Multiplexer or “MUX” are devices whose function is to select one of several analog input signals and then forward the selected input to a single line output. Multiplexers are mainly used to increase the bandwidth of the signals over a network or connection, in short allowing multiple devices or sources to share the same input to another functional block. The opposite of the “MUX” is a “DEMUX” or demultiplexer which will take a single input signal and break it into multiple output signals. You will often find a “DEMUX” is on the receiving end of a “MUX”. Applications are varied for this type of device.