In the field of modern communication and data processing, the multiplexer (MUX), as a critical device, plays an irreplaceable role. It selectively combines multiple input signals into a single output signal, thereby achieving efficient utilization of communication channels and reducing system costs. This article will provide a detailed introduction to the definition, principles, functions, and applications of multiplexers across various domains.

RS485 (Recommended Standard 485) is a serial communication standard developed by the Electronic Industries Association (EIA) in 1983. It defines an electrical characteristic of differential signal transmission, supports multi-point communication and long-distance data transmission, and is one of the most commonly used serial communication interfaces in industrial environments.