DMX stands for Digital MultipleX, which stands for Multi Channel Digital Transmission.
The DMX512 control protocol is an industrial standard for data transmission between lighting controllers and lighting equipment, published by the American Stage Lighting Association (USITT) in 1990.
Its full name is USITT DMX512 (1990), which includes electrical characteristics, data protocols, data formats, and other aspects.

Working principle of DMX512

The data transmission is based on an 8-bit asynchronous serial protocol with a start bit (low level) and two stop bits (high level), without parity check.
Therefore, a data frame has 11 bits Due to the width of each bit being 4us, it takes 44us to send a frame.
 If the line wants to send a continuous data stream, it will generate a baud rate of 250000 b/s, also known as 250 kbps. An 8-bit word allows each dimmer to send
 256 independent levels in the range of 0 to 255. (The following figure shows the wiring diagram of the Oches DMX512 series products)