Fiber Optics Illustrated Dictionary - Part 65 docx

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 couldcause backreflection (top). The joint must be firmly secured within a sturdy supporting structure (e.g., the Corning Cable Systems CamSplice™) to maintain theposition ofthefilaments relative to one another (bottom). Mechanicalsplicingis onlyrecommended for joints that are well protected from strain and temporary joints such as patch panels that require frequent re- configuration. Forpermanentsplices, fusion splicing is generallypreferred. 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 alist or table of MAC addresses which may be static or dynamic. Dynamic MAC address lists may be updated in a variety of ways depending on the stability of the configuration ofa network and the size ofa network. The MAC address is used by a network bridge to determine whether a packet is to be forwarded. By copy- ing an incoming source address to a MAC address table, the bridge builds up aport-related"picture" of device locations on the network. Since there are usually efficiency trade-offs on large networks, with machines being added and removed and MAC address tables becoming large and unwieldy, certain balancing mechanisms are built into bridge management. By limiting the lifespan ofa MAC address, the system can be tuned to best serve the needs of the network. Thus, a dynamic MAC address that 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 a static MAC address that isn't automatically deleted. MediaAccess Exchange MAX. A system-level network access unit from Ascend Communications, into which peripheral cards can be inserted. A MAX can support multiple host ports or direct network connections, videoconferencing units, and remote LAN connections. MediaAccess Project MAP. An important nonprofit, public interest telecommunications law firm that looks out for the First Amendment rights of individuals 632 before the legal system and the Federal Communi- cations Commission (FCC). Over the years, broadcast agencies have been provided free use of the airwaves and, in return, have a legal responsibility to provide aportion of programming 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 of the 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/ MediaAccess Unit MAU. In Token-Ring local area networks (LAN s), a wiring concentrator that connects the end stations. The AU provides an interface between the Token-Ring router interface and the end stations. Also known as Access Unit (AU). See Multistation Access Unit. Media Interface Connector MIC. An eight-pin modular RJ-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 recommended for audio-visual applications by DAVIC specifications. medium Earth orbit MEO. An orbiting region around the Earth into which certain types of communications satellites are launched, mid-way between low and high Earth orbits into which geostationary satellites are typically launched. The lifespans of medium-orbit satellites are about 10 to 12 years. Most medium-orbit satellites travel about 10,000 to 15,000 km outside Earth. A region called the Van Allen radiation 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. MeetMeA commercial 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 conference in progress with an Add On conference. 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 Trunk Telecommunication trunks 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 10 6 or 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 of these uses is in descriptions of computer storage capacity as megabytes (MBytes), in which 1 MByte is 1,048,576 bits. See kilo Megaco ProtocolA network media gateway control protocol used between elements of a physically © 2003 by CRC Press LLC decomposed multimedia gateway, that is, between a Media Gateway and a Media Gateway Controller. The Protocol was submitted as a Standards Track RFC by Cuervo et a1. in November 2000. It provides a general framework suitable for gateways, multipoint 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. meggerAn instrument for measuring values of very high resistance used, for example, for insulation resistance testing. See Wheatstone bridge. Melissa See virus. Melles GriotlasersA line of lasers from the Melles Griot optical company. The firm is a leading supplier of gas 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 announced acquisition of the Laser Power Microlaser Group, developers of blue, green, and near-infrared solid-stated diode-pumped lasers. Melpar model An 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" ofa 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. meltback In fusion splicing of fiber and other materials, the receding away from the point where the fusion joint will occur. Machines that perform automated 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 different distances depending upon their diameter, com- position, and environmental conditions. meltback test In automated fusion splicing, a preliminary 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 be consistent, causing varying degrees of meltback. 