Many years ago theaters and concert halls used analogue control systems that ranged from 0 – 10V. These analogue control signals came from a massive lighting desk and had to be distributed through thick, multicore cables to the compatible dimmers that were able to interpret the control voltage.
The effort of cabling was enormous as every dimmer channel had to have its own control signal. It took a lot of time to get that running on a touring event.
During the mid-80’s more and more intelligent lighting fixtures were introduced onto the market and Scanner and Moving Heads became a thing. Actually it was the British band Genesis that invested into the first automated lights from Vari-lite. These intelligent fixtures required more control channels than just a dimmer. They featured position, colors, gobos, focus and many more. Thus raising the count of analog control signals into an inconvenient level.
To resolve this issue, Digital MultipleX-Signal (DMX) was introduced by the USITT (United States Institute for Theatre Technology) in 1990. From now on it was possible to transmit up to 512 independent channels (Universe) through a single DMX cable. Each channel with a digital value of 8 bit (256 steps) and a refresh rate of up to 44 Hz.