Fiber Optics Illustrated Dictionary - Part 65 docx

Media Access Control address, MAC address A MAC address is an important routing statistic widely used for managing data network transmissions.. Most memory in desktop computers is random

Fiber Optics Illustrated Dictionary

medium, if there is only one) This layer supports

multiple downstream and upstream channels Devices

such as network bridges are associated with the MAC

layer (or sublayer in OSI)

Mechanical Fiber Splice

For a mechanical splice to be effective, the fiber

filament ends must be precisely cleaved and aligned

to form a continuous lightpath without gaps or

par-ticles that could cause back reflection (top) The joint

must be firmly secured within a sturdy supporting

structure (e.g., the Corning Cable Systems

CamSplice™) to maintain the position ofthefilaments

relative to one another (bottom).

Mechanical splicing is only recommendedfor joints

that are well protected from strain and temporary

joints such as patch panels that require frequent

re-configuration For permanent splices, fusion splicing

is generally preferred.

Media Access Control address, MAC address A

MAC address is an important routing statistic widely

used for managing data network transmissions

Route-related devices typically keep a list or table of

MAC addresses which may be static or dynamic

Dynamic MAC address lists may be updated in a

va-riety of ways depending on the stability of the

con-figuration of a network and the size of a network

The MAC address is used by a network bridge to

de-termine whether a packet is to be forwarded By

copy-ing an incomcopy-ing source address to a MAC address

table, the bridge builds up a port-related "picture" of

device locations on the network Since there are

usu-ally efficiency trade-offs on large networks, with

machines being added and removed and MAC

ad-dress tables becoming large and unwieldy, certain

balancing mechanisms are built into bridge

manage-ment By limiting the lifespan ofa MAC address, the

system can be tuned to best serve the needs of the

network Thus, adynamic MAC addressthat has not

been used for a long time will be removed until a

transmission is again received from that source

Low-use special purpose addresses (e.g., emergency

sys-terns) that must stay active can be assigned astatic

MAC addressthat isn't automatically deleted

Media Access ExchangeMAX Asystem-level

net-work access unit from Ascend Communications, into

which peripheral cards can be inserted A MAX can

support multiple host ports or direct network

connec-tions, videoconferencing units, and remote LAN

con-nections

Media Access ProjectMAP.Animportant nonprofit,

public interest telecommunications law firm that

looks out for the First Amendmentrightsofindividuals

before the legal system and the Federal Communi-cations Commission (FCC)

Over the years, broadcast agencies have been pro-vided free use of the airwaves and, in return, have a legal responsibility to provide a portion ofprogram-ming and resources for the public good They are bound to uphold these obligations but may neglect them without citizen support groups like MAP, who take the time to lobby for the interests ofthe little guy

In recent years more free bandwidth has been broadly allocated to commercial broadcasters, particularly satellite broadcast frequencies

It is important that citizens safeguard their rights, and that it be impressed upon the government, the FCC, and the broadcasters that these broader free permis-sions have inherent corresponding responsibilities http://www.mediaaccess.org/

Media Access UnitMAU In Token-Ring local area networks (LANs), a wiring concentrator that connects the end stations The AU provides an interface be-tween the Token-Ring router interface and the end stations Also known as Access Unit (AU) See Multistation Access Unit

Media Interface ConnectorMIC An eight-pin modular 45-8 plug This resembles a common

RJ-11 phone jack except that it is wider to accommodate connections for eight wires This is the connector rec-ommended for audio-visual applications by DAVIC specifications

medium Earth orbitMEO An orbiting region around the Earth into which certain types ofcommu-nications satellites are launched, mid-way between low and high Earth orbits into which geostationary satellites are typically launched The lifespans ofme-dium-orbit satellites are about 10 to 12 years Most medium-orbit satellites travel about 10,000 to 15,000

kmoutside Earth A region called the Van Allen ra-diation belt between MEO and low Earth orbits (LEOs) is generally avoided MEO satellites are pri-marily used for broadcast applications See high Earth orbit, lCD, low Earth orbit, Teledesic

Meet MeAcommercial FTS2000 capability initiated

by dialing an access number at a prearranged time,

or as directed by an attendant, to establish a group conference call Additional conferees can join a con-ference in progress with an Add On concon-ference It may be necessary to make arrangements for a Meet

Me call several hours in advance, depending on how the system is administered See FTS2000

Meet-Point TrunkTelecommunicationtrunks con-figured for two-way traffic in jointly provided Switched Access Services (SAS), to interconnect End Offices and Tandems

mega-(abbrev -M)An SI unit prefix for 1 million, expressed as 106or 1,000,000 To confuse matters, when used in conjunction with computer-related quantities, it often means 220, expressed as 1,048,576 The most common ofthese uses is in descriptions of computer storage capacity as megabytes (MBytes),

in which 1MByte is 1,048,576 bits See kilo-

Megaco ProtocolAnetwork media gateway control protocol used between elements of a physically

Media Gateway and a Media Gateway Controller.

