电信专业英英词典M-3（在线收听）

　　Multimode Optical Fiber(S)

　　Multimode fibers, with much wider cores than single mode fibers, allow light to enter at various angles, and reflect (bounce off of) core-clad boundaries as electromagnetic (light) wave propagates from transmitter to receiver. From a technical performance trade-off point of view, single mode fiber exhibits bandwidths of up to 100,000 MHz (MHz = 1,000,000 hertz or cycles per second = one megahertz) while multimode band width is in the range of 1,000 to 2,000 MHz (1,000 MHz = one billion hertz = one gigahertz = 1 GHz). See optical fiber(s); single modefiber(s).

　　Multiplexing

　　Multiplexing is a technique that enables a number of communications channels to be combined into a single broadband signal and transmitted over a single circuit. At the receiving terminal, demultiplexing of the broadband signal separates and recovers the original channels. Multiplexing makes more efficient use of transmission capacity to achieve a low per channel cost. Two basic multiplexing methods used in telecommunications systems, are frequency division multiplexing (FDM) and time division multiplexing (TDM).

　　Major Trading Area (MTA) - An area defined by the U.S. government and used by the Federal Communications Commission (FCC) to designate personal communications services market areas.

　　Mbps - Megabytes per second (MB is also used as an abbreviation for Megabyte).

　　Megabyte (MB)- A million bytes or a thousand kilobytes.

　　Miscellaneous Taxes - Like many other consumer goods and services, certain telephone services are taxed by federal, state, and local governments. These charges may appear as a ※gross receipts§ tax.

　　Modem - A device for converting digital signals from your computer into analog signals for transmission over a phone line (modulation) and also converts the analog signals from the phone into digital signals that your computer can read (demodulation).