A multiplexer, often abbreviated as MUX, is an electronic device that selects one of several input signals and forwards the chosen input to a single output line. It acts like a digital switch, allowing multiple data sources to share a single communication line, which helps in efficient data management and reduces the number of required connections. Multiplexers are commonly used in various applications, including telecommunications, data routing, and signal processing. They can be found in devices like television systems and computer networks, where they help in managing multiple signals without interference, ensuring smooth and organized data transmission.