The Protocol was submitted as a Standards Track

RFC by Cuervo et a1 in November 2000.Itprovides

a general framework suitable for gateways,

multi-point control units, or interactive voice response units

to interact The protocol definition has common text

with ITU-T Recommendation H.248

A Media Gateway converts media from one type of

network to a format compatible with another type of

network The gateway may be able to process and

translate audio, video, or T.120 and can handle full

duplex media translations, in addition to playing and

executing media performances or conferences

Megaco Protocol connection model describes the

logical entities/objects within the Media Gateway and

can be controlled by the Media Gateway Controller

See RFC 3015

megger Aninstrument for measuring values of very

high resistance used, for example, for insulation

re-sistance testing See Wheatstone bridge

MelissaSee virus

Melles Griot lasersA line of lasers from the Melles

Griot optical company The firm is a leading supplier

ofgas lasers and is well-known for helium-neon

(Re-Ne) lasers Melles Griot also develops and

distrib-utes semiconductor laser technologies for research

and commercial applications In 1999, the firm

an-nounced acquisition of the Laser Power Microlaser

Group, developers of blue, green, and near-infrared

solid-stated diode-pumped lasers

Melpar modelAn artificial neuron used at the

Wright-Patterson Air Force Base in Ohio in the early

1960s to mimic human reasoning (or at least rodent

reasoning) The Melpar model, familiarly called

Artron by its inventors, was used as the "brains" of a

maze-running bionic mouse, physically resembling

the input mice used on today's computers The bionic

mouse brain comprised 10 Artrons, which was

suffi-cient for a trial-and-error method of learning to run

the maze With a clean slate, the mouse took 45

min-utes to complete the maze; eight tries later, it took

only 35 seconds See neural network

meltbackIn fusion splicing of fiber and other

mate-rials, the receding away from the point where the

fu-sion joint will occur Machines that perform

auto-mated fusion splicing are designed to move the two

ends to be joined closer together as they melt apart

at a speed that is appropriate for fusing the two ends

without excessive force or a gap Different materials

melt at different temperatures and will recede to

dif-ferent distances depending upon their diameter,

com-position, and environmental conditions

meltback testIn automated fusion splicing, a

pre-liminary setup test performed to determine how

quickly and how far a material melts back when heat

is applied to the ends intended to be fused This data

is then used to manually adjust or machine calibrate

the distance between the grooves or chucks holding

the two materials Adjusting fiber optic mass fusion

splicers is especially challenging as the heat from the

arc across a linear array of fiber filaments may not

Compensations in the arc or in the movement of the chuck (or both) as fusion takes place is necessary to ensure precise splicing See fusion splicing

memoryIn a computing system, a storage area that

is dynamically allocated and used by the operating system and various application programs Most memory in desktop computers is random access memory (RAM), although some programs will also allocate hard drive storage as "virtual memory." Memory is one ofthe most basic elements of a com-puting system, along with the central processing unit (the CPU often also incorporates memory internally) and the input/output (I/O) bus

Read only memory (ROM) is included in many com-puters to provide basic nonvolatile operating param-eters to a system, particularly on startup.Inthe earli-est microcomputers, a programming language was sometimes included in ROM Random access memory (RAM) is dynamically allocated py the sys-tem and applications programs RAM is further dis-tinguished as static or dynamic RAM Most desktop systems include about 8 to 64 Mbytes of RAM, and may be extended up to 64 or 256 Mbytes RAM typi-cally operates at about 60 to 80 ns, although this may change as newer, faster types of memory are devel-oped

Most types of computer chip memory are volatile, that is, the contents will disappear ifthe system is not constantly powered and refreshed However, there are some types ofchips that can retain information, such

as erasable, programmable, read-only memory (EPROM) chips

The price ofmemory fluctuates dramatically.In1986,

a megabyte of RAM was $600 U.S.; by the early 1990s this had dropped to $25, then increased again

to $120 By early 1998, the price was down to $4 per megabyte and dropped to $1 in 2001

Programmers tend to write code that fills available space This results in applications that require more memory than many consumers have, setting off an-other round ofbuying.In1978, the TRS-80 computer ran with 4 Kbytes of memory, and with 8 Kbytes it could do word processing and spreadsheet applica-tions quite well By the mid-1980s, the Amiga com-puter could multitask and run graphics programs con-currently with stereo sound quite comfortably in 4 Mbytes ofRAM Systems in the late 1990s rarely ran efficiently with less than 16 Mbytes, and most ven-dors recommended 32 Computers now commonly come installed with 256 MBytes or more

MEMSSee micro-electromechanical system

Mensa Single Fiber Supertrunk System Acommer-ciallinear, synchronous, high bandwidth, point-to-point optical transceiver system designed specifically for supertrunk applications, distributed by Synchro-nous.Itmay be used for all analog or hybrid analogi digital signals at 200 MHz It uses a 1550 om DFB laser diode light source modulated by a Mach Zehnder The receiver is based upon a high-response PIN photodetector

The system provides dual-trunk performance over a

Fiber Optics Illustrated Dictionary

single optical fiber linle For international operation,

Band V channels can be directly carried External

modulation enables the system to be used with

stan-dard installed cable and is said to eliminate laser

chirp The transmission link can be optically split or

repeated

mercury vapor lamp A lamp in which mercury

va-por flows back and forth through a tube when made

horizontal to complete the electric circuit and start

the lamp Ionized mercury vapor is then produced by

the heat and current, creating light through the length

of the tube The light is very bright, with a greenish

glow, and is generally used in industrial applications

See fluorescent lamp

mesh topology Atype of circular network backbone

topology in which data can travel back along the

backbone if a node becomes unavailable due to a

dis-ruption, such as line breakage or failure The mesh

nature of the topology stems from the appearance of

the connections between a node and other nodes

sev-eral nodes away Some vendors and users prefer this

over a ring topology as more than one route can lead

to a particular location on the network See topology

message circuit noise On a correctly terminated

cir-cuit in a network, the background noise that exists

when there is no test signal The noise may arise from

crosstalk, radio frequency interference, power line

harmonics, or thermal noise Noise is usually assessed

by passing the noise through selected filters to

deter-mine its source and character

Message Handling System MHS On a network,

MHS provides a means to store and forward messages

among MHS users or applications Unlike traditional

telephone networks and the early two-way radio

com-munications, most data networks do not need to

es-tablish an end-to-end connection before carrying out

communications Thus, the MHS provides a way to

handle the messaging traffic under dynamic

circum-stances See XAOO under X Series

Recommenda-tions

Message Security Protocol MSP A Secure Data

Network System (SDNS) protocol for providing

XAOO message security With MSP, a message is

given connectionless confidentiality and integrity,

data origin authentication, and access control;

nonrepudiation with proof of origin; nonrepudiation

with proof of delivery

MSP is a content protocol, in the application layer,

and is implemented within originator and recipient

MSP user agents.Itis an end-to-end protocol that

does not employ an intermediate message transfer

system MSP processing is carried out prior to

sub-mitting a message and after accepting delivery of a

message

AnXAOOmessage comprises a content and an

enve-lope With MSP, a new message content type is

de-fined with a security heading encapsulated around the

protected content

Three types ofX.509 digital certificates are supported

by MSP The user's distinguished name and public

cryptographic material are bound within an X.509

certificate which, inturn,is signed by a certification

authority (CA) The CA manages X.509 certificates and Certificate Revocation lists

message switching A means of switching and

mul-tiplexing data packets by storing, queuing, and for-warding the message to the recipient See circuit switching, packet switching

