A multiplexer makes it possible for several input signals to share one device or resource, for example, one analog-to-digital converter or one communications transmission medium, instead of having one device per input signal.
How Does a Multiplexer Work? In this figure, the switch has four inputs with one output pin and you can select based on the signal given. It demonstrates the three basic parts of any multiplexer namely the input pins, output pins, and control signals.
The word "switchplexer" is a portmanteau of "switch" and "multiplexer". It is sometimes used to describe a combination of switches and filters, often associated with multi-band operation in cell phones.