Fiber Optics Illustrated Dictionary demarcate the end of one communication or section and the beginning of the next one, especially in situ- ations where many people are sending information through the same queue, such as aprint queue or (2) to identify the type of communication or the person to whom it belongs. bantam tube A squat electron tube with a normal- sized base that was once commonly used in small ap- pliances or battery-operated mobile devices like por- table radios. Modem transistors have since made most types of vacuum tubes obsolete. See acorn tube. bar code Identification, information, and manage- ment code designed for optical scanning by a read- ing device. Black and white visual bar codes are fa- miliar identifiers on consumer products. They assist the checkers in entering prices and adjusting inven- tory databases. Bar codes are frequently inserted on postal letters and packages that have been optically interpreted. In fact, the information encoded into video and audio discs is stored via bar codes. Bantam portA connecting interface used on Tl sys- tems for interfacing with receive and transmit (e.g., DS 1 inlout) or external timing sources, typically with balanced 100- or 120-ohm termination. Amini-Ban- tam may be used on T1 daughtercards for support- ing an external monitor. In circuit testing, the sleeve on the Bantam connection may be used to ground the circuit. Port Configurations - Bantam Unlike RJ-45 (left) orbayonet-mountports (middle), which have distinctive shapes, aBantam port is very simple and unassuming, just a small round hole (or dual holesfor receive and transmit connections). bar generator A device used to generate horizontal or vertical bars on an output device to determine and adjust linearity. Baran, Paul (ca. 1926- ) A Polish-born American engineer, Baran is acknowledged as a significant In- ternet pioneer. He conceived a Distributive Adaptive Message Block Network (a concept dubbed packet switching by Donald Davies) while working at RAND Corporation on U.S. federal communications infrastructure projects. The core concept was to cre- ate a decentralized system through which data could flow in any direction such that ifa part of the system were lost, a portion of the system and the data would survive. Baran worked briefly on the historic UNIVAC com- puter project before it was taken over by the RAND Corporation and, after jobs elsewhere, ended up at RAND. Baran's networking ideas were verbally pre- sented at RAND Briefing B-265 in the summer of 1961. He subsequently authored a series of memo- randa entitled "On Distributed Communications" which were released beginning in 1964. Around the 102 same time, Davies appears to have been indepen- dently developing distributed network concepts. In the analog electronics world of the 1960s, Baran's idea was a far-fetched proposal, far ahead of its time (it was rejected as impossible by AT&T). As digital technology evolved, however, Baran's ideas became a practical possibility and formed the essential inspi- ration and format for distributed networks that evolved into the Internet. A future-oriented thinker, Baran also predicted the e- commerce and online entertainment explosions of the year 2000, long before personal computers, the In- ternet, and the World Wide Web even existed. He pro- phetically described online comparison shopping from home through the use of product images and databases back in 1967. Baran founded a number of commercial ventures and co-founded the Institute for the Future. He is a trustee of the IEEE History Center. In April 200 1, Baran was awarded the Franklin Institute's Bower Award and Prize for Achievement in Science. See Davies, Donald; Internet. An oral history of Baran, transcribed in October 1999, is available online through the IEEE History Center. Barbe, Jane The actor and singer whose voice has been heard by millions as the telephone voice that informs subscribers about chan~ed numbers ("This number is no longer in service '), disconnects, and other situations. Barbe is heard on Bell and National Bureau of Standards systems and many national voicemail systems. She has provided the voice for Electronic Tele-Communications, Inc. 's Audichron time, temperature, and weather services since the mid-1960s. Fans of early television shows have seen her on the popular game show "I've Got a Secret" and "The Mike Douglas Show." Barclay box relayA historic telegraphic relay which had better sound amplification and portability than conventional models. Barclay insulator A type of early glass utility pole insulator invented by John C. Barclay. It is a type of spiral groove insulator and is numerically identified as CD 150. See insulator, utility pole. bare metal, down to the bare metal The essentials ofa machine or system. The low level systems func- tions. Programming "down to the bare metal" usu- ally means programming in assembly or machine lan- guage or hand-wiring a prototype breadboard. bare wire A wire without any kind of protective or insulating cover. The ends of insulated transmission wires are usually stripped of their covers to provide bare wire for a good electrical contact at a circuit junc- tion. Barge In A surcharge phone service or feature ofa multiline subscriber service enabling someone (hope- fully in authority) to barge into specified lines and interrupt a call in progress. It is a privilege that should not be used indiscriminately but may be important in emergency situations. See buttinsky. barge out To abruptly leave a call in progress. barium ferrite Barium, a silver-white, malleable substance which, in combination with iron, produces © 2003 by CRC Press LLC a substance that can be used in magnetic recording media. Methods of synthesizing barium ferrite nanoparticles through precipitation and spray pyroly- sis are being studied. Barkhausen, Heinrich Georg (1881-1956) A Ger- man physicist and educator, Barkhausen worked for Siemens & Halske and then accepted a professorship in communications engineering at the Dresden Tech- nical Academy in 1911. He founded the first global college for weak -current engineering, work that was fundamental to the evolution and application of elec- tron tube technology. Barkhausen discovered the Barkhausen effect in ferromagnetic materials and, in collaboration with K. Kurz, described Barkhausen- Kurz oscillations. See Barkhausen-Kurz tube. Barkhausen effectA phenomenon described in 1919 by H. Barkhausen when he was studying magnetic and acoustic effects. He observed that a slow, con- tinuous increase in the magnetic field applied to a fer- romagnetic material would result in discontinuous increases in magnetization due to changes in elemen- tary magnets in the increasing magnetic field. This suggested that magnetism was a phenomenon related to the larger domain