Message Transfer System MTS Ageneral-purpose,

application-independent, store-and-forward commu-nications service within a Message Handling System (MTS) The MTS uses message transfer agents (MTAs) to relay messages See Message Handling System

message unit In packet networking, SNA, a basic unit

of data processed by any layer

meta-signaling A means to manage User Network

Interface (UNI) vacant codes (VCs) signaling and associated broadcast channels incorporating a user part and a network part Meta-signaling establishes point-to-point signaling VC and broadcast signaling

VC (general broadcast and selective broadcast) Metal Vapor Laser Variation - Schematic

This schematic illustrates a variation on metal va-por lasers to make them more efficient without requir-ing increasrequir-ingly complex or unwieldy tubes.

Voltage is transmitted through a choke coil (10), a charging diode (ll), and a charging resistor (13) into the storage capacitor (12) The switching device (14) stimulates the capacitor to discharge its storedpower into the circuit in the form of a preliminary charge between the cathode (2) and the grid (4) which pro-vides variable impedance This triggers the main dis-charge between the cathode and anode (3) The grid also serves as a discharge "buffer, " improving the life-time ofthe componellt [US patent #6,229,837, May 2001.}

metal vapor laser A type of atomic gas laser that

ef-ficiently emits light in the visible spectrum A rare-gas metal vapor laser can also emit light in invisible ranges Metal vapor lasers may be classified as neu-tral (e.g., gold, copper lasers) or ionized (helium-cad-mium lasers) Traditionally they have been based upon a two-electrode structure to create a discharge pulse, though inventors such asA.Ozu have proposed variations that enable higher efficiency with a grid electrode placed near the electron-generating cathode

to provide a preliminary discharge

ian metal vapor laser (He-Cd) in 1970 The

Bulgar-ian Academy of Sciences includes the Metal Vapour

Laser Laboratory in Sofia, Bulgaria

Metcalfe, Robert(1946- ) An American engineer

and journalist, Metcalfe is the acknowledged creator

ofEthernet at Xerox PARC in 1973, along with David

Boggs In 1979 he founded the 3Com Corporation,

and since 1990 has been involved with a number of

publishing organizations See Boggs, David;

Ether-net

METEOSATMeteorology satellite

meterA metric linear measure of length/distance

equal to 3.28 feet or 39.37 inches Europe, Canada,

and many other regions are standardized on metric

measures The u.S continues to use the British units

oflength (e.g., yard) except in scientific circles, where

metric is used

Metropolitan Area Network MAN.An urban

net-work ofhigh-speed hosts SeeMAEEast,MAEWest,

SMDS

Metropolitan Fiber SystemsMFS A Competitive

Access Provider (CAP) founded in the late 1980s In

the 1990s it established its own backbone, providing

national network services It was subsequently

ac-quired by WorldCom

Metropolitan Service AreaMSA An administrative

designation used by many organizations providing

commercial and public services in urban areas The

u.S Government uses the designation for managing

and analyzing data from the national census A

Met-ropolitan Service Area is a city with at least 50,000

residents or an urban area with at least 100,000

resi-dents within the counties encompassing these areas

The Federal Communications Commission (FCC)

has used this census designation to recognize over

300 MSAs for the purposes ofassigning

telecommun-ications licenses such as cellular telephone licenses

See Rural Service Area

Meucci, AntonioAn Italian-born Cuban inventor,

chemist, stage designer, and engineer, Meucci made

many pioneering discoveries in telecommunications

concepts and devices, but his findings were not

widely communicated to others, and hence not

cred-ited as to their impact on subsequent inventions such

as telegraphs and telephones, which made

telecom-munications history

Meucci developed rheostats, electroplating

tech-niques, and experimented with passing electricity

through the human body While studying mild

elec-trical charges, he discovered the "electrophonic"

ef-fect, which related nerve responses to specific

appli-cations of current through a wire By the mid-1800s

he had developed several devices for creating a

vi-brating electric current from spoken acoustical

im-pulses By using a copper strip and delicate animal

membranes as diaphragms, he created one ofthe

ear-liest telephone-like mechanisms He emigrated from

Cuba to the u.s and applied for a caveat for his

teletrofonowhich was granted in December 1871, 4

years before the patent ofAlexander Graham Bell and

the caveat of Elisha Gray It is believed that Bell (and

Meucci's invention and, due to greater resources and celebrity, overshadowed his inventions See tele-phone history

Meyer codeAflag signaling code, employing left and right motions to create characters or syllables, and a forward motion to indicate ends or pauses This code was in use until it was superseded in the First World War by International Morse code and American Morse code See semaphore

MFJSee Modified Final Judgment

MFSSee Metropolitan Fiber Systems

MFSKSee multiple frequency shift keying

MH See Modified Huffman

mhoApractical unit ofthe measure of conductance,

so named because it is ohm spelled backwards See

admittance, ohm

MHS See Message Handling System

MID See Management Information Base

Michelson interferometerSee interferometer MicralThe first fully assembled 8008-based micro-computer, the Micral featured 8-bit processing and 2 Kbytes of memory It was designed in France by Fran~ois Gemelle The Micral sold for just under

