is an analogue lighting communications protocol
used to control stage lighting
. It was developed by Strand Lighting in the late 70s and originally designed to handle 384 channels. Though more advanced protocols exist such as Digital MultipleX DMX
, it is still widely used in larger venues such as London's West End theatres, and popular amongst technicians because all the levels can be "seen" on an oscilloscope. D54 is still supported, and is available on the latest Strand 500 series consoles alongside DMX
One of the significant problems in controlling dimmers
is getting the control signal from a lighting control unit to the dimmer units. For many years this was achieved by providing a dedicated wire from the control unit to each dimmer (analogue control) where the voltage present on the wire was varied by the control unit to set the output level of the dimmer. In about 1976, to deal with the bulky cable requirements of analog control, Strand's R&D group in the UK developed an analogue multiplexing
control system designated D54 (D54 is the internal standards number, which became the accepted name). Originally developed for use on the Strand Galaxy (1980) and Strand Gemini (1984) control desks.
Although a claimed expansion capability of 768 dimmers was documented; early receivers used simple hardware counters that rolled over before reaching 768, effectively preventing commercial exploitation. The refresh period would also have been slow on... Read More