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. memory In 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 of the most basic elements ofa computing 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 computers to provide basic nonvolatile operating param- eters to a system, particularly on startup. In the earliest microcomputers, a programming language was sometimes included in ROM. Random access memory (RAM) is dynamically allocated py the system and applications programs. RAM is further distinguished 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 typically operates at about 60 to 80 ns, although this may change as newer, faster types of memory are developed. Most types of computer chip memory are volatile, that is, the contents will disappear if the system is not constantly powered and refreshed. However, there are some types of chips that can retain information, such as erasable, programmable, read-only memory (EPROM) chips. The price of memory fluctuates dramatically. In 1986, 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 another round of buying. In 1978, the TRS-80 computer ran with 4 Kbytes of memory, and with 8 Kbytes it could do word processing and spreadsheet applications quite well. By the mid-1980s, the Amiga computer could multi task and run graphics programs con- currently with stereo sound quite comfortably in 4 Mbytes of RAM. Systems in the late 1990s rarely ran efficiently with less than 16 Mbytes, and most vendors recommended 32. Computers now commonly come installed with 256 MBytes or more. MEMS See micro-electromechanical system. Mensa Single Fiber Supertrunk SystemA commer- ciallinear, synchronous, high bandwidth, point-to- point optical transceiver system designed specifically for supertrunk applications, distributed by Synchro- nous. It may 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 photo detector. The system provides dual-trunk performance over a 633 © 2003 by CRC Press LLC 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 standard 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 vapor 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 A type ofcircular network backbone topology in which data can travel back along the backbone ifa node becomes unavailable due to a disruption, 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 several nodes away. Some vendors and users prefer this over a ring topology as more than one route can lead to aparticular location on the network. See topology. message circuit noise On a correctly terminated circuit 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 determine 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 communications, most data networks do not need to establish 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 proofof origin; nonrepudiation with proofof delivery. MSP is a content protocol, in the application layer, and is implemented within originator and recipient MSP user agents. It is 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. An XAOO message comprises a content and an enve- lope. With MSP, a new message content type is defined 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, in turn, is signed by a certification 634 authority (CA). The CA manages X.509 certificates and Certificate Revocation lists. message switching A means ofswitching and multiplexing 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 communications 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 vapor lasers to make them more efficient without requir- ing increasingly complex or unwieldy tubes. Voltage is transmitted through a choke coil (10), a charging diode (ll), anda charging resistor (13) into the storage capacitor (12). The switching device (14) stimulates the capacitor to discharge its stored power into the circuit in the form of a preliminary charge between the cathode (2) and the grid (4) which provides variable impedance. This triggers the main discharge between the cathode and anode (3). The grid also serves as a discharge "buffer, " improvingthe life- time of the componellt. [US. patent#6,229,837, May 2001.} metal vapor laser A type of atomic gas laser that efficiently 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 as A. Ozu have proposed variations that enable higher efficiency with a grid electrode placed near the electron-generating cathode to provide a preliminary discharge. © 2003 by CRC Press LLC The Institute of Physics developed the first Bulgar- 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 of Ethernet 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. METEOSAT Meteorology satellite. meter A 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 of length (e.g., yard) except in scientific circles, where metric is used. Metropolitan Area Network MAN. An urban network of high-speed hosts. See MAE East, MAE West, SMDS. Metropolitan Fiber Systems MFS. 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 ServiceArea MSA. 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 residents within the counties encompassing these areas. The Federal Communications Commission (FCC) has used this census designation to recognize over 300 MSAs for the purposes of assigning telecommunications licenses such as cellular telephone licenses. See Rural Service Area. Meucci, Antonio An 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 credited as to their impact on subsequent inventions such as telegraphs and telephones, which made telecommunications history. Meucci developed rheostats, electroplating techniques, and experimented with passing electricity through the human body. While studying mild electrical charges, he discovered the "electrophonic" effect, which related nerve responses to specific applications 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 of the earliest telephone-like mechanisms. He emigrated from Cuba to the u.s. and applied for a caveat for his teletrofono which 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 Gray) may have had access to papers describing Meucci's invention and, due to greater resources and celebrity, overshadowed his inventions. See telephone history. MeyercodeA flag 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. MFJ See Modified Final Judgment. MFS See Metropolitan Fiber Systems. MFSK See multiple frequency shift keying. MH See Modified Huffman. mhoApractical unit of the 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 interferometer See interferometer. Micral The first fully assembled 8008-based microcomputer, 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 introduced 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-electromechanicalsystem MEMS. Technol- ogy for integrating electromechanical functions into integrated circuits. MEMS-based actuators are used in single- and multimode fiber optic switches. microbend