$2000, and, like its predecessor the Kenbak-l, was not commercially successful in the United States, an important market for microcomputers It was intro-duced in May 1973 before the SPHERE, Scelbi-8H, Mark-8, and Altair computers See Altair, Kenbak-I, Mark-8, MITS, Scelbi-8H, Simon, SPHERE micro-electromechanical systemMEMS Technol-ogy for integrating electromechanical functions into integrated circuits MEMS-based actuators are used

in single- and multimode fiber optic switches microbendIn fiber optic cables, a small inconsis-tency, nick, or slight bend that might be introduced into the fiber during manufacture or installation or may occur after installation due to wear and tear Microbends may introduce small changes in the op-tical transmissions path as the light "bounces" through the fiber, but are not likely to significantly degrade the signal However, ifthe fiber is especially slim or the wavelengths especially long, microbend losses may occur If there are a large number of microbends, the accumulated effect ofthe disruption over distance, especially in a cable with a small core radius, may be significant See loss, macrobend, macrobend loss

MicroCal Module Anew type of integrated circuit (IC) designed to facilitate self-monitoring in virtu-ally any type of wireless equipment, including base stations, mobile handsets, and subscriber units The MicroCal Module scans the entire bandwidth, gath-ering data which is then fed back to a central mainte-nance center The module, designed by Micronetics Wireless, was awarded a u.s patent in 1996 Micronetics is working with a number ofcompanies, including Nortel and Motorola, to integrate the mod-ule into wireless infrastructure equipment

Microcom Networking Protocol MNP.A series of proprietary error control and data compression pro-tocols designed for dialup modems, which are often

Fiber Optics Illustrated Dictionary

used in conjunction with industry standard

ITU-T-recommended error control mechanisms

For example, MNP-4 works with modems that

trans-mit at data rates up to 14,400 bps MNP-4 is often

implemented in conjunction with the VA2 error

con-trol protocol standard from the ITU-T See Microcom

Networking Protocols chart See Y.42

microfiche Asomewhat standardized optical archive

system using thin transparent sheets of

image-carry-ing plastic for storimage-carry-ing scanned printed matter,

espe-cially newspapers, books, journals, etc Since

micro-fiche information is miniaturized to fit as much data

on a sheet as possible, it is typically not

human-read-able without magnification Microfiche machines

backlight and magnify the data Some photocopiers

are designed to enlarge and print microfiche

infor-mation, although the copies are often not very clear

Digital storage techniques are replacing microfiches

and the quality is improving over earlier scans

Un-fortunately, like microfiche archives, the originals are

often destroyed for lack of storage space and funds

Microfiches are common in libraries, post-secondary

institutions, and government archives but are being

gradually superseded by scanned digital images

micromachined membrane deformable mirror

MMDM A compact component for correcting

aber-rations in optical systems, such as distortion that may

be caused by passing through an aperture or lens.In

contrast to traditional glass lens correction devices,

a MMDM is a thin membrane coated to give it a

highly-reflective surface Gold and aluminum

coat-ings are common The speed ofresponse ofMMDMs

is faster and astigmatism is somewhat lower than

other popular technologies (e.g., OKO mirrors)

By application of current through actuators

incorpo-rated into the membrane system, the shape of the

membrane can be controlled through an attracting

electrostatic force The system is commonly set up

with a flat spherical MMDM which is shaped as needed

MMDMs have been found practical in the visual spectrum and have been studied for their effect at su-percooled temperatures See wavefront control microphone A device for apprehending sounds and transmitting them electrically or acoustically to a re-ceiver or audience A very simple microphone can be created by wrapping stiff paper into a funnel shape, attaching it to a string or wire, and stretching it to a receiver- another funnel on the other end If the lis-tener puts an ear near the receiving funnel while the speaker talks into the microphone funnel, the sound, while not loud, can be heard across a room Add elec-tronics to amplify the signal, and you have a basic microphone Some microphones also include echo acoustics to make the sound of a voice more reso-nant Many singers use this type of microphone to enhance their singing on recordings

Microphones are widely used in camcorders, film cameras, tape recorders, and video recorders Two microphones are needed for true stereo sound Microphones can be used as peripherals with com-puters for the creation of music and other sound samples, or for videoconferencing See sampling, videoconferencing

Microsoft BASIC A BASIC interpreter first released for the Altair computer in 1975 Paul Allen had seen the feature article on building the Altair in the Janu-ary 1975 issue ofPopular Electronics, so he and Gates talked about it in Harvard Square, and con-ceived the idea ofwriting a BASIC interpreter for the new kit-based machine They contacted MITS, made

a proposal, and set to work creating a BASIC that could fit into 4K of memory The entrepreneurs had previous experience in looking at code for interpret-ers for various languages based on their business ac-tivities together through high school, and 8K BASICs

Microcom Networking Protocols

MNP-l Asynchronous mode, half duplex transfer operation

MNP-2 Simple error correction scheme, asynchronous mode, full duplex operation

MNP-3 Error correction incorporated, synchronous mode

MNP-4 Error correction incorporated, increased throughput Often included with Y.42

modems, along with MNP-5 data compression

MNP-5 Simple data compression scheme Often included with Y.42 modems, along with

MNP-4 error control

MNP-6 Statistical duplexing and Universal Link Negotiation Full duplex emulation

MNP-7 Data compression scheme included

MNP-8 MNP7 for modems which emulate duplex operation

MNP-9 Data compression scheme included Incorporates Y.32 technology

MNP-1O Dynamic fall-back and fall-forward adjusts modulation speed with link quality