ofa ferromagnetic substance as opposed to being a discretely atomic function. The effect was sufficiently strong to be heard as clicking sounds when amplified through a speaker. Barkhausen-Kurz oscillations In a vacuum tube, oscillation of electrons by means of electrodes and the grid through manipulation of the voltage across the grid and the plate such that the electrons flow back and forth between the filament and the plate. This phenomenon has practical applications for the gen- eration of ultra-high frequency waves and aided in developing the principles of velocity modulation. See Barkhausen-Kurz tube, electron tube, klystron. Barkhausen-Kurz tube, B-K tube A technology capable of generating microwaves that was developed around the same time as the magnetron, the Barkhausen-Kurz tube is a triode vacuum tube with the third element, the grid, operated at a high posi- tive voltage with the plate at zero or negative volt- age. This configuration produces an oscillating mo- tion of electrons between the filament and plate. The tube dates back to the work of German scientists H. Barkhausen and K. Kurz who described the technol- ogy in Physik Zeit V.21, 1920. By the mid-1930s, there were a number of commercial vendors of B-K tubes, which were used in research and military sens- ing applications. See Barkhausen, Heinrich Georg; Kurz, Karl; magnetron. barometerAn instrument designed to measure atmo- spheric pressure. It is one of the tools commonly used to evaluate and predict weather patterns. Barometers are incorporated into a number of other instruments as well, most notably traditional altimeters. Newer altimeters sometimes incorporate Global Positioning Service (GPS) capabilities. Barometers were important instruments in early stud- ies of magnetism, particularly in Italy where mem- bers of the Accademia del Cimento used barometers in the 1660s to provide an airless environment to study whether the attractive properties of various sub- stances were dependent upon air. Unfortunately, the difficulties of creating a vacuum and manipulating the materials within the small area hindered them !:~:!~\;~i;~:::~:::::~:S~::~:: :~:::l:~ •• early as the 1600s, in which a glow or flash appears above the mercury in a barometric tube if it is moved quickly or shaken. The phenomenon is similar to that exhibited by neon light, although this was not known at the time. See barometer. barreldistortionA type ofvisual aberration in which the outward comers of an image are contracted in- ward. This may happen on a convex or concave sur- face (depending upon whether it is backlit or frontlit) and is noticeable on older, more highly curved moni- tors and television screens. The opposite of barrel dis- tortion is pincushion distortion. See keystoning. barretter, barreter A device whose resistance changes in relation to temperature. The hot-wire barretter was devised in 1901 by R. Fessenden to improve the technology that was then being used to detect radio waves. The technology was incorporated into voltage-regulating devices consisting ofa wire filament connected to the circuit in series contained within a gaseous envelope. In conjunction with a waveguide, a barretter can be used to measure elec- tromagnetic power. BARRNet Bay Area Regional Research Network. An association ofuniversity campuses and government research centers in the San Francisco area. See BBN Planet. Bartholin, Rasmus (1625-1698) A Danish physicist and mathematician from the erudite medically in- clined Bartholin family, Bartholin followed the ex- ample of his father Caspar and brother Thomas and studied in Italy from 1653 to 1656. He is best known for his 1669 experiments with Ice- land spar, a transparent form of calcium carbonate with interesting birefringent properties. Bartholin published his findings as Erasmi Bartholini in Experimenta Crystalli Islandici Disdiaclastici and followed them up with other scientific publications that included information about optics. His was an important contribution, inspiring a number of other prominent scientists to study and mathematically de- scribe double refraction and its implications regard- ing our understanding of the nature of light. Bartholin (sometimes transcribed as Erasmus Bartholinus) had an interest in astronomy as well and described the path of a comet he observed in 1665, which is richly illustrated in Theatrum Cometum pub- lished in 1666. See Iceland spar, Nicol prism. Barton,Enos Melancthon (1840s-early 1900s) Bar- ton co-founded Western Electric with telegraph/tele- phone pioneer Elisha Gray. He initially fonned a part- nership in 1868 with George Shawk. Shawk rejected an offer to partner with Gray, but Barton was inter- ested in Gray's ideas and Gray & Barton was formed in 1869, evolving into the Western Electric Company in 1872. It is the spiritual forerunner of today's 103 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Lucent Technologies. Graybar Electric Company, Inc., was spun off from Gray & Barton in 1925 in order to provide electrical distribution. See Gray & Barton; Graybar Electric Company, Inc. base I. Bottom; lower support portion; portion to which something is bonded; substrate. 2. In utility pole insulators, the base may be smooth or may have drip points, little knobs for the distribution of stream- ing moisture. 3.In layered semiconductor fabrication, the beginning or bottom layer ofa component, which is often a supporting substrate. 4. In bipolar semicon- ductor components, a thin region of one type of semi- conductor sandwiched between an emitter and a col- lector of another type to form a dynamic environment. In the base region, excitable (highly mobile) electrons act as minority carriers moving between the emitter and collector. See p-njunction. 5. In chemistry, a sub- stance that gives up hydroxide ions in solution. base film Asubstrate for holding magnetic particles as in audio and video tapes. The materials used for base film vary but generally have the characteristics of flexibility, resistance to wear, and affinity for hold- ing the magnetic coatings that are applied to their sur- faces. Base Information Digital Distribution System BIDDS. A U.S. Air Force telephony communications distribution network installed in the 1980s with au- tomated functions such as directory and operator as- sistance, reporting, record-keeping, and billing. Base Information Transport System BITS. A U.S. Air Force military network system. Information about BITS is published on the Web as an aid to outside contractors planning and installing military informa- tion technology infrastructures. base insulator A large support and insulating struc- rure used on transmissions towers to insulate the tower from the ground. base memory jmgon The first block of memory, con- sisting of640 kilobytes, in the older Intel-based desk- top computers. Base memory is now more generally used to describe the typical or minimum memory with which a system is sold to the enduser. By early 2002, base memory configurations of 256 or 512 Mbytes wercommon. base rate I. The basic rate without options or value- added services. 