M: m-MZI

m-Maintenance Hole

m

1. (small letter) Milli. One-thousandth. M (big letter) Mega. One million, e.g. Mbps or Mbit/s, one million bits per second. But m or M is confusing. There are some places it will mean a thousand and other places it will mean a million. You need to check the context and often ask. My brokerage statement, for example, uses a big letter M to mean thousand. In short, be careful.

2. Meter. The fundamental metric unit of length, a meter is equivalent to 39.37 inches. See Meter for more detail.

M Bit

The More Data mark in an X.25 packet that allows the DTE or DCE to indicate a sequence of more than one packet.

M Hop

The transmission of satellite signals through an uplink to a satellite that downlinks to a receiving station half-way or between the final receiving station. The intermediate receiving station uplinks the signal again to a satellite for delivery to the final, targeted receiving station. As an example, data from a company in the UK for a business in Japan may be sent to a satellite covering North America and Europe. The signal is downlinked to an earth station in Colorado. The signal is then uplinked to a satellite covering Asia and North America for final delivery to an earth station in Japan. The signal flow forms an 'M', thus the name .

M Patch Bay

A patching facility designed for patching and monitoring of digital data circuits at rates from 1 Mbps to 3 Mbps.

M Port

The port in an FDDI topology which connects a concentrator to a single attachment station, dual attachment station, or implemented in a concentrator. This port is only implemented in a concentrator.

M VTS

Marconi Video Telephone Standard sends color pictures over regular phone lines at up to 10 frames per second at 14.4 Kbps. The MCI Video Phone, which conforms to this standard, has a resolution of 128 by 96 pixels.

M&C

Monitor and Control.

M-ES

Mobile End System.

M/W

Microwave.

M.100

M.100, a specific API for S.100 Server Configuration and Control, now available from the Enterprise Computer Telephony Forum (ECTF). By managing the configuration, startup and shutdown of S.100-conforming computer telephony servers, M.100 allows Call Centers to provide more consistent service through better-configured, more stable servers and orderly shutdown when problems occur. In its July issue, Computer Telephony Magazine said M.100 "addresses

1. configuration management,

2. performance management,

3. statistic management and

4. fault management across the system/server and application level.

M.100 was announced on April 22, 1998. At that time, the ECTF said M.100 allows users to ensure that all of the resources and other elements of a server are brought up in an orderly manner during startup to produce a stable environment. If problems occur during operation, M.100 allows the server to be shut down without loss of data, a critically important benefit to large Call Centers. During a shutdown, M.100 allows all current calls to be handled and prevents additional calls to be taken or created until shutdown has been completed. This enables Call Centers to continue servicing customers without catastrophic interruptions even when problems occur. M.100 employs session and event management, symbols and data types from S.100, and it defines functions that allow administrators and developers to create customized administration applications. These include management of configuration data, management of services, startup and shutdown, information about service providers and handling of generic administration commands. M.100 also contains the infrastructure hooks that enable inclusion of vendor-supplied diagnostic tools. This feature allows users to easily configure a system with those diagnostic routines needed to create a highly stable environment. Because M.100 is a specific API for S.100 servers, it addresses several key areas not covered by the network management APIs. First, the startup and shutdown of an S.100 server is specific to its operating system environment. If the server were running under Windows NT, it would be started as an NT service, and M.100 would control the startup and the shutdown of the various services. M.100 also supports making persistent information available on the server that can be accessed whenever new applications or services are installed or removed. This data is referred to as a profile that is similar to an INI file. An S.100 server contains multiple profiles that describe all the components that make up the server. M.100 allows for manipulation of the profiles making for much cleaner server configurations and re-configurations. Also, M.100 makes it much easier to handle KVSets, the preferred mechanism for using data within an S.100 server. M.100 is available from the ECTF Web Site at www.ectf.org.

M.500

A set of Management Information Base (MIB) objects for use in managing CT servers and resources through SNMP. The ECTF which fathered the M.500 calls it a Management Information Base (MIB) Interoperability Agreement that specifies the standardized administration of Computer Telephony (CT) servers. M.500 allows developers of CT solutions to demonstrate a more complete solution to their customers by including practical visibility into their products. This comprehensive management capability, according to the ECTF, allows users to deploy a rich set of mixed media applications using off-the-shelf hardware and component software. It also allows them to fine-tune performance and get the most out of the advanced technology inherent in today's CT solutions. The standards- based management offered by M.500 provides a very practical way for users to realize a long- term reduction in cost of ownership by providing greater interoperability options with new CT components that extend the life of the overall system. M.500 contains object specifications for both CT server vendors and resource providers. Vendors support the portion of the MIB relevant to their offering, and the user is then able to view and manage the entire CT server as a whole. Additionally, M.500 is leading the industry by releasing the first MIB for fax resources.