BASIC in a simulation environment, since it wasn't

practical to writeiton the Altair itself Allen created

a simulation environment for 8080 programming

code and modified a symbolic debugger to understand

the 8080 instructions Gates laid out a design for the

BASIC interpreter modeled on the BASIC he had

en-countered on a timesharing system at Dartmouth and

began codingit,with assistance later from Allen

Monte Davidoff contributed some of the math

rou-tines, especially those for floating point operations

On the plane to Albuquerque to demonstrate the

soft-ware, Allen created a bootstrap loader so the Altair

would be able to read the data into memory, using a

teletypewriter as an input mechanism (Gates later

streamlined the bootstrap loader.) On the first run at

the demonstration at MITS, the BASIC didn't work

On the second try it did This was a substantial

achievement, given the short, hands-offdevelopment

period and environment

This first BASIC was later ported to many machines

Not long after the Altair kicked off the

microcom-puter industry, Microsoft BASIC Level II was

bundled with the TRS-80 Model I in ROM in 1976,

replacing Level I BASIC, and included with the

Com-modore PET Microsoft also contributed some

rou-tines to the Integer BASIC designed by Wozniak for

the Apple Computer, resulting in AppleSoft BASIC

Later, in 1984, Microsoft BASIC was incorporated

into ROM on the ffiM Personal Computer XT In

addition to the computer-specific 8-bit operating

sys-tems, BASIC was ported to run on the popular CP/

M-80 operating system designed by Gary Kildall At

this point, Microsoft BASIC was still a text-based

program

Microsoft BASIC version 2.0, the first graphics-based

BASIC for the Macintosh, was not announced until

fall, 1984, a decade after the text version shipped In

1985, Microsoft provided a windowing version on

floppy diskettes for the Amiga 1000 Later Microsoft

BASIC evolved further into Microsoft Visual BASIC,

which differed chiefly in that graphically entered

structures could be used to automatically generate

code See BASIC, Visual BASIC

Microsoft Data Warehousing Framework A

Microsoft commercial open, scalable architecture for

creating, using, and managing integrated data

ware-housing applications

Microsoft Data Warehousing AllianceDWA,

MDWA Atrade association for those using and

sup-porting Microsoft Data Warehousing Framework

in-formation technology (IT) applications and standards

Microsoft IncorporatedOne of the earliest

compa-nies supporting the microcomputer market,

Micro-soft was founded by Paul Allen and Bill Gates in 1975

following their partnership as Traf-O-Data, which

they formed around 1972 Although Gates and Allen

had worked on programming projects together

dur-ing high school in Seattle, they formalized Microsoft

in 1975 in order to market a version of interpreted

BASIC for the Altair computer The trade name was

registered in 1977

Electronicsarticle he saw in Harvard Square Since the Altair so closely paralleled an earlier microcom-puter hardware idea of his, he contacted Gates to let him know "someone else is doing it." They then talked in the Square about writing BASIC for the new machine They contacted MITS, the makers of the Altair, and Allen, Gates, and Davidoffcreated a BA-SIC based on Gates' and Allen's experience with BASIC interpreters at Dartmouth Six weeks later, Allen flew south and successfully demonstrated BA-SIC to MITS in New Mexico, setting the groundwork for their software development company

The entrepreneurs moved their operations first to the Sundowner Motel across the street from MITS, and later to an eighth floor office in Albuquerque, New Mexico Allen took a position as VP of Software at MITS, while keeping in regular contact with Micro-soft and Gates They hired high school friends to help out Meanwhile, Gates began enhancing BASIC and porting it to new platforms that were introduced When Gates briefly went back to Harvard, Ric Weiland and Marc McDonald formed the core at Microsoft Marc McDonald designed and coded Stand-alone Disk BASIC, in consultation with Bill Gates In the late 1970s, Microsoft BASIC was adapted to run on a popular text-oriented operating system called CP/M, developed in various versions

by Gary Kildall of Digital Research between 1973 and 1976

After three years in New Mexico, Microsoft relocated

to Bellevue, Washington, near the co-owners' fam-ily members At this location it was easier to recruit programmers as well Microsoft now has a campus

in Redmond, Washington, and has grown to be a large, financially successful enterprise

While it has had occasional forays into hardware de-velopment, the primary focus of the company has been software, and a substantial portion of the rev-enues are derived from operating systems and busi-ness-related applications Paul Allen left the company

to invest in a number of other ventures, and formed the Paul Allen Group to oversee his various invest-ments Allegations ofunfair business practices were leveled at Microsoft on numerous occasions during the late 1980s and the 1990s, and the company be-gan to be scrutinized by the U.S Justice Department These proceedings are ongoing and are still not com-pletely resolved Bill Gates was the long-standing CEO until January 2000 when he resigned in lieu of Steve Ballmer who took the positions ofpresident and CEO Gates continued as chairman and chiefsoftware architect See Allen, Paul; Altair; Gates, William; MITS; Traf-O-Data

Microsoft Mobile ExplorerMME Amultistandard microbrowser emulation environment optimized for low-resource devices such as mobile telephones ca-pable of displaying HTML-like markup language pages See browser, PDA microbrowser

microwaveA radio wave transmission frequency (1000+ MHz) generally used for radar and radio re-peaters Microwaves also provide the cooking power

Fiber Optics Illustrated Dictionary

for microwave orradar range ovens The generation

of microwaves was initially achieved with

magne-trons and Barkhausen-Kurz tubes in the early 1920s

Microwaves were sometimes called radio-optical

waves in the early days of their development due to

their position on the electromagnetic spectrum

be-tween light waves and conventional radio waves, and

because some of their characteristics, such as

propa-gation, were similar to light waves

Microwave relay systems were in use as early as the

1930s by AT&T The original magnetrons were

de-veloped into cavity magnetrons and traveling-wave

tubes Microwave generators and relays are now an

important aspect ofsatellite communications

Micro-waves are also finding increasing use in connecting

local area wireless networks (LAWNs) While they

are not used for the primary information-carrying

aspects within the network, they are useful for

inter-connecting line-of-site separated LAWNs, or LANs,

between buildings Connection requires a license

from the Federal Communications Commission

(FCC) See magnetron, microwave antennas, short

wave, traveling-wave tube

Microwave Antenna Structures

Parabolic antennas constructedfrom mesh or solid

materials are usedfor very short (microwave) radio

waves The curvature ofthe dish and the

relatedplace-ment oftransmitting or receiving horns are important

to the quality of the signal transmitted or received.