2. The basic charge per minute for measured service. base station I. A main transmitting and/or receiving station or central switching station, often one which serves as a junction between wireless and wire line communications paths, or between broadcast signals and cable subscribers. 2. In mobile communications, a fixed station within the transceiver system. See cel- lular phone. 3.In Global Positioning Systems (GPS), areceiver established in a known location to provide reference data for differentially correcting rover files. Baseline data can be correlated with position data from unknown locations collected by roving receiv- ers to improve accuracy. baseband I. A simple type oftransmission in which the signal is sent without altering it, as by modula- tion, and which does not require demodulation 104 through modems to alter the signal at its destination. A transmission that is not segmented by frequency division (multiplexing). This basic signal is centered on or near the zero frequency. See sideband. 2. A one- channel or one carrier-frequency data network such as Ethernet, that is alternately shared by the various peripherals, such as computers and printers, or allo- cated as requested. See narrowband, Token-Ring. Contrast with broadband. baseband modem This phrase is an oxymoron, since a baseband signal is one that has not been modulated and thus doesn't require a modem to demodulate it. However, baseband modems do sometimes provide an interface device with some simple translation ca- pabilities and may physically resemble standard mo- dems, hence the name. Sometimes better termed a short haul modem, it is suitable for short distances. baseband repeater A common main station repeat- ing system used to retransmit a signal and, in some cases, drop out selected channel groups, e.g., voice channels, before retransmission. Over long distances with several legs, heterodyne repeating, which is less subject to loss or distortion from modulation and de- modulation, may be used in conjunction with base- band repeating to exploit the better properties of each method. See baseband, heterodyne repeater. baseboard raceway A cable conduit or pathway along wall baseboards. The raceway may run along the baseboards, or be built into them, so they won't be seen. Thus, wiring can be installed and hidden without tearing into the inner walls. baseline I. In coordinate systems, a scale, often the horizontal X axis, that establishes a reference struc- ture on which related data can be depicted. 2. In ra- dar, a line displayed to show the track ofa scanning beam. 3.In typography, an imaginary line extending through a font (horizontal in Roman and Cyrillic fonts) for alignment. Desktop publishing software is not entirely standardized; some programs treat the base- line as the bottom edge ofnondescending letters, and others treat it as the first unit beneath the bottom edge of these letters. 4. In a Global Positioning System (GPS), apair ofstations for which simultaneous data have been collected. bash, bash shell, Bourne-again shell A popular, powerful, practical sh-compatible Unix command interpreter shell (command environment) released in the late 1980s by the Free Software Foundation. Bash is based on the Bourne shell, with some features from Korn (ksh) and C (csh) shells. BASIC Beginner's All-purpose Symbolic Instruction Code. An English-like programming language de- signed at Dartmouth College in the early 1960s that evolved from the Dartmouth Simplified Code (Darsimco). BASIC was created to provide a pro- gramming environment that was faster and easier to learn than FORTRAN or lower level languages like assembler or machine code. BASIC was originally a compiled language that enabled students to write computer programs for the Dartmouth Time-Sharing System running on a General Electric (GE) main- frame computer. © 2003 by CRC Press LLC The availability and sophistication of commercial software has increased dramatically since the early days of BASIC and more powerful programming lan- guages have evolved (e.g., C/C++). Users no longer have to program a computer to use one, and the de- mand for fast, powerful software has necessitated the use of other languages. Thus, the original text-based BASIC has largely faded into computer history, sur- vived mainly by object-based graphical versions (pri- marily Visual BASIC) that are useful for writing utili- ties or prototyping software interfaces and software flow (e.g., proofof concept demonstrations). With so much off-the-shelf software now available, the mo- tivation for the general consumer to learn to program in BASIC has all but disappeared, though BASIC- like macro programming languages can still be found in most paint, database, and word processing pro- grams for the purpose ofautomating common tasks. See VisualBASIC. basic access authentication See authentication, ba- sic access. basic cable service The base service (lowest level) offered by atelevision cable company, consisting of a cable feed to the premises and broadcasting ofa spe- cific package of programs. The cable company's pro- gramming provisions, signals, and public, educa- tional, and government access channels are govern- ment regulated under the Cable Act. Rates for basic cable services and equipment are regulated by fran- chising authorities that are, in tum, certified by the Federal Communications Commission (FCC). FCC rules are available through the International Tran- scription Service (ITS). See Cable Act of 1984. Basic Call Model BCM. See Intelligent Networks Call Model. Basic Control System BCS. An interrupt-driven computer satellite control system. Basic Encoding Rules BER. Standardized rules for data encoding that provide support for the abstract syntax description language ofAbstract Syntax N 0- tation One (ASN.l). BER was developed in the 1980s, arising out of ISO X.409 and rewritten as ISO 8825 to provide a separation between ASN.l and BER concepts. It was then introduced in the 1988 CCITT Recommendations as X.209 and became a tool for use in the development of open systems architectures. It became one of three major schemes that evolved in the early 1990s for encoding and is strong in the areas ofextensibility and the ability to recognize encoding structure without knowledge of the originatingASN.l type. See Abstract Syntax N 0- tation One, Packed Encoding Rules, LightWeight Encoding Rules. Basic Exchange Radio Telecommunications Ser- vice BERTS. A system developed in the 1980s to pro- vide wireless services