Multiplexers (MUX or MPX) are network components used to combine several physical or logical channels on a single transmission medium or transmission channel. Multiplexing techniques are based on the reservation of partial transmissions in terms of time, space, code or frequency. These transmission techniques make multiple use of the transmission lines or the radio link.
In accordance with the technical approaches, in time-based multiplexing the various transmission channels are switched onto the transmission line one after the other in time. Depending on the multiplexing method, each channel can be provided with equal or different time ranges.
Such time division multiplexing can be synchronous or statistical. Space multiplexers, on the other hand, use several transmission media over which several transmission channels can be transmitted in parallel. In code division multiplexing, signals are encoded with individual code sequences. And as far as frequency multiplexers are concerned, these components multiplex the channels to different transmission frequencies. The same applies to wavelength division multiplexing, which is used in optical networks.