[Classic Concepts photos; used with permission.}

microwave antennaDue to the very short

wave-lengths used in microwave transmissions, the

physi-cal arrangement of microwave antennas is quite

different from those for UHF, VHF, and FM

broad-casts Microwave transmissions are directional for

both up- and downlinks, quite different from the

roughly isotropic, omnidirectional character of

tra-ditional television and radio broadcast waves The

common multibranched Yagi-Uda style antennas and fan dipole antennas are inexpensive and appropriate for VHF and UHF reception, but directional parabolic antennas are the norm for microwave signals The diameter of a parabolic dish antenna is a mul-tiple of the length of the microwaves received and typical dishes range in size from about 2 to about 10 feet across, with the curvature of the dish determin-ing the position of the feed hom which focuses the beams

The first transcontinental microwave communication system began operations in 1951 through a system

of relay stations between San Francisco and New York City Within three years, there were more than

400 additional stations scattered across North America See antenna, parabolic antenna, UHF an-tenna, VHF antenna

microwave multi-point distribution system MMDS MMDS is a system for distributing cable TV programming through microwave communications, more commonly known now as wireless cable MMDS works in the frequency range of2.50 to 2.686 GHz, and MMDS service providers are increasing in number The signals are downlinked from the satel-lite to the local transceiver, and broadcast from there

to subscribers within about a 50-mile radius, depend-ing upon terrain The subscriber receives the signal

on a consumer-priced antenna mounted on or near the home, which is linked through a cable to a "black box" connected to (and sometimes sitting atop) the

TV receiver This box decompresses compressed digital signals and unscrambles signals intended to prevent unpaid/unauthorized viewing of the pro-grams The MMDS system is in the process ofchang-ing from analog to digital technology, openofchang-ing up op-portunities for digital multiplexing through highly linear radio frequency (RF) subsystems, thus provid-ing more television channel choices for viewers microwave radarRadar systems employing micro-waves have been extremely importantinnavigation, tracking, surveillance, guidance, and communications systems Much of the early researchinmicrowave radar was conducted at the Massachusetts lnstitute ofTechnology (MIT) radiation laboratory in the early 1940s

Mid-Span MeetAninterconnection point between two co-carriers The Mid-Span Meet is the point up

to which the carriers provide cabling and transmis-sions

MIDISee Musical Instrument Digital Interface

MIDI time code MTC Astandard developed to iden-tify timing information associated with a stream of Musical Instrument Digital Interface (MIDI) data See SMPTE time code

MIDPSee Mobile Information Device Profile Midwestern Higher Education Commission MHEC MHEC was founded as an interstate agency

in 1991 to promote resource sharinginhigher edu-cation As a subgroup, it includes a Telecommunica-tions Committee that takes a regional approach to improving access, services, and costs oftelecommu-nications services

man RightsThis declaration was put forth in 1998,

based in part on anumber ofglobal rights documents,

including the Universal Declaration of Human

Rights, the International Covenant on Civil and

Po-litical Rights, the American Convention on Human

Rights, the European Convention for the Protection

of Human Rights and Fundamental Freedoms, the

Beijing Platform of Action, and other important

ac-knowledgments of human rights

The Declaration asserts the intrinsic relationship

be-tween freedom of opinion and expression and the

technologies and venues available for their

commu-nication.Itdeclares that "The Right to Communicate

is a universal human right which serves and

under-pins all other human rights and which must be

pre-served and extended in the context ofrapidly

chang-ing information and communication technologies, "

It affirms the need for equitable access to all

com-munications media coupled with the mandate to

pre-serve and sustain cultural rights and diversity It

un-derlines the importance of not reducing all

informa-tion users to the category of consumers and affirms

their role as communications producers and

contribu-tors It calls for international recognition of

commu-nity broadcasting as a vital contributor to human

free-doms See People's Communication Charter The text

of the Milan Declaration is available through the

World Association of Community Broadcasters

(AMARC) http://www.amarc.org/

Mill Street plantThis historically significant power

plant began providing three-phase alternating current

(AC) in 1893 Partly due to the advocacy ofT

Edi-son, most early power plants provided direct current,

so the Mill Creek No.1 hydroelectric plant was a

pre-cedent-setting installation, and many other similarAC

power suppliers followed its example

milli-(abbrev -m)AnSI unit prefix for 1thousandth,

10-3or 0.001 Thus, a milliamp is 1 thousandth of an

ampere

MILNETMilitary Net The ARPANET was a

his-toric computer network put into operation in 1969

In 1975, ARPANET was transferred to the Defense

Communications Agency Then, in 1983 it was split

into MILNET for military usage, and ARPANET,

which evolved into the Internet MILNET is used for

nonclassified U.S military communications See

ARPANET, Internet

MilstarAjoint U.S ArmylNavy/Air Force satellite

system for providing jam-resistant communications

for wartime requirements for high-priority military

users It is a global constellation of 5-ton

geostation-ary satellites orbiting at about 22,250 nautical miles

The first Milstar satellite was launched in February

1994, the second in November 1995 Six launchings

are intended to support four satellites that are active

at anyone time The satellites have operational

life-times of about 10 years

Milstar was designed to link ground, marine, and air

command authorities The satellites relay

communi-cations from terminal to terminal, anywhere on Earth

By transmitting from satellite to satellite, ground hops

nals provide a variety of data services, including voice, data, facsimile, or teletype communications MIME See Multipurpose Internet Mail Extension

MINSee Mobile Identification Number

Miner, Jay( 1930-1994) A gifted design engineer responsible for designing the hardware for the Atari

800 computer, the Amiga computer, and the Lynx color handheld game machine In 1982, Minerjoined