through radio signals to stan- dard local telephone loops, especially to rural areas or for emergency services. basic information unit BIU. In packet networking, aunit of data and control information consisting ofa request/response header (RR) and a following re- quest/response unit (RU). Basic Link A voice grade circuit providing certain specified standard levels for services, transmission, and loss (8 dB in the 300 to 3000 Hz bandwidth). See Assured Link. Basic Rate Interface BRI. There are two basic types of ISDN service available: BRI and PRI. BRI is an ISDN service consisting of two bidirectional 64 Kbps bearer channels (B channels) for voice and data and one delta channel (D channel) for signaling or packet networking at 16 Kbps or 64 Kbps. It requires two conductors through a U Loop, from the carrier to a terminator (NT 1) at the customer premises. Except in the rare cases ofextremely long phone lines with load coils, most existing phone lines can be used for BRI without significant changes to the actual wire. BRI is aimed at residential and small business users. See ISDN. basic sequential access method BSAM. A basic means of accessing data stored external to a proces- sor. Other common methods include basic direct ac- cess, and basic partitioned access. basic telecommunications AFederal Communica- tions Commission (FCC) general administrative cat- egory distinguished from enhanced service telecom- munications. The concept applies to telecommunica- tions that are facilitated by computer technologies without additional processing or protocol conver- sions. Basic phone service is one example. This ser- vice is regulated under Title II and mainly affects tele- phone service carriers rather than those offering en- hanced computer data services. As such, basic tele- communications providers may be subject to fees and regulations that don't apply to enhanced services pro- viders and are regulated in order not to stifle compe- tition with enhanced services providers. Providers offering both basic and enhanced communications services have to maintain distinctions between basic and enhanced services when billing clients and mar- keting services to potential customers. See Federal Communications Commission. Basic TradingArea BTA. An organizational desig- nation for wireless telecommunications in which the United States is subdivided into almost 500 basic trading areas (BTAs) which are collectively grouped into Metropolitan Trading Areas (MTAs). The BTAs are used by the Federal Communications Commis- sion (FCC) as a basis for assigning pes wireless phone system licenses. basket windingAtechnique of winding a wire coil, or other filamentous conducting material, such that the paths of the various turns of the winding do not touch except at junctions where they may cross. It is sometimes called lattice winding. Basket winding is used in applications where a long length of wire, or a greater degree of surface area, needs to be organized into a small amount of space. Basket wound antennas and other devices can be quite aesthetic, resembling arabesque. See basket-wound tuners. basket-wound tuners Historically, various types of basket winding with fine threadlike materials were commonly used in old radios to act as frequency 105 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary tuners. The windings were of many shapes, cylindri- cal, circular, somewhat spherical. They varied in com- plexity from a dozen turns or so, to many hundreds of turns, in intricate patterns in many layers. By vary- ing the shape, size, and the thickness of the wires, dif- ferent frequencies could be selected. A radio often came with a selection of basket-wound tuners with electrical contacts on the base that could be plugged in as needed. Basov, Nicolay Gennadiyevich (1922-2001) A Rus- sian medical assistant, physicist, and engineer, Basov made important contributions to the field of quantum radiophysics and pioneered ammonia-based beams (early laser research). By 1957, Basov was design- ing and constructing optical quantum oscillators that had potential for gas and semiconductor-based oscil- lators. By the early 1960s, along with various collabo- rators, Basov was creating injection semiconductor lasers with gallium arsenide. Through investigations of short laser pulses, high-power single-pulse Nd- glass lasers were developed in the mid- to late 1960s. In 1964, along with Townes and Prokhorov, Basov was awarded a Nobel Prize. Under Basov's guidance in the early 1970s, an original chemical laser was developed and Basov et al. described infrared laser stimulation of chemical reactions. See laser.; laser history; Townes, C. bass In audio, a low pitch; a deep audible tone. bat switch See toggle switch. batch An assortment of data or objects grouped to be processed during a single run ofa program or pro- cess. See batch file, batch processing. batch fIle A data file for grouping, storing, and fa- cilitating the execution of complex sequences or fre- quently used computer commands. Batch files are a convenient way to store configuration parameters, frequently used groups of commands, a list of appli- cations that are executed one after another, commands intended for deferred execution, scripts launched from Web pages, and startup commands for a com- puter system. ".BAT" is a familiar extension given to batch files on MS-DOS-compatible systems. Many systems provide job control languages (JCLs) or a va- riety of scripting languages for the quick creation of batch files. Perl is an excellent multiplatform pro- gramming tool for creating batch files use on and off the Web. Batch commands have traditionally been created with text editors, but graphical tools may be used. See batch, batch processing, JCL, Perl, Java. batch processing Deferred or off-line processing of an assortment of data, programs, or obj ects handled during a single program or process run. Unless there is a fault condition, batch processing usually assumes once the job is initiated, it will run undisturbed and unattended. Email is often handled as a batch process, e.g., your Internet Services Provider may wait a speci- fied period of time before posting a group of mes- sages to your account rather than posting each one as it is received. Payroll accounts are often run as batch processes, as are many data collection pro- grams, such as weather testing, astronomical obser- vations, etc. 106 It is not uncommon for batch processes to run as back- ground tasks, executing while users continue to use the system for other applications. Batch processes can be scheduled to run when network access is low, thus not putting a drain on system resources when many users are online. Batch processes can also be used to schedule transmissions, such as facsimiles, during hours when phone rates are