 although only one may transmit at a time. multimedia The presentation of more than one medium-typically images, sound, and text-in an interactive environment. multimode fiber A fiber-optic cable with a core diameter large enough to allow light to travel on different paths, supporting propagation to multiple nodes. multipath A propagation phenomenon that results in radio signals' reaching the receiving antenna by two or more paths. Multipath affects the quality of communication because it can create secondary and tertiary signals that compete or interfere with the primary signal. multiple-access technique A method that enables sharing of spectrum by multiple users. FDMA, TDMA, and CDMA are examples of multiple-access techniques. multiple trunk groups Groups that indicate that the switching system is capable of being equipped for more than one group of trunk circuits. multiplex To interleave or simultaneously transmit two or more messages on a single channel. multiplexer A device that enables more than one signal to be sent simultaneously over one physical channel. A multiplexer, sometimes called a mux, combines inputs from two or more ter- minals, computer ports, or other muxes and transmits the combined data stream over a single high-speed channel. At the receiving end, the high-speed channel is demultiplexed, either by another mux or by software. Glossary multipoint multipoint Pertaining or referring to a communications line to which three or more stations are connected. Multipoint implies that the line physically extends from one station to another until all are connected. multipoint network In data communications, a configuration in which more than two ter- minal installations are connected to a single port. multiprocessing The simultaneous execution of two or more computer programs. See multiplexer. MVNO (mobile virtual network operator) Companies that do not own licensed spec- trum of their own but instead make use of another mobile operator's network, while reselling the wireless services under their own b