In 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 optical transmissions path as the light "bounces" through the fiber, but are not likely to significantly degrade the signal. However, if the fiber is especially slim or the wavelengths especially long, microbend losses may occur. If there are a large number of microbends, the accumulated effect of the disruption over distance, especially in a cable with a small core radius, may be significant. See loss, macrobend, macrobend loss. MicroCal Module A new type of integrated circuit (IC) designed to facilitate self-monitoring in virtu- ally any type ofwireless 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 acentral mainte- nance center. The module, designed by Micronetics Wireless, was awarded a u.s. patent in 1996. Micronetics is working with anumber ofcompanies, including Nortel and Motorola, to integrate the module into wireless infrastructure equipment. Microcom Networking Protocol MNP. Aseries of proprietary error control and data compression protocols designed for dialup modems, which are often 635 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary used in conjunction with industry standard ITU- T- recommended error control mechanisms. For example, MNP-4 works with modems that transmit at data rates up to 14,400 bps. MNP-4 is often implemented in conjunction with the VA2 error control 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-carrying plastic for storing scanned printed matter, especially newspapers, books, journals, etc. Since microfiche information is miniaturized to fit as much data on asheet 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 information, 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 ofstorage 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 ofcurrent through actuators incorporated 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 Adevice for apprehending sounds and transmitting them electrically or acoustically to a receiver or audience. A very simple microphone can be created by wrapping stiffpaper 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 electronics 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 computers 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 of Popular Electronics, so he and Gates talked about it in Harvard Square, and con- ceived the idea of writing 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 interpreters for various languages based on their business ac- tivities together through high school, and 8K BASICs Microcom Networking Protocols Name Notes 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. 636 © 2003 by CRC Press LLC were available for the PDP-8. They developed the BASIC in a simulation environment, since it wasn't practical to write it on 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 coding it, 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 software, 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-off development period and environment. This first BASIC was later ported to many machines. Not long after the Altair kicked off the microcomputer 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 systems, 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 warehousing applications. Microsoft Data Warehousing Alliance DWA, MDWA. A trade association for those using and supporting Microsoft Data Warehousing Framework information technology (IT) applications and standards. Microsoft Incorporated One 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 during 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. Paul Allen learned of the Altair computer in a Popular Electronics article he saw in Harvard Square. Since the Altair so closely paralleled an earlier microcomputer 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 Davidoff created 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 Sun downer 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 development, the primary focus of the company has been software, and a substantial portion of the rev- enues are derived from operating systems and business-related applications. Paul Allen left the company to invest in a number ofother 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 began 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 of president and CEO. Gates continued as chairman and chief software architect. See Allen, Paul; Altair; Gates, William; MITS; Traf-O-Data. Microsoft Mobile Explorer MME. A multi standard microbrowser emulation environment optimized for low-resource devices such as mobile telephones capable of displaying HTML-like markup language pages. See browser, PDA microbrowser. microwave A radio wave transmission frequency (1000+ MHz) generally used for radar and radio re- peaters. Microwaves also provide the cooking power 637 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary for microwave or radar range ovens. The generation of microwaves was initially achieved with magnetrons 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 between 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 developed into cavity magnetrons and traveling-wave tubes. Microwave generators and relays are now an important aspect of satellite 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 constructed from mesh orsolid materials are usedfor very short (microwave) radio waves. The curvature of the dish and the relatedplace- ment of transmitting orreceivinghorns are important to the quality of the signal transmitted or received. [Classic Concepts photos; used with permission.