low. See batch, batch file, realtime processing. Batch Simple Mail Transfer Protocol BSMTP, bSMTP, Batch SMTP. A batch version of the Simple Mail Transfer Protocol developed in the early 1980s by E. Alan Crosswell to facilitate the reliable trans- mission of electronic mail messages over distributed computer networks independent of the transmission subsystem. Batch SMTP allows a series of commands to be bundled and sent to a remote machine for ex- ecution' rather than establishing a typical interactive SMTP session. The processing of special characters may also be supported through batch processing. This protocol was presented to the BITNET community in 1982 and installed on many BITNET mailer gate- ways. See Simple Mail Transfer Protocol. See RFC 821, battery A group of two or more cells connected to- gether in such a way that they produce a direct elec- tric current (DC). While historians believe battery power may have been used for electroplating by the Parthians as early as the third century BC, the first significant records of modem battery experiments date from the work ofC. A. Volta. Battery-generated electricity was widely used in in- dustrial applications and telegraph and telephone communications in the early 1900s. Edison was a strong proponent of DC current and received much opposition from Tesla and Westinghouse, who were advocating alternating current (AC). Batteries are used widely in portable devices and as emergency or backup power for systems whose main power source is alternating current. The Sampling of the Evolution of Batteries chart describes a few com- mon batteries and interesting technological adapta- tions. See B Battery, cell, storage cell, talking battery. battery, rechargeableA direct current (DC) power source. A rechargeable battery is designed to readily have its power restored, usually through consumer- priced battery chargers or through an alternating cur- rent (AC) transformer attached between the wall socket and a battery-charging device. Rechargeable batteries are commonly used on palmtops, laptops, camcorders, etc. Most of them need to be fully dis- charged before being recharged, or a memory effect results in only a partial charge. Some can be trickle- charged when plugged into an outlet while being used. Larger rechargeable batteries for consumer electronics usually supply from two to five hours of charge. battery, storageA type of battery that, once charged, will hold that charge for a practical amount of time without constant electrical refreshes from another source, such as alternating current (AC). Car batter- ies are a type of common storage battery that are © 2003 by CRC Press LLC bazooka A device for isolating an outer conductor from other surfaces and connecting an unbalanced line to abalanced line. Bazookas are commonly used on the ends of coaxial cables that are to be connected to two-wire lines (e.g., copper twisted pair). See balun. BB 1. See baseband. 2. See broadband. BNC connectors are widely usedfor couplingfiber optic and coaxial cables to switchers and patch pan- els, as they provide a secure connection that is not easily uncoupled by bumping or tugging. End and overhead views of a number of common BNC (bayo- net mount) connectors are illustrated as follows: BNC to RCA plug (A), BNC to RCAjack (B), BNC to screw- type F connector (C), BNC to dual BNC male con- nectors (e.g., 'thin' Ethernet) (D), BNC terminator (E). E Dc BNC Connectors BA See ASCII; EBCDIC; Baudot, J.M. Emile. Bauschingereffect Straining a solid body beyond its yield strength in one direction decreases its yield strength in other directions. bay 1. Harbor, indentation, arced enclosure. 2. An opening in a rack or panel into which modular com- ponents can easily be inserted. Apatch bay has a se- ries of regular openings designed to securely hold modular components while still providing easy ac- cess, ease ofconfiguration, and swapping in and out as needed. See patch bay. 3. Part of an antenna array. bayonet baseA type ofjack or jack-like base, as on a bulb, which has a small projection on one side and slips into a receptacle with a turn so the proj ection catches within a small trough and secures the inserted object. bayonet nut connector, bayonet navy connector BNC. A quick-connect bayonet-locking connector, commonly used for coaxial cables for network or video transmissions. It is intended to provide a con- stant impedance. The outer shell has a sma,ll bayonet that inserts in a helical channel in the receptacle to aid in firmly securing and aligning the connector. This is good for securing connections that must not be in- terrupted or for securing cables against which there may be tension. See connector, F connector, RCA connector. recharged when the engine is running. They have a useful life of about three to five years if not com- pletely discharged too often (by leaving lights on, for example). Storage batteries are often used as backup systems for alternating current (AC) systems. See battery, fechargeable. battery backup A direct current (DC) backup sys- tem which kicks in if something happens to the pri- mary power system. For example, many phones now have memory storage for names and numbers, or ex- tra features like speakerphones or text display, that require more power than is provided by the current coming from the phone line. These phones may have a battery or AC power cord to help power the extra features which also functions as a backup battery to protect the contents of the electronic phonebook if the phone line power is interrupted by a power fail- ure, or if the phone is disconnected and moved from one location to another. Most computer systems have small batteries on the motherboard to protect the contents of certain types of chips that hold information such as configuration parameters. Lithium batteries are commonly used and should be replaced every 5 to 7 years or so. Many microwaves, clock radios, and VCRs have backup batteries so that the time is not lost during a power outage. If your appliance flashes 12:00 after a power failure, it probably doesn't have a backup battery. baud, baud rateA unit signifying a rate of trans mis- sion of data indicating the modulation rate, named after French engineer J.M.E. Baudot. The term is commonly used to describe modem data transfer rates (e.g., 9600 baud), although it originated from tele- graph signaling speed in the 1920s. Note that the rate of transmission is not necessarily equal to the rate of acquisition of the data. Line interference, handshak- ing' error correction, and other factors can cause the actual rate of data received to be less than the raw transmission speed associated with the amount of data transmitted. Baudot, J. M. Emile (1845-1903) A French engi- neer and inventor, Baudot made many contributions including a means, in the 1870s, to insert synchroni- zation signals between baseband signals so time di- vision multiplexing (TOM) could be used to combine signals into a bundle. He developed the Baudot code for telegraphic communications. Baudot code, Murray code A data code used in asynchronous transmissions, named for its inventor J. M. Emile Baudot. It was widely incorporated into teletypewriter communications beginning around 1870. Baudot code was based on a marks and spaces character-representation scheme employing five equal-length bits to symbolize upper case letters. A simple method of reversing the polarity of the line was in use for about half a century before it was su- perseded by frequency shift keying (FSK modulation techniques). The character set was very limited and eventually standard codes such as EBCDIC and ASCII superseded Baudot code except for special- ized communications, as fo~ the hearing impaired. 