By using the new M.500 MIB, IT managers can confirm whether or not important resources, such as fax server ports, are active. They can also monitor fax call statistics, such as the number of fax calls placed and connection attempts and failures for a specific fax destination. Data of this type, according to the ECTF, can help IT managers make full use of available fax resources and allow them to make adjustments to imbalances between business requirements and the supporting fax resources. According to the ECTF, M.500 follows the same industry standards as the other industry MIBs that manage hubs, bridges, routers, etc. It can be implemented using Simple Network Management Protocol (SNMP) allowing customers to use off-the-shelf tools, such as HP OpenView (TM) or IBM NetView (TM), to manage their CT systems. M.500 is fully extensible allowing the addition of objects to manage unique aspects of a particular product. M.500 is available for downloading at the ECTF Web Site at www.ectf.org.

M1

1. Multiplexer in the U.S. digital signal hierarchy. See M1, which is listed as if it were M-ONE in this dictionary.

2. Management Interface 1: The management of ATM end devices.

M2

Management Interface 2: The management of Private ATM networks or switches.

M3

Management Interface 3: The management of links between public and private networks.

M4

Management Interface 4: The management of public ATM networks.

M5

Management Interface 5: The management of links between two public networks.

M12

Multiplex 1-to-2. A designation for a multiplexer which takes four DS-1 (T-1) signal inputs at 1.544 Mbps and interleaves them into a single DS-2 (T-2) output at 6.312 Mbps, adding additional signaling and control bits. See also M13, Multiplex , T-1, and T-2.

M13

Multiplex 1-to-3. In the U.S. digital hierarchy, multiplexers are called by the digital signal levels they interface with. For example, a multiplexer, which joins DS-1 (T-1) channels to DS-3 (T-3) is called a M13 Mux. A M13 takes 28 T-1 inputs at 1.544 Mbps and interleaves them into a single T-3 output at 44.736 Mbps, adding additional signaling and control bits. See also M12, Multiplex, T-1, and T-3.

M23

Multiplex 2-to-3. A DS-3 (T-3) signal format that combines seven DS-2s (T-2s) to form a DS-3 (T-3). When T-3 technology first was developed, a M24 multiplexer (MUX) was used to combine 24 DS-0 channels at 64 Kbps into a single T-1 format at a total signaling rate of 1.544 Mbps, adding essential signaling and control bits in the process. Then a M12 combined four T-1s into a T-2 at a total signaling rate of 6.312 Mbps, adding more signaling and control bits. Then a M23 combined seven T-2s into a T-3 at a total signaling rate of 44.736 Mbps, adding even more signaling and control bits. Contemporary multiplexing generally combines these last two stages in a single M13 device. See also DS-0, M13, M24, T-1, and T-3.

M24

A T-1 service that allows a user to multiplex up to 24 voice or data channels into a single T-1 link, compatible with AT&T central office based channel banks (M24 compatibility generally refers to compliance with the channelization and coding techniques specified by AT&T TR62411).

M28

The telephone company multiplexing scheme that multiplexes 28 T-1 data streams onto a single carrier system, the T-3. See also M13.

M34

A designation for a multiplexer which interfaces between six DS-3s (T-3s) and one DS-4 (T-4) circuit.

M44

A T-1 service that allows up to 44 voice channels (48 without signaling) to operate over a single T-1 link by using ADPCM, and is compatible with AT&T central office based equipment. MJ44 compatibility generally refers to the ability to accept the 44 channel T-1 aggregate and break out one of the channels individually for routing purposes.

MA

Abbreviation for Milliamp or Milliamperes, unit of electric current.

Ma Bell

A term used to refer affectionately to the old AT&T and the old Bell System. Several Women's Lib organizations objected to it some years ago on the basis that there were no women in the higher corporate structure of AT&T, and that women, as over supervised operators, were the downtrodden majority within the Bell System. There was a movement afoot to change it to Pa Bell. But then came Divestiture and the breakup of the Bell System. The term Ma Bell now largely belongs in the history books. And there are now a handful of women in senior management in the Bell operating companies.

MAC

1. Moves, Adds and Changes. When you first install a phone system it will cost money to run wires and install phones all over the building. Very quickly you will notice that you'll need to move people and their phones, add phones for new people and change phones around. This will cost money, often lots of it. How much it will cost you depends on the arrangement you have negotiated with the vendor of your phone system. It's a good idea to get a good deal on Moves, Adds and Changes later on BEFORE you sign your original deal to buy the phone system.

2. IEEE specifications for the lower half of the data link layer (layer 2) that defines topology dependent access control protocols for IEEE LAN specifications. MAC is a media- specific access control protocol within IEEE 802 specifications. It currently includes variations for the token ring, token bus and CSMA/CD. The lower sublayer of the IEEE's link layer (OSI) which complements the Logical Link Control (LLC).

