "report back" to the desk on any faults (eg blown lamps). D54 uses a stream of analogue voltage levels and was the Strand standard before DMX512 arrived.