107 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary BBC 1. Broadband Bearer Capability. Abearer class field that is part of an initial address message. See ISDN. 2. See British Broadcasting Corporation. BBL 1. broadband loop. 2. BROADBANDLOOP Project. An ACTS project to define and test cost-ef- fective broadband access network concepts facilitat- ing the migration of fiber optic transmissions into local loops. The project demonstrates the upgrade of passive optical networks to high bandwidth capacity and the upgrade of wire-based networks to handle broadband services to the customer premises. The target group for the project is European residential subscribers and small- to medium-sized businesses. See BIDS, BONAPARTE, BOURBON, BROAD- BANDLOOP, UPGRADE, WOTAN. BBN Bolt, Beranek, and Newman, Inc. Ahigh-tech- nology company in Cambridge, MA which devel- oped, maintained, and operated the historically sig- nificant ARPANET and later the Internet gateway, CSNET CIC, and NSFnet NNSC. See BBN Planet. BBN Planet A subsidiary of Bolt, Beranek, and Newman, Inc., which operates a national Internet access network. See BBN. DBS See bulletin board system. DBT broadband technology. Dc See Committed Burst Size. BC 1. backward compatible 2. beam coupling. 3. bi- nary code. 4. broadcast. BCC 1. Bellcore Client Company. 2. See block check character. DCD See binary coded decimal. DCM See Basic Call Model. DCOB Broadband Connection-Oriented Bearer. In ATM networks, information in the SETUP message that indicates the type ofservice requested by the call- ing user. The appropriate bearer class depends on the Sampling of the Evolution of Batteries and Promising BatteryTechnologies Type Developer Notes B battery electrochemical N ogami et a1. Daniell battery J. F. Daniell Edison cell gravity/crowfoot cell Grove battery Abattery A chemical battery used in early telegraph systems, 1 volt. A variable storage nickel hydrate (positive) and iron oxide (negative) cell with an electromotive force lower than that ofa lead cell. This is a historic battery that was used in automobiles due to its ruggedness. A voltaic wet cell for providing small currents at a constant emf. Primary, 1.96 volts per cell. Zinc, platinum. Used by S. Morse. Historically used as talk batteries in telephone installations and as low voltage batteries for electron tube filaments. Modem versions are now commonly used for cameras, calculators, and other small portable appliances. Historical provider of low voltage power to the plates (anodes) in electron tubes and to communications relay circuits. Introduced in the early 1920s, C batteries provided bias voltage to electron tubes for the control of the grid circuit and were often used in conjunction with B batteries to extend the life of the B battery. C batteries are now commonly used with small portable devices such as flashlights and portable boomboxes. Announced by Bell in 1954, there are now a number of variations on this technology from different developers. Kyocera introduced a multicrystal silicon solar battery in 1996 that has a conversion efficiency rate of 17.1 %, considered good in the solar industry. A battery chemistry based on lithium polymer which may provide longer life for power-hungry mobile phones, laptops, etc. Biological systems in the form of synthetic melanins that appear to have the form of an amorphous semiconductor "threshold switch" operating at threshold significantly lower than inorganic thin films. These also exhibit electroluminescence at the point of switching energy states, described in 1973. Abattery with its electrodes immersed in an organic solvent electrolyte solution with the electromotive force generating by dopinglundoping processes associated with the electrodes, 1982. McGinness et al. Bell Labs organic C battery silicon solar lithium nouveau 108 © 2003 by CRC Press LLC specification of the network. BCOB-A (Type A) connection-oriented, con- stant bit rate, timing required BCOB-C (Type C) connection-oriented, variable bit rate, timing not required BCOB-X (Type X) transparentAAL, traffic type and timing requirements UNI 3.0 and UNI 3.1 must support Type A and Type C or Type X as a substitute for the first two types for virtual connections (VCs). Internet Protocol over ATM signaling must permit Type C and Type X bearer capability in specified combinations. Type C and Type X both apply to multiprotocol connections. BCP See Best Current Practice. BCRS See Bell Canada Relay Service. BCS 1. basic control system. 2. Batch Change Supplement. A development tracking system for documenting system features from proposal to fm- ished product. 3. See beam control system. 4. See Boston Computer Society. 5. See British Computer Society. BDF block data format, also referred to as data block format (DBF). Ageneric phrase for ablock ofdigital data with a specific format with respect to the size and order of the data items within the block. BDT See Telecommunications Development Bureau. Be 1. See burst size, excess. 