} microwave antenna Due to the very short wavelengths 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 traditional television and radio broadcast waves. The 638 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 ofa parabolic dish antenna is a multiple 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 antenna, 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 satellite to the local transceiver, and broadcast from there to subscribers within about a 50-mile radius, depending 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 programs. The MMDS system is in the process of chang- ing from analog to digital technology, opening up op- portunities for digital multiplexing through highly linear radio frequency (RF) subsystems, thus providing more television channel choices for viewers. microwave radar Radar systems employing microwaves have been extremely important in navigation, tracking, surveillance, guidance, and communications systems. Much of the early research in microwave radar was conducted at the Massachusetts lnstitute of Technology (MIT) radiation laboratory in the early 1940s. Mid-Span Meet An interconnection point between two co-carriers. The Mid-Span Meet is the point up to which the carriers provide cabling and transmissions. MIDI See Musical Instrument Digital Interface. MIDI time codeMTC.A standard developed to iden- tify timing information associated with a stream of Musical Instrument Digital Interface (MIDI) data. See SMPTE time code. MIDP See Mobile Information Device Profile. Midwestern Higher Education Commission MHEC. MHEC was founded as an interstate agency in 1991 to promote resource sharing in higher education. As a subgroup, it includes a Telecommunica- tions Committee that takes a regional approach to improving access, services, and costs of telecommunications services. © 2003 by CRC Press LLC Milan Declaration on Communication and Hu- man Rights This declaration was put forth in 1998, based in part on a number of global 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 Beij ing Platform of Action, and other important ac- knowledgments of human rights. The Declaration asserts the intrinsic relationship between freedom of opinion and expression and the technologies and venues available for their communication. It declares 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 of rapidly chang- ing information and communication technologies, " It affirms the need for equitable access to all communications media coupled with the mandate to pre- serve and sustain cultural rights and diversity. It un- derlines the importance of not reducing all information users to the category of consumers and affirms their role as communications producers and contribu- tors. It calls for international recognition of community broadcasting as a vital contributor to human freedoms. 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 Streetplant This 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 similar AC power suppliers followed its example. milli- (abbrev. - m) An SI unit prefix for 1 thousandth, 10- 3 or 0.001. Thus, a milliamp is 1 thousandth of an ampere. MILNET Military Net. The ARPANET was a historic 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 geostationary 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 communications from terminal to terminal, anywhere on Earth. By transmitting from satellite to satellite, ground hops are reduced and security heightened. Milstar terminals provide a variety of data services, including voice, data, facsimile, or teletype communications. MIME See Multipurpose Internet Mail Extension. MIN See Mobile Identification Number. Miner, Jay ( 1930-1994) Agifted design engineer responsible for designing the hardware for the Atari 800 computer, the Amiga computer, and the Lynx color handheld game machine. In 1982, Miner joined Hi Toro to develop the Lorraine computer, which was subsequently sold as the Amiga by Commodore Busi- ness Machines. A proponent of open-mindedness and creativity, Miner included his dog's pawprint inside the case of the Amiga 1000. After the Amiga, he created the Atari Lynx, a fast color handheld game machine. Jay Miner was affectionately known as Padre, the Father of the Amiga, to the computing community. 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 creation. 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, particularly for graphics and sound, is a tribute to its efficient and insightful design. See Amiga computer, Commodore Business Machines. minifloppy A 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 of storage on these high capacity floppies is substantially cheaper, and they may, in time, supersede current floppies. minimal shift keying MSK. 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 modulation, phase shift keying. minimize button,iconize button Graphical user in- terfaces on several different operating systems include 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. Ministeredes Postes etTelecommunicaciones The telecommunications authority for the Democratic and Popular Republic of Algeria. Online communications are in French. Ministerio de Comunicaciones The telecommunications planning and regulatory authority of the Re- public of Columbia in South America. http://www.mincomunicaciones.gov.co/ Ministry of Information Technology and Telecom- munications MITT. The Mauritius ministry that handles the formulation and implementation of 639 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary government policies in telecommunications and information 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 radio station and operator licenses, monitors and inspects stations and radio frequencies, and sets technical standards for radio equipment. http://mpt.go.jp/ Ministry of Telecommunications The telecommunications authority of the Lebanese Republic under the direction of the Minister of Post and Telecommu- nications. http://www.mpt.gov.lb/ Ministry of Telecommunications and E-Com- merce The authority in Bermuda that oversees telecommunications, broadcasting, and frequency administration. http://www.mtec.bml MinitelA French 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. MIP See Multichannel Interface Processor. MIPG See Multiple-Image Portable Graphics. MIPS million instructions per second. A measure of processor speed used in system design and cross-system comparisons. MIPS describes the average number ofmachine instructions that a central processing unit (CPU) performs per unit of time of 1 second. This is a narrow definition of performance, as many other factors influence overall speed and efficiency. The Digital VAX-ll/780 is defined as a base- line at 1 MIP. By the late 1990s, most consumer desktop models delivered about 3 to 10 MIPS and high- end minicomputers and mainframes ranged from 10 to 50 MIPS, with supercomputers comprising the top of whatever was state of the 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 ofa 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 of time. 