DMX512-A

A Universe contains 512 addresses and a single DMX line (cable) can only transmit one universe. I.e. a controller with two universes need two DMX lines (daisy chains including splitters). A uniververse is normally thought of as an address space (in the controller), the cables that transmits it and the equipment that receives it.

• The DMX signal is made up of a sequence which is sent over and over again (to increase robustness).
• The content is a "start byte" and 512 values, one value for every address.
• The address number is not sent over the lines, so the receiver must count the values from the start of the sequence to find the wanted value.
• A receiver must be set or programmed to an address it listens to. If a receiver listens to multiple addresses, the set one is the first.
• Multiple receiver can listen to the same address - the DMX system does not care.
• It is up to the controller/transmitter to decide how many addresses that should receive a value. Fever addresses means faster cycles.

Source: Wikipedia