3. Mobile Advisory Council.

4. Multiply Accumulate. Computing functions accomplished by processors. Computers can multiply values, and can store both the multipliers (the original values) and the products (i.e., the end results of the calculations) in registers (temporary memory) for subsequent use. MAC speed and memory are embedded in silicon chip sets, including DSPs (Digital Signal Processors) used in telecommunications. See also DSP.

   See also MAC Address.

5. Shortened way of saying Macintosh, a line of computers from Apple Computer.

MAC Address

Medium Access Control Address. A MAC address (also called MAC name) traditionally is in the form of a 48-bit number, formally known as an EUI-48 (Extended Unique Identifier-48), which is unique to each LAN (Local Area Network) NIC (Network Interface Card). The MAC Address is programmed into the card, usually at the time of manufacture. The IEEE Registration Authority administers the MAC addresses scheme for all LANs that conform to the IEEE Project 802 series of standards, with such LANs including both Ethernet and Token Ring. The MAC address comprises two distinct identifiers (IDs), which typically are programmed into ROM (Read Only Memory) and which, therefore, cannot be changed. The first address is a unique 24-bit Company ID, also known as a Manufacturer's ID, which is assigned by the IEEE to the manufacturer of the NIC. The second address is a 24-bit Extension ID, assigned by the manufacturer. Also known as a Board ID, the Extension ID identifies the specific NIC, which is in the form of a printed circuit board. The Extension ID is intended to be unique, although occasional duplications occur, creating havoc. Unlike Network Layer Addresses, MAC names are location-independent, i.e. they stay with the card, which fits inside the device (e.g., workstation, printer, or server), which can move around. Destination and source MAC names are contained in the header of the LAN packet and are used by various devices (e.g., bridges, hubs, and switches) to filter and forward packets. The IEEE recently has enhanced the addressing scheme, expanding the Extension ID from 24 to 40 bits. This new addressing scheme is known as EIU-64, and is intended to provide NIC a globally unique identifier, which can be encapsulated in an IPv6 address. See also EUI-48, EUI-64, and Network Layer Address.

MAC Bridge

See Bridge.

MAC Layer

That layer of a distributed communications system concerned with the control of access to a medium that is shared between two or more entities.

MAC Name

A MAC name (also called a MAC address) is a 48-bit number, unique to each local area network card, that is programmed into the card, usually at the time of manufacture. Unlike Network Layer Addresses, MAC names are location-independent. Destination and source MAC names are contained in the LAN packet and are used by bridges to filter and forward packets. See also Network Layer Address.

MAC OS

The operating system powering the Macintosh line of computers from Apple Computer, Inc.

MAC Protocol

The procedures used to control access to a medium that is shared between two or more entities.

MACs

Moves, Adds and Changes. See MAC.

Machine Code

Same as Machine Language. See Machine Language.

Machine Dependent

Software which will only run (i.e. is dependent) on a certain computer.

Machine Directory

A Windows 95 definition. For shared installations, the directory that contains the required configuration files for a particular computer. The machine directory contains WIN.COM, the Registry, and startup configuration files.

Machine Language

A computer language composed of machine instructions that can be executed directly by a computer without further compilation. Instructions and data coded in binary code. Machine language is the native language of computer hardware. Machine language is the only language recognized by the microprocessor that controls all the operations in your PC. All programs and all data to be processed by your computer (PC, mini or mainframe) have to be translated into machine language at some stage.

Macintosh

A line of computers made by Apple.

Macro

1. MAChine ROutine. An instruction in a source language (e.g., FORTRAN) that is equivalent to a specified sequence of machine or assembler instructions. See Macro Language and Machine and Assembler.

2. A statement in software code that is expanded into one or more identifiers or statements and can consist also of one or more parameters. When invoked, a macro causes a list of conditions to occur.

3. Software which lets you alter the definitions of what the keys on your computer keyboard are. With a "macro" software program, you could change the letter "M" on your keyboard to type "Michael" every time you hit it. But this would be stupid. Better to hit a combination of letters to get "Michael." Most personal computers have extra non-alphabetic keys, like Control and Alternate. For example, type Ctrl-Alt M and bingo, the machine types "Michael Newton is a good son." Sometimes the origin of terms fades into the mist; like the software guru who recently admitted that he didn't know why it was called a "macro". That's easy, because it isn't a "micro".

4. Macro means very big. Random House's dictionary says it means "very large in scale, scope, or capability." Macro also refers to macroeconomics ” the study of bigger things in economics, like the factors that affect the wealth and growth of countries . In contrast, microeconomics focuses on factors that affect the wealth and growth of organizations, such as corporations.

Macro Language

A collection of instructions by which any kind of information in the system can be located and manipulated and by which new information types can be added to the system.

Macro virus

A computer virus implemented in a scripting language such as Microsoft's Visual Basic Script (VBS) that is run when a user opens an infected document in Excel or Word, or especially one attached to an email received by Outlook.