2. See Be, Inc. Be, Inc. Acomputer software company founded by Jean-Louis Gassee, head of R&D at Apple Computer during the Apple II years. Be developed and released the BeOS (Be Operating System) in 1997. It is a fast, integrated-database, multiplatform OS aimed at the audio and graphics/video computer-using markets. In addition to BeOS, Be now provides integrated client- side software, development, and customization tools for Internet device and service providers and con- sumer electronics companies. In the early 2000s, Be was acquired by Palm. See BeOS. BE 1. base embossed. A designation for glass and ceramic utility pole insulators with embossings on the lower edge, usually of the size, company, and/or patent date. 2. Bose-Einstein. beacon 1. A signal, locator, or guidance beam or tone. 2. A transmitter that aids in monitoring radiant en- ergy propagation. beacon alert An alert frame in a Token-Ring or Fi- ber Distributed Data Interface (FDDI) device signal- ing a serious problem, such as a physical interrup- tion of the signal or Media Access Unit (MAU). The frame includes information on the location of the break or the station that is down. beam 1. n. A ray, shaft, or other directed energy or illumination, as an electron tube, radar, or light beam. 2. v. To direct or aim, as in a broadcast beam. beam antenna An antenna that transmits and/or re- ceives within a narrow, confined directional range. beam control system BCS. A means for directing a beam. It may also have control capability for turning a beam on and off. A BCS is usually used for di- recting common electromagnetic beams such as microwave radio signals or a beam of light, but it may also be used for high-precision control in atomic physics testing systems (e.g., study of neutrinos). The more sophisticated the technology, the more likely that beam control is automated with computer hard- ware and software. Logging of beam characteristics and activities over time may also be incorporated into aBCS. beam divergence 1. As a beam travels through the air, various factors may cause it to spread out. This divergence may result in attenuation or dispersion of the signal strength of a transmission over distance. 2. The path ofa beam may progressively move away from the axis of the original trajectory, resulting in divergence. beam position monitor BPM. A mechanism for keeping track of the position of an emitted/transmit- ted beam of light (e.g., laser light) or other electro- magnetic energy (e.g., radio waves). A beam position monitor is commonly used in systems where the di- rection of the beam can be controlled. beam power tube An electron tube with a beam that is directed and concentrated in certain specific direc- tions by a special electrode. Used, for example, in radio frequency (RF) transmitters. beam splitter A device that produces two or more separate beams from one incident beam. Mirrors and prisms are commonly used to direct or split light beams. Coherent laser light is favored for most beam splitting applications. Once the beam is split, the split beams are usually of a lower intensity than the origi- nal beam, in proportion to how many times the beam has been split. Beam splitting is used in a number of industrial instruments and consumer devices and is also used for testing and diagnostic purposes. In interferometers, a beam is split into two or more beams in order to compare the relationship of the beams when they are recombined. The interference patterns from the beams can provide information on influences from heat, vibrations, gases, etc. bearer channel See B channel. beat Short percussive tone, one instance ofarepeti- tive sequence, a reaction from the impact of one ob- ject or process on another, the interaction of two dif- ferent frequencies when certain portions of their cycles interact. See beat frequency, beat reception, zero beat. beat frequency The frequency resulting when two different frequencies beat together on anonlinear cir- cuit. The beat frequency is equal to the difference between the two separate frequencies, typically ex- pressed in cycles persecond (hertz). When the beats are very close to the same frequencies, they can be set to generate an audible tone which may change when subjected to the influence ofmagnetic materi- als. See heterodyne. beat frequency oscillator BFO. Alow-current gen- erator ofbeat frequencies in anonlinear circuit. BFOs are used in a number of practical applications from metal detectors, which use search and reference os- cillators, to older single sideband radio receivers. beat reception The combining of two different fre- quencies, usually the external, incoming frequency, 109 :?!. :1 : © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary and an internally generated frequency which are then easier to amplify or othelWise condition as a single frequency than the incoming frequency would be by itself: See heterodyne. For contrast, see zero beat re- ception. beating A wave phenomenon that occurs when two or more periodic waves of different frequencies com- bine to form a periodic amplitude pulsation. In au- dio, beating can quite often be heard and felt as an undulating pulse by those in listening range. See beat frequency, heterodyne. Beaufort notation In meteorology, a code used for indicating the state of the weather. Beaver Falls Glassworks A lesser-known historic utility pole glass insulator fabrication company founded by William Modes in Pennsylvania in 1869. See insulator, utility pole. BEC 1. See Best Effort Capability. 2. Bose-Einstein condensation. BECN See Backward Explicit Congestion Notifica- tion. beehive insulator A type of early glass utility pole insulator, characterized by its beehive shape. See in- sulator, utility pole. BEEP A generic application protocol framework for connection-oriented, asynchronous network interac- tions. In conjunction with other protocols, BEEP can provide reliability, privacy, and authentication op- tions. Through transport mappings, BEEP specifies how messages are carried over the underlying trans- port mechanisms. Profiles may be defined for BEEP. F or example, the RAW profile is a backwardly com- patible, efficient, readily implemented profile for sup- porting legacy Syslog Protocol processing. The COOKED profile is intended for new implementa- tions of Syslog Protocol handler, at the expense of more overhead. See RFC 3081, RFC 3195. beeper Colloquial term for a portable device that alerts the user with an audible tone. Commonly in- corporated into pagers, a beep signifies that there is a message awaiting the user, or some action to be taken as a result of the alert signal. Beginning of Message BOM. In ATM networking, an indicator contained in the fIrst cell ofa segmented packet. The BOM segment is followed by Continua- tion of Message (COM) and End of Message (EOM) segments. A header is associated with the segments and they are passed to the Physical Layer for trans- mission. A two-bit Segment Type (ST) field identi- fies the type. Deilby layerA microcrystalline or amorphous layer that is formed on the surface of metals by polishing. Being There 1. A consumer-priced, Macintosh-based videoconferencing product from Intelligence at Large, which provides video, audio, whiteboard, and file sharing utilities over AppleTalk and TC/IP local area and wide area networks. 2. The title ofa classic Peter Sellers movie. bel symb. - B. A unit of relative power or strength of a signal, which is not commonly used because it is so large. It is used in conjunction with amplitude, usu- ally by its tenth measure, the decibel. Named after 110 Alexander Graham Bell. See decibel. Belden A major commercial manufacturer of com- munications media which has been responsible for influencing cable standards for many telecommuni- cations systems. bell 1. An audio device, often of resonant hollow metal, designed to emit sound when struck, vibrated by a column of air, or vibrated through electrical stimulation. 