DMX works by daisy-chaining DMX-compatible devices along a single 3- or 5-conductor wire. Beginning with the DMX controller, which manually or automatically turns lights and functions on or off, each light or device along the wire is assigned a binary digital address for the controller to recognize. Up to 512 channels can be used with a single system, which is why DMX protocol is often referred to as "DMX512."
A DMX device is any fixture that can be controlled by a DMX controller, and is able to be assigned a DMX address (usually with movable, numbered switches). DMX devices include DMX "Intelligent" lights, DMX dimmer or power packs, and DMX controllers.
DMX intelligent lights come in many forms, including lights that can be programmed to move, change color, or change patterns. Lasers, strobe lights, robotic spot lights, and image projectors are considered intelligent lights, with functions controlled by the DMX controller.
DMX can control any type of lighting or electrical fixture, but non-DMX fixtures must first be connected to the signal chain via DMX power or dimmer packs. Power packs allow lights to turn off and on, and dimmer packs allow lights to be dimmed at levels set at the DMX controller.
The benefits of using DMX are numerous. Although lighting fixtures must be connected to standard electrical service, the DMX control system itself uses very low voltage along the daisy-chained control wire. DMX systems are easily expandable, and only require additional fixtures and wires to add to the system. Since DMX is digitally controlled, large light shows can be fully programmed and run by computer using DMX software.
DMX protocol is safe for DMX approved stage lighting use, but has limited safety features for potentially dangerous stage effects. Since any electrical appliance or device may be connected to a DMX system, pyrotechnics, mechanical devices, or other effects that require fail-safe controls, should never be used with DMX.