Hi Toro to develop the Lorraine computer, which was subsequently sold as the Amiga by Commodore Busi-ness Machines Aproponent ofopen-mindedBusi-ness and creativity, Miner included his dog's pawprint inside the case of the Amiga 1000 After the Amiga, he cre-ated the Atari Lynx, a fast color handheld game ma-chine Jay Miner was affectionately known as Padre, the Father of the Amiga, to the computing commu-nity Following a serious illness and kidney trans-plant, Jay Miner devoted his remaining working life

to developing medical devices, such as pacemakers,

to aid society Surprisingly, despite the fact that he understood that the creation of the Amiga' was a re-markable achievement, Miner didn't anticipate the revolution in the video industry launched by his cre-ation In a computing industry where hardware archi-tectures go out of date in a few months, the viability

of the Amiga hardware for more than a decade, par-ticularly for graphics and sound, is a tribute to its ef-ficient and insightful design See Amiga computer, Commodore Business Machines

minifloppyA generic term for a number of floppy diskette technologies that store almost ten times as much data as a regular 3.5-in floppy, but which are designed by some manufacturers to be downwardly compatible with 1.4-Mbyte drives The price ofstor-age on these high capacity floppies is substantially cheaper, and they may, in time, supersede current floppies

minimal shift keyingMSK A type of modulation technique similar to quadrature phase shift keying (QPSK), except that the rectangular pulse in QPSK

is a half-cycle sinusoidal pulse in MSK See modu-lation, phase shift keying

minimize button, iconize buttonGraphical user terfaces on several different operating systems in-clude a small gadget on application or display win-dows which, when clicked, will shrink the window down to an icon Thus, the program is available and can quickly be retrieved by double-clicking the mini-mized icon without shutting down the process and rerunning the program

Ministere des Postes et TelecommunicacionesThe telecommunications authority for the Democratic and Popular Republic ofAlgeria Online communications are in French

Ministerio de ComunicacionesThe telecommuni-cations planning and regulatory authority of the Re-public of Columbia in South America

http://www.mincomunicaciones.gov.co/

Ministry ofInformation Technology and Telecom-municationsMITT The Mauritius ministry that handles the formulation and implementation of

Fiber Optics Illustrated Dictionary

government policies in telecommunications and

in-formation technology Telecommunications are

gov-erned by the Mauritius Telecommunications Act

1998 Online services are designed and published by

the National Computer Board

http://ncb.intnet.mulmitt.htm

Ministry of Posts and Telecommunications MPT

The Japanese radio regulatory administration, MPT

oversees radio communications, based upon the

Ra-dio Law of 1950 The MPT grants raRa-dio station and

operator licenses, monitors and inspects stations and

radio frequencies, and sets technical standards for

ra-dio equipment http://mpt.go.jp/

Ministry of Telecommunications The

telecommu-nications authority of the Lebanese Republic under

the direction ofthe Minister ofPost and

Telecommu-nications http://www.mpt.gov.lb/

Ministry of Telecommunications and

E-Com-merce The authority in Bermuda that oversees

tele-communications, broadcasting, and frequency

admin-istration http://www.mtec.bml

Minitel AFrench Telecom service that provides free

terminals for chat and electronic telephone directory

videotext services It is similar to the German

Bundespost's interactive videotext system See

Minitel

MIPSee Multichannel Interface Processor

MIPGSee Multiple-Image Portable Graphics

MIPSmillion instructions per second A measure of

processor speed used in system design and

cross-sys-tem comparisons MIPS describes the average

num-ber of machine instructions that a central

process-ing unit (CPU) performs per unit of time of 1

sec-ond This is a narrow definition of performance, as

many other factors influence overall speed and

effi-ciency The Digital VAX-ll/780 is defined as a

base-line at 1MIP By the late 1990s, most consumer

desk-top models delivered about 3 to 10 MIPS and

high-end minicomputers and mainframes ranged from 10

to 50 MIPS, with supercomputers comprising the top

ofwhatever was state ofthe art at any particular time

See benchmark

Mir A landmark "permanent" Earth-orbiting space

station used for observation, experimentation, and

scientific research about living and working in space

U.S and Russian Mir missions began early in 1995,

with the core module launched in February 1986 Mir

consisted of a number of connected modules,

dock-ing components, solar screens, life support systems,

and scientific instruments The Mir capsule could

hold two or three people fairly comfortably, and up

to six for short periods oftime Travellers to and from

Mir connected through the NASA space shuttle

Amateur radio enthusiasts enjoyed regularly

listen-ing to Mir signals, and some have sent transmissions

to the orbiting station

A great deal was learned about the wonders and

chal-lenges of livinginspace from Mir Information and

photographs related to Mir missions can be seen

through the Office of Space Flight Web site

After orbiting the Earth for more than 15 years, the

space station entered the Earth's atmosphere, in a

controlled decline, on March 23, 2001

http://www.nasa.gov/osf/mir MIR See multimedia information retrieval mirror Ahighly reflective, usually polished surface that readily reflects light while absorbing very little

of it Water and glass have mirroring qualities, but some ofthe light is refracted or absorbed, making the image foggy or ghostly rather than crisp and detailed Highly polished metal and silvered glass make ex-cellent mirror surfaces Dielectric mirrors are most effective within a narrow range of wavelengths and angles of incidence

Mirrors were used for line-of-sight signaling long before electrical telecommunications methods were available Hikers still regularly carry them for emer-gency signaling in the wilderness Mirrors are also used in many types of computer devices, especially those which incorporate laser beams, such as laser printers The mirror serves to direct the beam inside the mechanism onto the appropriate areas, such as a printing drum

In fiber optics, it was discovered by MIT scientists that dielectric films would behave more like a metal

if they were layered in a particular way, a capability that they subsequently applied to the development of improved lightguides that had the potential to sup-port the transmission ofa wide range ofoptical wave-lengths, while retaining the polarity of the transmit-ted beams The new technology, described in 2000, was also capable ofreflecting light through small ar-eas for incrar-eased miniaturization See coaxial omniguide, heliograph

mirroring A means of providing system backup se-curity or redundant access by replicating data in dif-ferent locations The system can enable the user to access the mirror location if the original data storage location becomes oversubscribed or corrupted Or, the system can be restored with information from the mirror Redundancy is a very common property of computer systems Some will mirror whole directory structures and files as a matter of course Some hard drive systems are set up to constantly mirror infor-mation over several devices While mirroring almost inevitably costs a little more in terms of memory or storage space and in processing time, itis usually worthwhile See mirror site, RAID