2. A digitally reproduced simulation of a physical bell, created either by sampling a physical bell and playing back the sound, or by analyzing the type of sound wave patterns produced by aphysical bell and simulating them mathematically. A computer requires built-in electronics or a peripheral sound card in order to send sounds to a speaker, especially ifit's good quality 16-bit stereo sound. Digital music syn- thesizers often have a wide array of bell sound patches from which to choose. 3. A phone bell that is acti- vated by line current from the switching office to in- dicate that there is an incoming call on the line. Alexander Graham Bell- Inventor, Educator Alexander Graham Bell continued to think of him- self as a teacher for the deaf long after he became famous andfinancially independentfrom sales of his technological inventions. He and Helen Keller were friends. Many of the members of hisfamily were known as excellent orators. This portrait was photographed by Moffett Studio when Bell was approximately 69 years of age. [National Archives of Canada, Dept. of ExternalAffairs collection.} Bell, Alexander Graham (1847-1922) A Scottish- born American inventor, who was one of the origi- nal founders of the National Geographic Society. He emigrated to Canada with his family and subse- quently found employment in Boston. He studied aviation, electricity, fresh water distillation, etc., but he is chiefly credited with the invention of the tele- phone. In fact, A. Meucci had tested animal mem- branes as vibrational devices many years earlier and a number of independent inventors in Europe and America were working on ways to transmit tones, and in some cases voice, over telegraph lines. Three sig- nificant contemporaries of Bell who achieved success © 2003 by CRC Press LLC in some of these technologies were Philip Reis, Elisha Gray, and Thomas Edison. In March 1876, two years after working out the origi- nal concept, Bell and his assistant Watson reported having transmitted Bell's spoken voice over electri- cally charged wires, a story that caught the world's imagination and ushered in the telephone age. Bell's patent was filed just hours before a caveat to file was entered at the same office by Elisha Gray, for a simi- lar harmonic telegraph. Bell's talking phone was not demonstrated publicly until some time later. One in- teresting historical note is that Bell's patent did not mention the use ofa liquid medium, yet the rudimen- tary telephone that was later demonstrated did use a liquid medium, a structural detail that was mentioned in the Gray caveat. Model of the First Telephone A model reconstruction of what Bell has described as theftrsttelephone invented by him in 1875, referred to as the "Gallows Telephone" due to its shape. {Li- brary of Congress Detroit Publishing Company Col- lection. Published ca. 1920.J There was significant critical interest in the invention. On 31 Aug. 1876, Anna Joy wrote to Bell, asking him "Was an experiment tried at your office for transmit- ting sound by Electricity? If so when was it tried? Who were the parties engaged? What was the result?" to which Bell gave an uncharacteristically cryptic re- ply: "~Sept.lst, 1876./TheManag.oftheP.&A. T. Co. has forw. to me your note of the 31 st ult. and I beg to state tho expo were made with my app. for the tel. transm. of vol. s. under the direct. of Sir William Thompson at the office of the Pac. & At. Tel. Co. - but at what date I am unable at the pres. mom. to state. /Y rs. truly / A. Graham Bell" In April 1877, Bell acknowledged a request from Boston professionals for a 'practical demonstration of my Electric Telephone' and made arrangements to publicly describe his invention three weeks later. Given all the hedging and the murmur of controversy over the veracity of the original claim, one wonders, in retrospect, if Bell 's famous message to Watson was fabricated or exaggerated because the ambitious Bell was anxious to get the patent before someone else, feeling he was on the verge of success. In 1880, Bell devised a means to transmit phone sig- nals through light, a forerunner to fiber optic com- munications that languished for almost 100 years ~~~~c~rr~i~~:~:~~ technology made the concept. Bell's Historic Telephone Invention Alexander Graham Bell making a historic call by opening the New York to Chicago long-distance line on 18 October 1898. {National Archives of Canada image.J A historic report in the Detroit News on 'Bell sFirst Telephone. '{Library of Congress Detroit Publishing Company Collection, ca. 1920. Photo by Underwood & Underwood, Inc.J In 1882, Bell was granted United States citizenship though he continued to maintain a summer home in Nova Scotia, Canada. Bell achieved enormous financial success and could have ceased working at a young age, but he contin- ued to research aeronautic kites (he succeeded in get- ting a manned, motorized aircraft aloft in 1908), hy- drofoils, and various technologies to aid the deaf, most notably the audiometer. For much of his life, he listed his occupation as teacher of the deaf. 111 © 2003 by CRC Press LLC . portA connecting interface used on Tl sys- tems for interfacing with receive and transmit (e.g., DS 1 inlout) or external timing sources, typically with balanced 10 0- or 120 -ohm termination. Amini-Ban- tam may be used on T1 daughtercards for support- ing an external monitor. In circuit testing, the sleeve on the Bantam connection may be used to ground the circuit. Port Configurations. a comet he observed in 1665, which is richly illustrated in Theatrum Cometum pub- lished in 1666. See Iceland spar, Nicol prism. Barton,Enos Melancthon (1840s-early 1900s) Bar- ton co-founded Western Electric with telegraph/tele- phone pioneer Elisha Gray. He initially fonned a part- nership in 1868 with George Shawk. Shawk rejected an offer to partner with Gray, but Barton was inter- ested in Gray's ideas and Gray & Barton was formed in 1869, evolving into the Western Electric Company in 1872. It is the. radios to act as frequency 105 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary tuners. The windings were of many shapes, cylindri- cal, circular, somewhat spherical. They varied in com- plexity from a dozen turns or so, to many hundreds of turns, in intricate patterns in many layers. By vary- ing the shape, size, and the thickness of the wires, dif- ferent frequencies could be selected. A radio often came with a selection of basket-wound tuners with electrical contacts on the base that could be plugged in as needed. Basov,