Macrobend Loss

Loss in optical power created when a lightguide (i.e., optical fiber) is bent in such a manner that it can be seen with the naked eye. See also Microbend Loss.

Macrobending

In an optical fiber, all macroscopic deviations of the fiber's axis from a straight line; distinguished from microbending.

Macroblock

The four 8 by 8 blocks of luminance data and the tow (for 4:2:0 chroma format), four (for 4:2:2 chroma format) or eight (for 4:4:4 chroma format) corresponding 8 by 8 blocks of chrominance data coming from a 16 by 16 section of the luminance component of the TV picture. Macroblock is sometimes used to refer to the pel data and sometimes to the coded representation of the pel values and other data elements defined in the macroblock header.

Macrocell

A large radio cell . SMR (Specialized Mobile Radio), also known as TMR (Trunk Mobile Radio), systems use macrocells. They work on the basis of a large omnidirectional (i.e., all directions) antenna placed on the highest spot in an area, in order to maximize the direct line-of-sight and, therefore, the quality of the signal. SMR systems generally cover a radius of 50 miles or so. That's a macrocell. A microcell is smaller. A picocell is smaller, still. See also microcell and picocell.

A macrocell is a new word for what we used to call a "cell," as in cellular radio. This is what some researchers at Bell Northern Research (BNR) wrote: "Today's cellular networks employ macrocells and are optimized to serve users in automobiles, moving at relatively high speeds. Yet, a growing proportion of cellular traffic is originating from users who are not driving in vehicles, but are on foot ... If a portion of the radio frequencies in a geographic area were transferred from macrocell (optimized for cars ) to microcell technology (optimized for pedestrians), cellular traffic would increase up to a hundredfold. Microcell networks will entail the deployment of many more transceivers than today's macrocell systems. However, microcell equipment will be less costly because it is low power, simpler and smaller, say the researchers at Bell Northern Research.

Macros

Software which lets you alter the definitions of what the keys on your computer keyboard are. With a "macro" software program, you could change the letter "M" on your keyboard to type "Michael" every time you hit it. But this would be stupid. Better to hit a combination of letters to get "Michael." Most personal computers have extra non- alphabetic keys, like Control and Alternate. For example, type Ctrl-Alt M and bingo, the machine types "Michael Newton is a good son."

Macstar

An old AT&T 3B2 computer-based software system that interfaces with the Remote Memory Administration System (RMAS) to effect customer moves and rearrangements on the 5ESS switch. The user needs only a terminal and printer.

Mad as a hatter

In the 19th century, workmen who used mercury , a poison , to cure beaver skins for top hats over time developed nervous twitches, drooled and spoke incoherently. Thus the expression, "mad as a hatter."

MADI

Multichannel Audio Digital Interface. MADI is an interface standard described by the Audio Engineering Society (AES) standards AES-10 and AES-10id. It was developed by Neve, Sony, and SSL as an easy way to interface digital multitrack tape recorders to mixing consoles.

MADN

Multiple Appearance Directory Number. An ISDN term. A telephone number that appears on multiple ISDN telephone sets.

MAE

A Network Access Point (NAP), or public peering point, where Internet Service Providers (ISPs) interconnect to exchange traffic at the national backbone level. The original MAEs were MERIT Access Exchanges, established by MERIT Access Exchange, which joined with IBM and MCI to establish the original public Internet backbone that replaced the NSFNET (National Science Foundation NETwork). MERIT subsequently was acquired by MFS, which then was acquired by MCI, which then was acquired by Worldcom to become MCI Worldcom. MAE East, the original MAE, is located in Vienna, Virginia, a suburb of Washington, D.C. MAE-West later was established in San Jose, CA. The term MAE then was used to denote either Metropolitan Area Exchange, or Metropolitan Area Ethernet ” it's your choice, as both Exchange and Ethernet are correct, despite ongoing Internet industry arguments over which is more appropriate. Actually, it's a moot point, since MCI Worldcom calls it just a plain MAE, which term it has trademarked.

Physically, a MAE is a building with zillions of wires, gigantic switches and computers with routing tables containing the locations of ISPs and how to get to them. MAEs and other NAPs are run by networking companies and carriers , to which ISPs pay a fee for the privilege of locating equipment there and exchanging traffic through the switches. Each MAE comprises a Gbps ATM switch, which supplements legacy FDDI switches. The ISPs connect to the MAE switch through various means, including Ethernet, FDDI and ATM. There also exist CIXs (Commercial Internet Exchanges), also called IXs (Internet Exchanges), which likewise function as public peering points. In order to minimize the cost of using these public peering points, consortia of ISPs have established regional private peering points, where they exchange traffic directly. See also CIX and NAP. For more on MAEs and charts of the traffic they carry, see www.nap.net/where/w_mae-east.html and www.mae.net/east.html. See also MAE-East.

