Every DMX-controlled device must be assigned a unique start address within its universe. Addressing is the process of mapping control channels to physical devices during system setup—one of the most fundamental tasks an entertainment electrician performs on every installation and touring show.

The DMX Universe

Per ANSI E1.11 (DMX512-A), a single DMX universe contains 512 slots (channels), numbered 1 through 512. Each device occupies one or more consecutive channels beginning at its start address. The number of channels a device uses is determined by its operating mode or personality. A critical rule: no two active devices on the same universe may share the same channel, or erratic control will result.

Address Assignment Methods

DIP Switch Addressing

Legacy and many budget fixtures use an 8- or 9-position DIP switch block to set the start address in binary. An 8-bit DIP switch provides addresses 0–255; a 9-bit block provides 0–511 (mapped to DMX addresses 1–512 with an offset). Switch position 1 = value 1, position 2 = value 2, position 3 = value 4, and so on (powers of 2). To address a fixture at channel 65: 64 + 1 = DIP switches 7 and 1 ON.

Digital Menu Addressing

Modern fixtures use on-board LCD menus to set the start address numerically. This eliminates binary conversion errors and allows access to personality/mode selection in the same menu system. Some fixtures also support RDM-based soft addressing from the console.

RDM Remote Addressing

RDM-capable fixtures can be discovered and addressed wirelessly from a compatible controller without physically touching each unit—invaluable for fixtures in difficult overhead positions. The process: initiate discovery, select fixture by UID or location label, assign start address, confirm.

Dimmer Addressing

Dimmer modules in a rack are typically factory-addressed in sequential order. A 96-circuit rack might occupy channels 1–96 on universe 1. The console’s soft patch maps console channels to DMX channels, allowing flexible renumbering without rewiring. The rack’s physical patch panel may offer a one-to-one or custom patch independent of the console.

Scroller Addressing

A color scroller clips a continuous scroll of gel in front of a fixture and uses a single DMX channel to position the gel at any of 16–32 frames. The DMX value (0–255) is divided proportionally across the number of frames. The scroller address is typically set adjacent to the dimmer channel it serves, though the two are independent DMX signals.

Moving Light Addressing and Personality Modes

Moving lights are the most complex addressing scenario. A fixture’s mode or personality determines the number and function of DMX channels it uses:

Address spacing formula: The start address of the next fixture equals the start address of the current fixture plus the number of channels it uses.

Example: Fixtures using 20 channels each, starting at address 1: Fixture 1 = 1, Fixture 2 = 21, Fixture 3 = 41, Fixture 4 = 61 …

A universe of 512 channels can hold: 512 ÷ 20 = 25 fixtures (with 12 unused channels at the end).

Address Documentation

Proper address documentation prevents troubleshooting nightmares during load-in:

• Patch sheets: Spreadsheets listing fixture number, circuit/dimmer, DMX address/universe, console channel, and fixture type
• Instrument schedule: Master list of every fixture with its position, type, color, and control address
• In-console patch: The definitive record; export and save with each show file backup
• Physical labels: Address labels on each fixture’s DMX connector or body for quick identification during focus

References

ANSI E1.11. (2008). Entertainment technology: USITT DMX512-A — asynchronous serial digital data transmission standard for the control of lighting equipment and accessories. ESTA/PLASA.

ANSI E1.20. (2010). Entertainment technology: RDM — remote device management over DMX512 networks. ESTA/PLASA.

ANSI E1.31. (2018). Entertainment technology: Lightweight streaming protocol for transport of DMX512 using ACN (sACN). ESTA/PLASA.

Entertainment Technician Certification Program. (2023). Entertainment electrician examination content outline. ESTA.

Entertainment Services and Technology Association. (2023). Entertainment technology standards. ESTA/PLASA.