Schematic symbol of a 2-to-1 Multiplexer. It can be equated to a controlled switch.
Schematic symbol of a 1-to-2 Demultiplexer. Like a multiplexer, it can be equated to a controlled switch.
In electronics, a multiplexer or mux (occasionally the term mul-dex is also found, for a combination multiplexer-demultiplexer) is a device that selects one of many analog or digital input signals and outputs it into a single output line. This process is termed: multiplexing.
An electronic multiplexer makes it possible for several signals to share one expensive device or other resource, for example one A/D converter or one communication line, instead of having one device per input signal.