Lighting data has moved from one long DMX line to Ethernet networks carrying dozens of universes. The principles are simple, but the details decide whether a rig is rock-solid or flickers at the worst moment. This guide covers DMX512 basics, when to move to Art-Net or sACN, and the hardware that makes it reliable.
DMX512 rules that still apply
- Use real DMX cable. 110-ohm, low-capacitance cable with 5-pin XLR (3-pin on many DJ fixtures). Microphone cable “works” until it doesn’t.
- Terminate the end of every line with a 120-ohm terminator, and keep a line to a practical 32 devices and a few hundred metres.
- Split, don’t daisy-chain forever. An optically isolated DMX splitter per truss or rack contains faults and lets you run shorter, cleaner lines. Luminex LumiSplit, ChamSys GeNetix, Lightronics IDW and Chauvet RDMX splitters are RDM-aware.
- RDM lets the console address, identify and monitor fixtures over the same cable. Buy RDM-capable splitters and nodes so you can use it.
Art-Net vs sACN
Both protocols carry DMX universes over Ethernet. sACN (E1.31) uses multicast and per-source priorities, which makes merging consoles and backups elegant, and is the standard in theatre and installation. Art-Net is widely supported in fixtures, media servers and visualisers and is simple to set up. Most consoles output both; many rigs use sACN for fixtures and Art-Net for media. Whichever you pick, the console’s universe limits and the node’s port count define capacity.
Nodes close to the fixtures
The idea is to run Ethernet — not DMX — over distance, then convert to DMX at the truss with a node. Portable nodes such as Luminex LumiNode, Obsidian NETRON and ETC Response Mk2 gateways output 1 to 8 universes each; installation gateways and DIN-rail nodes serve wall boxes and racks. Processing units (grandMA3 PU, MagicQ Stadium Connect) expand console parameters rather than just converting protocols.
Switches built for shows
A consumer switch can pass sACN, but a show network needs managed switches that handle multicast properly (IGMP snooping and a querier), keep lighting, audio and video on separate VLANs, provide PoE for nodes and wall stations, and tolerate road use. Luminex GigaCore switches with etherCON and opticalCON connectors and Obsidian NETRON PoE switches are built for exactly this; NETGEAR managed switches are a sensible option for fixed installs on a budget.
Cable and connectors
Shielded CAT5e or CAT6 with etherCON connectors survives touring; fibre with opticalCON covers long runs and electrically noisy environments. For installs, LSZH jackets and plenum ratings may be required. Keep DMX and network cable away from dimmed power and feeder, and label everything.
Redundancy and testing
Design so that one failure is survivable: dual-homed consoles, a backup processor, redundant ring topology on switches that support it, and spare nodes in the rack. Carry a DMX/RDM tester such as the City Theatrical DMXcat to confirm data at any point in minutes.
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