MAE-East

MAE presently stands for Metropolitan Area Exchange or Ethernet. Both Exchange and Ethernet are correct. MAE is a huge interconnection point for Internet Service Providers (ISPs). They use MAEs for routing their internet traffic from customers on their network to Internet sites on other peoples' Internet networks. There are two MAEs ” MAE-East in Vienna, Virginia and MAE-West in San Jose, California. Physically a MAE is a building with zillions of wires, gigantic switches and computers with routing tables containing the location of Internet sites and how to get to them. MAEs are run by networking companies (MAE-East and MAE-West are run by MFS) and ISPs pay a fee to these networking companies to locate equipment there and for the transmission, switching and interconnect services. See also MAE (for a longer explanation) and Merit.

MAE-East++

An expansion of MAE-East, located in a nearby building. i++ (plus plus) gets its term from the C programming language where it means "use the current variable i and add 1." Plus plus has come to mean an expansion, an improvement, an upgrading, etc. See MAE and MAE-East.

MAE-West

See MAE.

MAE-West++

An expansion of MAE-West, located in a nearby building. i++ (plus plus) gets its term from the C programming language where it means "use the current variable i and add whatever one to it." Plus plus has come to mean an expansion, an improvement, an upgrading, etc. See MAE-East.

MAG Plan

Access charge reform adopted by the FCC in October 2001 that applies only to rate of return regulated carriers. It (1) increased the subscriber line charge (SLC): (2) phased out the carrier common line (CCL) charge; and (3) created an explicit and uncapped Universal Support mechanism, the Interstate Common Line Support (lClS).

Magalog

A mail order catalog disguised as a magazine in the hopes of confusing its recipients.

Magazine

1. Hardware unit, mounted in a frame, containing printed board assemblies.

2. From the Arabic "makhzan," a magazine is a "storehouse." The term is applied to some periodical publications that contain miscellaneous pieces such as articles, stories and poems, some of which may be illustrated in various ways. The first magazine was published In England in the 1730s, and contained nothing but short pieces snipped out of daily newspapers. See the Appendix for a list of magazines and other publications in computer and telecom.

Mageiricophobia

Mageiricophobia is the intense fear of having to cook.

MAGIC

Multidimensional Applications and Gigabit Internetwork Consortium. One of the Information Superhighway projects funded by the Information Technology Office (ITO) of the Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation (NSF). MAGIC is a gigabit-per-second ATM-based network connecting various high-tech research and development sites in Minneapolis (MN), Sioux Falls (SD), Lawrence (KS), Kansas City (KS) and Ft. Leavenworth (KS).

Magic Lantern

The is the name for the FBI's new magic software code which the FBI sends to a distant PC in an email. The email installs so called "keylogging" software that purports to encryption-key and password-sniff everything going on with that computer. Eventually the idea is to somehow grab the material produced by magic lantern and use it to figure out that computer.

Magic Wand

One of the devices used by con men when pretending to do TSCM (Technical Surveillance CounterMeasures). A magic wand is typically a field strength meter or box with many fancy lights.

Maggots

Telco slang for B-connectors, which are about the size and shape of fly larvae.

Magnetic Bubble

A device in which information is stored in a magnetic film as a pattern of oppositely directed magnetic fields. Magnetic bubble devices hold their memory even if you lose power.

Magnetic Core

Material used to store data in main memory.

Magnetic Disk

A computer storage device that records data bits as tiny spots on magnetic-coated disk platters. Hard disks and floppy disks are variations on magnetic disks. See also Magneto Optical and Holographic Data Storage.

Magnetic Field Strength

The magnitude of the magnetic field vector, expressed in units of amperes per meter (A/m).

Magnetic Ink

An ink that contains particles of a magnetic substance whose presence can be detected by magnetic sensors. Typical is the ink on your checks, which carry your name, your account number and the check's number.

Magnetic Medium

Any data-storage medium and related technology including diskettes and tapes, in which different patterns of magnetization are used to represent the values of stored bits and bytes.

Magnetic North

North based upon the magnetic compass or the earth's magnetic field.

Magnetic Storage

Any medium (generally tape or disk) upon which information is encoded as variations in magnetic polarity. The hard disk on your computer is magnetic storage.

Magnetic Stripe

A strip of magnetic material, usually tape, attached to a credit card containing data relating to the card holder. You have a magnetic stripe now on the back of most of your credit cards. That stripe tells a computer who you are, what your account number is, etc.

Magnetic Tape

A tape made of magnetic material upon which data may be stored for later retrieval by a computer.

Magneto

A small hand-cranked AC generator which uses permanent field magnets and can make electricity to ring telephone bells . See also Magneto Phone.

Magneto Optic

Relating to the change in a material's refractive index under the influence of a magnetic field. Magneto-optic materials generally are used to rotate the plane of the polarization. This phenomenon is how magneto optical disk drives work. The Magneto-Optic Effect also is known as the Faraday Effect.

