<P> In wired communication, space - division multiplexing, also known as Space - division multiple access is the use of separate point - to - point electrical conductors for each transmitted channel . Examples include an analogue stereo audio cable, with one pair of wires for the left channel and another for the right channel, and a multi-pair telephone cable, a switched star network such as a telephone access network, a switched Ethernet network, and a mesh network . </P> <P> In wireless communication, space - division multiplexing is achieved with multiple antenna elements forming a phased array antenna . Examples are multiple - input and multiple - output (MIMO), single - input and multiple - output (SIMO) and multiple - input and single - output (MISO) multiplexing . An IEEE 802.11 g wireless router with k antennas makes it in principle possible to communicate with k multiplexed channels, each with a peak bit rate of 54 Mbit / s, thus increasing the total peak bit rate by the factor k . Different antennas would give different multi-path propagation (echo) signatures, making it possible for digital signal processing techniques to separate different signals from each other . These techniques may also be utilized for space diversity (improved robustness to fading) or beamforming (improved selectivity) rather than multiplexing . </P> <P> Frequency - division multiplexing (FDM) is inherently an analog technology . FDM achieves the combining of several signals into one medium by sending signals in several distinct frequency ranges over a single medium . In FDM the signals are electrical signals . One of the most common applications for FDM is traditional radio and television broadcasting from terrestrial, mobile or satellite stations, or cable television . Only one cable reaches a customer's residential area, but the service provider can send multiple television channels or signals simultaneously over that cable to all subscribers without interference . Receivers must tune to the appropriate frequency (channel) to access the desired signal . </P> <P> A variant technology, called wavelength - division multiplexing (WDM) is used in optical communications . </P>

How would it multiplex phone calls onto a single wire