MISSee Management Information Services missile, fiber-guided Aguided missile that flies in a high trajectory with a camera housed in its nose, which is connected to the launcher by a fine spool-ing fiber optic cable The cable enables a remote hu-man pilot to view the progress ofthe flight and guide

it to targets within a 10-mile range using a joystick

as the guidance controller This weapon was initially released in the early 1990s by the U.S Army as the FOG-M (Fiber Optic Guided Missile) but not widely fielded See multiplexed optical scanner technology MITS Micro Instrumentation and Telemetry Sys-tems The historic creators of the Altair microcom-puter, MITS, under the direction ofEd Roberts, origi-nally sold radio transmitters (telemetry devices) for model planes These products did quite well and got

moved into the area of calculator kits, there was a lot

of competition from bigger names like Texas

Instru-ments, and the Altair was in essence an effort to stave

off bankruptcy MITS developed the MITS 816 in

1972, and later the historic kit for the Altair 8800 in

1974 While the Altair is not the first microcomputer,

it is to be credited as the first commercially

success-ful microcomputer In spite of the success of the

Al-tair, the company was sold to Pertec, a manufacturer

of peripherals See Altair, Intel MCS-4, Kenbak-l,

Mark-8, Micral, Scelbi

MJ modular jack Any jack designed to interconnect

readily with various standardized receptacles in a

cir-cuit system See RJ

MLPPmultilevel precedence and preemption (e.g.,

as in ISDN Q.85 and A.735 community of interest

services)

MMC 1 minimum monthly charge 2 See Mobile

Multimedia Communication project 3 See

MultiMediaCard

MMCA See MultiMediaCard Association

MMCFSee Multimedia Communications Forum

MMCXSee Multimedia Communication Exchange

MMDC 1 See Massachusetts Microprocessor

De-sign Center 2 See Multi-Media and Digital

Commu-nications lab 3 See Multi-Service, Multi-Carrier,

Distributed Communications 4 See multimedia

desktop collaboration 5 See Multimedia

Develop-ment Center 6 See multimodel data compression

7 See Multiple Module Data Computer

MMDM See micromachined membrane deformable

mirrors

MMDSSee microwave multipoint distribution

sys-tem

MME 1 See Microsoft Mobile Explorer 2 See

Mobile Meteorological Equipment 3 See

Multime-dia Message Entity

MMF 1 See Mobile Management Forum 2 See

multimode optical fiber

MMI machine-to-machine interface Since this can

easily be confused with the abbreviation for

man-machine interface, which was also traditionally MMI,

it is preferable to use HMI for human-machine

inter-face

MMICSee Monolithic Microwave Integrated

Cir-cuit

MMMSee multimedia mail

MMMSSee Multimedia Mail Service

MMMSecSee Multimedia Mail Security

MMS1 marketing measurement system 2 memory

management system 3 meteorological measurement

system.4.module management system.5.

multime-dia survey

MMSI1 Manchester Museum of Science &

Indus-try.2 See Maritime Mobile Service Identity

MMSPSee modular multi-satellite preprocessor

MMSSMaritime Mobile-Satellite Service

MMTA See Multimedia Telecommunications

Asso-ciation

MMU1 Manned Maneuvering Unit A human

ma-neuvering unit used in untethered space walks

2 memory management unit Computer circuitry of-ten built into central processing chips to handle ad-ministration of blocks of storage

MMUSICSee Multiparty Multimedia Session Con-trol

MMX Multimedia Extension Matrix Math Exten-sion See Pentium MMX

MNLPSee Mobile Network Location Protocol MNP See Microcom Networking Protocol

MNRP Mobile Network Registration Protocol mobile assisted handoffMAHO.Aprocess in which the handoff of a voice channel by a mobile station is assisted by the base station by providing information

on the surrounding radio frequency (RF) signal en-vironment

Mobile Broadband SystemMBS Awireless cellu-lar network developed as one ofthe European RACE

II Integrated Broadband Communications (IBC) projects The purpose of the project was~odevelop third-generation, integrated mobile systems as part

of a universal, cost-efficient, voice/data personal communications system

MBS transparently transports Asynchronous Trans-fer Mode (ArM) cells over the air interface at 60 GHz

at data rates up to 34 Mbps (with higher rates pos-sible through multicarrier transmission) Two recom-mended sub-band frequencies for MBS are 62 to 63 GHz and 65 to 66 GHz

MBS is supported over B-ISDN systems and differs from traditional cellular by its bursty nature and dy-namically adjusting data transmission rates A new channel structure and protocols have been developed

in conjunction with the project to exploit the packet characteristics of B-ISDN connections See Inte-grated Broadband System, Research into Advanced Communications in Europe

Mobile Data Base StationMDBS In CDPD mobile communications, a system which provides data packet relay functions between the Mobile End tem (M-ES) and the Mobile Data Intermediate Sys-tem (MD-IS) See Cellular Digital Packet Data Mobile Data Intermediate System MD-IS In CDPD mobile communications, a system which pro-vides routing and location management functions, utilizing a Home Domain Directory (HOD) database The MD-IS communicates with the Mobile End Sys-tem (M-ES) through the Mobile Data Base Station (MDBS) See Cellular Digital Packet Data

Mobile End SystemM-ES In CDPD mobile com-munications, the system through which the subscriber accesses wireless network services M-ESs include modems installed in laptops, palmtops, personal digi-tal assistants (PDAs), etc See Cellular Digidigi-tal Packet Data

Mobile Identification NumberMIN Each wireless phone is assigned an identification number by the carrier The MIN is not attached to the individual, as the phone may change hands or the individual may change locations

Mobile Information Device ProfileMIDP A speci-fication supported by a number of major wireless