Magneto Optical Drive

MO. A popular way to back up files on a personal computer. As the term implies, a magneto optical drive employs both magnetic and optical technologies to obtain ultra -high data density. A typical cartridge is slightly larger than a conventional 3.5-inch magnetic diskette, and looks similar. Data is written using magnetism (in the form of a magnetic field called the bias field) and light (a laser beam) to a disk that resembles a CD-ROM disk. A magneto optical drive holds huge amounts of information - as much as several gigabytes on a single disk. Introduced in 1988, the magneto optical drive (also spelled with a dash between the magneto and optical), the drive provides the convenience of the removability of floppies and the Bernoulli Box, the random access convenience of hard disk, the reliability of CD-ROMs and the promise of DAT-like capacity. But, according to PC Magazine, before you rush out and buy this ultimate storage solution, note that they're expensive, can't provide as much storage on one side of a disk as the largest hard disks and they're slower than today's hard disks. An explanation of how magneto optical drives work, courtesy PC Magazine: The recording layer on the disk stores the equivalent of binary 1s and 0s on the magnetic domains. The disk is designed so that the bias field by itself is to too weak to change the polarity of the magnetic domains. But when a spot on the disk is heated by a high- powered laser beam, its resistance to changing polarity drops . The bias field can now change the disk area's polarity. To read the disk, the drive uses a laser beam that is not hot enough to allow the bias field to change the disk area's polarity.

Magneto Phone

A magneto phone is a hand-cranked, self-powered phone, in contrast to the more modern "Central Battery" phone, which we typically have in our home and which derives its electricity from the distant telephone company central office, also called a telephone exchange.. A magneto phone has a hand-cranked magneto to generate ring current, and a local battery to power voice signals. Thus two magneto phones can be connected together via a simple pair of wires, without the need for a Central Exchange battery feed. More technically, a magneto phone contains a small hand-cranked AC generator which uses permanent field magnets to make electricity to alert the central office or another phone that it wants to make a phone call. A magneto phone has a crank handle on the side and a dial pad. It is a very old phone ” typically used around the turn of the 20th century. It is totally manual, self-powered. You crank the handle which turns a bunch of permanent magnets on the inside which in turns generates electricity which in turn is used to ring a bell at the central office. When that bell rings, an operator answers, asks which number the person wants to reach, dials and connects the call.

Magnetron

Alex Beam in the New York Times Book Review of June 16, 2002, writes , "In 1940, with the Battle of Britain hanging in the balance, Winston Churchill's top scientists came to America bearing a gift, and a plea. The gift was a palm-size copper disk called a magnetron, which could broadcast microwave radar beams farther and more precisely than any system in the world. The plea: Help us refine this invention, which could not only target enemy bombers but could also detect a U-boat periscope poking through the waves and even direct artillery fire against fixed positions , a precursor of today's much- vaunted "smart" weapons. The British scientists literally unpacked their bags for an audience of astonished American scientists at Alfred Loomis's Tuxedo Par New York estate, and the magnetron became, at once, the focus of Loomis's whole being." The book reviewed is called "Tuxedo Park, a Wall Street Tycoon and the Secret Palance of Science That Changed the Course of World Wall II" by Jennet Conant.

Alex Beam continues, "Loomis immediately convened an emergency meeting of the Establishment: his cousin Henry Stimson, the secretary of war; and Stimson's aides John McCloy, Robert Patterson and Robert Lovett. All Yale men, all Harvard Law, all Wall Streeters, all Republicans and all instrumental in starting M.I.T.'s wondrous Radiation Laboratory, the Rad Lab, which would not only develop the radar that helped win the war but spawned the microwave oven to boot."

MAHO

Mobile Assisted Hand-Off. A process in which the wireless mobile station assists the base station in assigning a voice channel by reporting its surrounding F signal strengths to the base station.

MAHR

Abbreviation for MILLIAMPERES HOUR, 1/1000th of an ampere hour . Term is commonly used with small rechargeable battery packs , such as those used by portable phones and laptop PCs.

Mail Bomb

1. A network security term. An attack in which a malicious user mails a dangerous program to an unsuspecting recipient. When the recipient runs the program, it performs some malicious action on their computer.

2. The flooding of an e-mail address with frequent messages, often done as an act of protest or harassment . See also Bozo Filter.

Mail Bridge

Mail gateway that forwards e-mail between two or more networks while ensuring that the messages it forwards meet certain administrative criteria. A mail bridge is simply a specialized form of mail gateway that enforces an administrative policy with regard to what mail it forwards.

Mail Enable Applications

Applications that use mail as a way of addressing and transporting information to and from users on a network.

Mail Exchange Records

See MX Records.

Mail Exploder

Part of an electronic mail delivery system which allows a message to be delivered to a list of addresses. Mail exploders are used to implement mailing lists. Users send messages to a single address (e.g., [e-mail]) and the mail exploder at somehost.edu takes care of delivery to the individual mailboxes on the lists, including Smith.