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 living in space 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 640 controlled decline, on March 23, 2001. http://www.nasa.gov /osf/mir MIR See multimedia information retrieval. mirror A highly reflective, usually polished surface that readily reflects light while absorbing very little of it. Water and glass have mirroring qualities, but some of the 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 emergency 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 support the transmission ofa wide range of optical wavelengths, while retaining the polarity of the transmitted beams. The new technology, described in 2000, was also capable of reflecting light through small areas for increased miniaturization. See coaxial omniguide, heliograph. mirroring A means of providing system backup security or redundant access by replicating data in different 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 information over several devices. While mirroring almost inevitably costs a little more in terms of memory or storage space and in processing time, it is usually worthwhile. See mirror site, RAID. MIS See Management Information Services. missile, fiber-guided A guided 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 human pilot to view the progress of the flight and guide it to targets within a 10-mile range using ajoystick 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 microcomputer, MITS, under the direction of Ed Roberts, origi- nally sold radio transmitters (telemetry devices) for model planes. These products did quite well and got © 2003 by CRC Press LLC the company under way, but when the company moved into the area ofcalculator kits, there was a lot ofcompetition 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 successful microcomputer. In spite of the success of the Al- tair, the company was sold to Pertec, amanufacturer 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- cui t system. See RJ. MLPP multilevel 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. MMCF See Multimedia Communications Forum. MMCX See 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. MMDS See microwave multipoint distribution system. 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 interface. MMIC See Monolithic Microwave Integrated Cir- cuit. MMM See multimedia mail. MMMS See Multimedia Mail Service. MMMSec See Multimedia Mail Security. MMS 1. marketing measurement system. 2. memory management system. 3. meteorological measurement system. 4. module management system. 5. multimedia survey. MMSI 1. Manchester Museum ofScience & Indus- try. 2. See Maritime Mobile Service Identity. MMSP See modular multi-satellite preprocessor. MMSS Maritime Mobile-Satellite Service. MMTA See Multimedia Telecommunications Asso- ciation. MMU 1. Manned Maneuvering Unit. A human maneuvering unit used in untethered space walks originating from the u.S. space shuttle missions. 2. memory management unit. Computer circuitry often built into central processing chips to handle administration ofblocks of storage. MMUSIC See Multiparty Multimedia Session Con- trol. MMX Multimedia Extension. Matrix Math Exten- sion. See Pentium MMX. MNLP See Mobile Network Location Protocol. MNP See Microcom Networking Protocol. MNRP Mobile Network Registration Protocol. mobile assisted handoffMAHO. A process 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 environment. Mobile Broadband System MBS. Awireless cellular network developed as one of the European RACE II Integrated Broadband Communications (IBC) proj ects. The purpose of the proj ect was ~o develop 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 possible through multicarrier transmission). Two recommended 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 dynamically 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. MobileDataBaseStation MDBS. In CDPD mobile communications, a system which provides data packet relay functions between the Mobile End Sys- 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 provides 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 System M-ES. In CDPD mobile communications, the system through which the subscriber accesses wireless network services. M-ESs include modems installed in laptops, palmtops, personal digital assistants (PDAs), etc. See Cellular Digital Packet Data. Mobile Identification Number MIN. 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 Profile MIDP. Aspeci- fication supported by a number of major wireless 641 © 2003 by CRC Press LLC . Press LLC Fiber Optics Illustrated Dictionary used in conjunction with industry standard ITU- T- recommended error control mechanisms. For example, MNP-4 works with modems that transmit at data rates up to 14,400 bps. MNP-4 is often implemented in conjunction with the VA2 error control protocol. Mach Zehnder. The receiver is based upon a high-response PIN photo detector. The system provides dual-trunk performance over a 633 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary single optical fiber linle For. computers. See Altair, Kenbak-I, Mark-8, MITS, Scelbi-8H, Simon, SPHERE. micro-electromechanicalsystem MEMS. Technol- ogy for integrating electromechanical functions into integrated circuits. MEMS-based actuators are used in single- and multimode

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