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Telecom Dictionary - M

Ma Bell - This older term refers to the old AT&T and Bell Systems.

Macro - This usually refers to a series of instructions or text that can be entered by hitting a key or combination of keys.

Machine Language - This is a computer language that are commands that can be carried out by a piece of computer hardware without any further compilation.

Magnetic Disk - Magnetic-coated disks that record data bits (used for data storage).

Mailer Daemon - A computer program that tells you why your email message could not be delivered.

Mainframe - A large computer to be used in a multipurpose environment. It is usually linked to many peripherals.

Mains - Another name for a normal power outlet (this term is used in foreign countries).

Majordomo - This is email processing software.

Make Busy - To intentionally take the phone of the hook.

Manual Telephone - A.k.a. a courtesy phone. This phone dials a predetermined number immediately upon pick-up.

Margin - A satellite system requires certain minimum signal levels for operation. The amount that the the signal is over that minimum level is the margin.

Mark - This (1) means to flag a record, or (2) it is a coding term that indicates the binary digit "1", as opposed to "0" being represented by a space.

Markup - These are special codes that describe how parts of a document are to be processed by a particular software application.

Master - The piece of equipment that supplies the transmission's timing signal.

Master Antenna Television (MATV) - Where there are a concentration of televisions, such as in hotels or apartment buildings, a single master antenna system may supply all of them.

Matrix - This terms means (1) a switch, or (2) the surrounding material in a composite.

MATV - see Master Antenna Television.

MB - see Megabyte.

Mbps - This is a million bits per second (a measurement of data transmission rate).

MBps - This is a million bytes per second.

Mean - Another term for the arithmetic average.

Media - The conduit or link that is used to carry the transmissions (i.e., a newspaper or electromagnetic television wave).

Medium Earth Orbit (MEO) - A particular orbit that is in an altitude that is approximately halfway between the Earth and the geosynchronous orbit. These orbits typically fall in the range of altitudes of 9,000 - 15,000 kilometers (km).

Megabyte (MB) - 2 bytes raised to the 20th power (i.e., 1,048,576 bytes).

Megahertz (MHz) - A frequency that is equal to 1,000,000 Hertz (cycles per second).

Memory - The part of the computer or other device that stores information.

Menu - A list of options from which you can choose.

MEO - see Medium Earth Orbit.

Message - A collection of symbols or characters used to convey information.

Meta Tag - This is an optional HTML tag (such as the <title> tag) used to provide information to web crawlers (which are programs) about the particular webpage that the meta tag is on.

Metric - This is not the metric system, but rather a measurement or particular benchmark.

MHz - see Megahertz.

Microprocessor - This is a circuit on a chip that can perform, with internal memory capability, control, logic, and arithmetic functions.

Microsoft - One of the largest software companies in the world. We're sure we don't need to say much more than that.

Microwaves - These are point-to-point transmissions of electromagnetic signals at high frequencies (between 890 MHz and 20 GHz). They can be used for all types of information transmission, but with the advent of fiber-optic technology the use of microwave relays has lessened.

Microwave Interference - When an earth station receiver picks up signals from earth-based telephone microwave relay transmitters, radar transmitters or the even the sun, interference in the sought-after satellite signal can occur. Sometimes adjusting the placement of the satellite dish or other antenna will reduce the interference.

MIPS - This means Millions of Instructions Per Second.

Minitel - An older French public network.

MIS - This stands for Management Information Systems, and is really just another name for data processing.

Modem - This is an shortened term for MOdulator/DEModulator, and is a computer peripheral which allows computers to communicate over telephone lines.

Modulate - To vary the carrier wave in some way to transmit information over that carrier wave.

Modulation - This term typically refers to AM (amplitude modulation) or FM (frequency modulation). It is the manipulation of the amplitude (in AM) or frequency (in FM) of a carrier wave in a way that corresponds to the data, video, or voice signal.

Modulator - This is a device with the purpose of modulating a carrier wave and are basic components in both satellite transponders and broadcasting transmitters. Home video cassette recorders (VCRs) have modulators in them so the video recorded on the tape can be played back and viewed with a television set.

Morse Code - A binary language that is a series of dashes and dots and is used for telegraph communications.

Motherboard - This is the main circuit board of a computer system.

MP3 - This stands for MPEG Layer-3, and it is the most popular audio compression format on the internet.

MPEG - This stands for Moving Pictures Experts Group, which is the television industry's informal standards group.

MPEG-2 - This is the standard for the data compression (both coding and encoding) for digital television.

MPEG-2 MP@HL - This stands for Main Profile at High Level, and is a higher bit-rate system that has been implemented to carry HDTV (high definition TV) in a widescreen system.

MSN - The Microsoft Network.

Multicast - If broadcast transmissions go to all the viewers in a region (or set), then multicast includes transmissions that are sent to a defined subset within the entire set of viewers. See Unicast.

Multiplexing - These are methods that allow multiple, simultaneous transmissions over one single circuit.

Mute - A telephone feature that prohibits voice from being transmitted from the side of the conversation that initiated the mute.

M/W - This stands for microwave.

MXR - A multiplexer.