Mail Filter

A piece of software which lets a user sort his/her email messages according to information in the header.

Mail Flash

A cellular mail filter. Software that allows e-mail messages to be sent to a cell phone, first allowing the user to determine which messages are most important. Mail flash makes use of the SMS (Short Message Service) or WAP (Wireless Application Protocol) protocols. See also Mail Filter, SMS, and WAP.

Mail Gateway

A machine that connects two or more electronic mail systems (especially dissimilar mail systems on two different networks) and transfers messages between them. Sometimes the mapping and translation can be quite complex, and generally it requires a store-and-forward scheme whereby the message is received from one system completely before it is transmitted to the next system after suitable translations.

Mail Path

A series of machine names used to direct electronic mail from one user to another.

Mail Reader

Software which enables a user to select unread electronic mail and unread conferences messages and have them downloaded for reading off-line. Most mail readers also permit users to create responses off-line and upload them at their convenience.

Mail Reflector

An Internet term. A special mail address; electronic mail sent to this address is automatically forwarded to a set of other addresses. Typically, used to implement a mail discussion group .

Mail Relaying

A network security term. A practice in which an attacker " bounces " e-mail off another system's e-mail server in order to use its resources and/or make it appear that the mail originated from the other system.

Mail Server

Mail Server is the "post office" of a messaging network. Mail server is a computer host and its associated software that offer electronic mail reception and ( optionally ) forwarding service. Users may send messages to, and receive messages from, any other user in the system.

Mailbot

An email server that automatically responds to requests for information and sends that information by return email.

Mailbox

A directory or file on a computer somewhere that stores messages for a single user. A mailbox may include email, voice mail and/or facsimile documents. See also Unified Messaging.

Mailer

A piece of software that sends single or multiple emails.

Mailer Daemon

The Mailer-Daemon is not a person, but rather a computer program on Internet which runs automatically to perform the service of telling you why it could not deliver your email message. See Daemon.

Mailgram

An overnight electronic mail service of Western Union. The letter is phoned in or sent by computer to a central Western Union computer, from where it is sent to teleprinter machines located in post offices in major cities. When it's printed at the post office, the Mailgram is placed in an envelope and hand delivered by your friendly, local mailman in next day's mail.

Mailing List

A group of people to whom users can refer by a common name (for example, a mailing list called Marketing). When users address a message to a mailing list, all members of the mailing list receive the same message.

Mailto

A piece of HTML code that sits on a Web site and, through your browser, displays an email address underlined and in blue. When you click on this email address, this mailto HTML code automatically launches your email program and automatically inserts the email this <A HREF=mailto:[e-mail]>[e-mail]</A>. In this line, the second email address is what the person browsing your Web site will set in blue and underlined. When he clicks on it, the first email address will be what's dropped into the email as the address to send to. Typically the two are the same. But you could easily write it as: <A HREF=mailto:[e-mail]>email to Harry Newton</A>. In which case, "email to Harry Newton" in blue and underlined would appear when viewed through a browser by someone visiting my Web site.

Main

PBX or Centrex switch into which other PBXs or remote concentration of switching modules are homed . A PBX or Centrex connected directly to an electronic tandem switch (ETS). Also, a power source.

Main Cross-Connect

The interconnect point where wiring from the entrance facility and from the workstation is connected to telecom equipment.

Main Distribution Frame

MDF. A wiring arrangement which connects the telephone lines coming from outside on one side and the internal lines on the other. A main distribution frame may also carry protective devices as well as function as a central testing point. See Main Distribution Frame Fill, Distribution Frame and Frame.

Main Distribution Frame Fill

The central office mainframe is the termination point for outside plant cables. The "fill" is the percentage of pairs used by customers of the total number of pairs on the frame. Optimum fills vary based on the size of the central office and the amount of growth in the area. A low fill means idle lines and wasted investment in outside plant. A high fill, plus unexpected growth, forces budget busting and crisis construction projects.

Main Feeder

Feeder cable that transports pairs from the central office to branching or taper points.

Mainframe

1. One of the telephony synonyms for Main Distributing Frame.

2. Data processing term descriptive of very large computers.

Main Lobe

The main lobe is the area with the maximum intensity in the pattern of radiation produced by an antenna. One presumes it's called "lobe" because the pattern in a microwave signal of the main lobe typically looks like a ear lobe.

Main Memory

The principal random storage area inside the computer. Used for storing data and programs and under the direct control of the CPU ” the main processor. Also called RAM memory.

Main Network Address

In IBM's SNA, the logical unit (LU) network address within ACF/VTAM used for SSCP-to-LU sessions for certain LU-to-LU sessions. Compare with auxiliary network address.

