DMX lines are made up of either 3- or 5-core shielded data cable terminated at either end with 3- or 5-way XLR type connectors (one male, one female). The DMX data itself requires only 3 of the cable cores, so more modern devices have started to use the 3-core alternative. In 5-core implementations, the two spare cores have no defined purpose (the Pearl 2000 desk from Avolites uses the extra cores as a second DMX512 output – using an appropriate splitter takes you from a single 5-way XLR to two 3-way XLR’s of DMX512). The wiring of the XLR connectors is shown below:
Where DMX is involved in a rig, it’s routing must be carefully planned out. As always, the cabling should be as discrete as possible, so running it along truss is desirable wherever and whenever possible. In order for the DMX to be transmitted to every piece of equipment that needs to receive it, a through-route needs to be determined for the DMX line starting at the console and ending with the furthest device from the console. Each device must be connected in a daisy-chain fashion.
This setup means that there are two certainties – firstly, no splitters or other such junction equipment are necessary and secondly, there is only ever one terminator. DMX lines can be run a maximum distance of approximately 1500 metres, and each line can support a maximum of 32 devices. Transmitting devices and DMX out ports on devices should be female connectors, while DMX in ports should be male connectors.