A DMX universe is a block of up to 512 control slots. A conventional physical DMX data link carries one universe; network protocols can transport many separately identified universes across a network.
512 slots does not mean 512 fixtures
A basic dimmer might use one slot, while a colour fixture, pixel system or moving light can require many. For an illustrative 16-slot mode, 32 fixtures fill 512 slots exactly. Other modes and patch gaps change the capacity.
Practical example
Four 100-slot fixtures can occupy one universe at starts 1, 101, 201 and 301. A fifth fits at 401, occupying 401–500; a sixth needs another universe or a different arrangement. These are example footprints, not the channel count of a particular model.
Network numbering
Document both the universe and start address when patching. Some Art-Net interfaces display numbering from zero and others from one; sACN numbering and user-facing labels must also match the system configuration. A universe number in software is not necessarily the number printed beside a physical output socket.
Equipment examples
The ARRI SkyPanel X supports different control arrangements. Consult the selected mode’s footprint before allocating space in each universe.
Related terms
DMX Address · DMX Personality · Art-Net · sACN
References
ETC: DMX glossary · ETC: output address and port/offset · Pathway: network universe numbering