Main PBX

A main PBX is one which has a Directory Number (DN) and can connect PBX stations to the public network for both incoming and outgoing calls. A main PBX can have an associated satellite PBX, and can be part of a tandem tie trunk network (TTTN). If the main PBX provides tandem switching for tie trunks, it is called a tandem PBX. In the context of ESN (Electronic Switched Network), a main PBX has tie trunks to only one node. See PBX.

Main Satellite Service

A PBX feature that allows multi-location customers to concentrate their attendant positions at one location referred to as the Main. Other unattended locations are referred to as Satellites.

Main Service Entrance

In AC electricity, the main service entrance is the necessary equipment, usually consisting of main circuit breakers or fuses, a switch and branch circuit breakers or fuses , in a grounded enclosure (panel) connected directly to earth. Located in the building at the point of entrance of the supply conductors from the power utility. Other panels in the building are referred to as branch, service or supply panels.

Main Station

A subscriber's telephone instrument, terminal or workstation used to originate and receive calls. Very often if two instruments have the same extension number (are bridged), one becomes the Main Station and the other is a bridged station for inventory purposes. See Main Station to Line Ratio.

Main Station To Line Ratio

A telephone company term. The ratio of main stations to lines. This ratio will normally be greater than 1.0 because of 2 and 4 party service, etc.

Main Terminal Room

The location of the cross-connect point between the incoming cables from the telecommunications external network and the premises cabling system.

Mainframe

A powerful computer, almost always linked to a large set of peripheral devices (disk storage, printers, and so forth), and used in a multipurpose environment at the corporate or major divisional level. A mainframe is a large-scale computer typically containing hundreds of megabytes of main memory and hundreds of gigabytes of disk storage. It is capable of "serving" thousands of "on-line" terminals. The term ” main frame ” derives from the racks that typically hold a large computer and its memory.

Mainframe Chiller System

Water-cooled mainframe computers rely on mainframe chillers for a continuous supply of liquid coolant to maintain processor temperature within a specified range. Exceeding the temperature specifications or an interruption of coolant flow can cause a sudden shut-down, interrupting of computer operations, and possible hardware damage, requiring costly repairs .

Mainframe Gateway

A hardware/software system that allows PCs on a LAN (Local Area Network) to communicate with a mainframe. A single, usually dedicated, PC acts as the gateway. PCs on the LAN share its hardware and its communication link, communicating with it over the LAN cable. The most common mainframe gateway is an SNA gateway, which hooks a LAN into an IBM mainframe.

Mainframe Server

Clients are devices and software that request information. Client is a fancy name for a PC on a local area network. It used to be called a workstation. Now it is the "client" of the server. A mainframe server is a large computer that stores lots of information and manages libraries of information. Here's a definition of Thin Client, courtesy of Oracle Corporation, writing in early 1994: "Mainframe systems store lots of data, but they're expensive, slow and difficult to use. Because all the processing happens on one large computer, they can't move large amounts of multimedia information to large numbers of users. Example, the IBM ES/9000, Amdahl's 5995-1400 or any plug compatible mainframe." See also Client, Client Server, Client Server Model, FAT Client and Media Server.

Mains

Some countries call their normal commercial power outlets ” "mains." In Europe the frequency of commercial power is 50 Hz. In the United States, its frequency is 60 Hz. It's hard to convert the frequency of commercial power. It's easier to convert voltage. In Europe and Australia, normal voltage is 240 volts. In the U.S., it's 120 volts .

Mains Modem

A modem which is part of a system called remote metering which monitors electricity usage and allows electric companies to offer such services as electronic mail, burglar alarms and energy management. The idea of energy management is that if the electric companies could turn off unnecessary appliances for a few hours during peak times, they might not have to build expensive new power stations. In exchange for that favor, they undoubtedly would be prepared to offer their customers price reductions.

Maintenance

1. All work needed to keep the telephone system operating properly, including periodic testing, repairs, etc. See Preventive Maintenance.

2. All work needed to keep a software program operating properly, operating on new machinery and operating with new management needs. Often, software maintenance means substantially rewriting the original software program. Most of the work done by data processing departments in large companies involves maintaining old programs. This is not a put-down.

Maintenance Acceptance

A term used in the secondary telecom equipment business. The point at which a maintenance company has tested a system, component, or peripheral device and determined that it meets manufacturer's specifications. The product can now be added to a maintenance contract. Once under contract, the maintenance company is responsible for repairing or replacing any defective components.

Maintenance Contract

Contract guaranteeing the repair of a PBX switch to support it at operational levels for a predetermined fixed term and fixed price.

Maintenance Control Center

MCC. A central place in a stored program control central office from which system configuration and trouble testing are controlled.

Maintenance Control Circuit

MCC. A voice circuit used by maintenance personnel over microwave links for coordination. This is not available to operations or technical control personnel.

Maintenance Hole

A vault located in the ground or earth as part of an underground duct system and used to facilitate placing, connectorization, and maintenance of cables as well as the placing of associated equipment, in which it is expected that a person will enter to perform work. Also called a manhole .