Fiber Optics Illustrated Dictionary card An electronic printed circuit board, especially one that is easily dropped into a card slot by adealer or consumer. See printed circuit card, punch card. card hopperIn mechanisms that hold and feed punch cards, the holder in which the cards are stacked next to the feed mechanism for processing. See card stacker. Card Issuer Identifier Code CnD. A calling card identification scheme. There are restrictions on which carriers can issue/use cnD cards. card slotA slot-shaped data connector within an elec- tronic system for the insertion of printed circuit board peripherals. Cards frequently consist of graphics con- trollers, drive controllers, serial and parallel ports, network connectors, and others. PCI is a common format for computer card slots. See edge connector, printed circuit board. cardstacker In mechanisms that hold and feed punch cards, the exit tray in which the cards are stacked af- ter processing. There may be several of these, with a card sorter determining the destination stacker from holes in the cards. See card hopper. Cardano, Girolamo (1501-1576) Also known as Hieronymus Cardanus, Cardano was an Italian math- ematician, physicist, and physician to kings who authored many important historic publications, in- cluding De subtilitate (On subtlety, 1550), describ- ing the accumulated knowledge about amber, with a definite statement that the properties of lodestone and amber differed in significant ways. He further de- scribed these differences. He also proposed the im- portant mathematical notion of imaginary numbers and made a systematic study of probabilities. See amber, lodestone. Girolamo Cardano - Magnetism Pioneer A multitalented pioneer in mathematics and phys- ics, Girolamo Cardano contributedimportant insights to our understanding of magnetism (e.g., properties of lodestone) and theoretical mathematics in the 1500s. CardBus A 32-bit computer data bus designed for use with PCMCIA cards. The CardBus was designed to succeed the PC Card standard. See Personal Com- puter Memory Card Interface Association. 162 cardiode pattern Adiagrammatic representation of the directional response of various transmitting and receiving devices: antennas, speakers, etc. It derives its name from the symmetrical, heart-shaped pattern that is typical. See antenna lobe. Carnegie-Mellon U Diversity This U.S. educational institution is known for many contributions to tele- communications. One of the more familiar is the An- drew File System (AFS) used on computer networks. More recently, developers have created a working, campus-wide wireless data communications system which serves as a model for similar installations else- where and AFS is evolving into a powerful, distrib- uted network protocol with a new name and some in- teresting new capabilities. carrier 1. A wave of constant or known amplitude, frequency, and phase, which can be modulated by changing one of these characteristics. See carrier wave, carrier frequency, Tl. 2. An entity that can carry an electrical charge through a solid. 3. An in- formation-providing radiant energy from space. The four known categories of carriers are electromagnetic radiation, solid bodies, elementary cosmic rays, and gravitational waves. carrier, communications A provider of communi- cations circuits. Common (usually the local phone company) and private carriers are distinguished by degree of regulation and right to access of service by the public. The designation of communications car- rier was intended to encompass companies with their own transmission facilities, as opposed to companies that lease or buy equipment or services for resale, but the general public often uses the phrase more loosely to include all long-distance companies. carrier, GPS AGPS-related radio wave with at least one characteristic (such as frequency, phase, ampli- tude) that can be varied (modulated) from a known reference value. See Global Positioning Service. Carrier Access Code CAC. See Access Code. carrierbandA range of adjacent frequencies that can be modulated to carry information, such as radio broadcast waves (without a carrier wave, multiple frequencies could not be transmitted without signal overlap and disruption). See band, carrier, carrier wave, modulation. carrierbypass A phone service providerdirect-con- nect link to the customer's lines, bypassing the local phone carrier. Some long-distance companies provide services through a carrier bypass in order to provide faster service or less expensive service by avoiding Carrier Common Line Charges. See Access Charge. Carrier Common Line Charge CCLC. A charge paid by phone services providers to a primary car- rier for using their switched network lines. Typically paid by long -distance providers. See Access Charge, carrier bypass. carrier detect CD. Asignal generated by a modem that operates over phone lines to indicate whether the phone carrier is present and the line can be dialed. Many modems have an LED to indicate the presence of the carrier signal. The command to the modem for carrier detect is typically &Cl. © 2003 by CRC Press LLC carrierfrequency 1. The frequency ofacarrier wave intended to be modulated by the wave containing the information. See carrier wave. 2. In the Global Posi- tioning System (GPS), the frequency of the unmodulated fundamental output ofa radio transis- tor. 3. The reciprocal of the period ofa periodic car- rier. See center frequency. Carrier Identification Code CIC. A short code to identify uniquely a secondary phone service carrier for routing and billing. It was formerly three charac- ters, but the Industry Carrier Compatibility Forum in 1988 and Bellcore in 1989 informed the Chiefof the Common Carrier Bureau that four characters were needed to meet increasing demand. The numbers are issued by the North American Numbering Plan Ad- ministration (NANPA) to authorized entities. The ex- pansion from three to four digits was termed the Plan of Record (POR). The implementation of this plan would not be trivial as it involved administrative changes and expenditures on the part of Local Ex- change Carriers (LECs) and change-over expenses to anyone publishing materials with CICs (directories, letterheads, marketing materials, etc.). It also required procedures and priorities for conserving and reusing scarce CIC resources. By the mid-1990s, Bellcore began assigning·four- digit Feature Group D CICs. In 1998, this was fur- ther changed to aprefix (e.g., "1 0+1 Oxxx") followed by the number, thus bypassing the subscription car- rier (which would use the prefix code"1"). See Ac- cess Code, North American Numbering Plan. carrierselect keys Buttons included on a phone (usu- ally a payphone) to provide the caller with a quick way to select a long-distance provider, thus not hav- ing to key in extra digits for access codes. carrier selection Selection by a phone customer of a long-distance provider, usually done at the time of ordering the service, but it can be changed at any time. If you select aprimary long-distance carrier, you will be able to access the service by dialing "1" plus the number. For alternate long-distance companies, you have to enter additional digits or access codes to com- plete a call. There are many long-distance companies, each offering better features and lower prices than the next. Evaluate these carefully before switching ser- vices, as there may be inconveniences, hidden charges, or limitations that are not apparent from the advertising literature and that may result in service that is limited and not necessarily cheaper in the long run. See Access Code, carrier bypass. carrier sense The capability ofa station to continu- ously monitor other stations to see if they are trans- mitting. See Carrier Sense Multiple Access. CarrierSense MultipleAccess CSMA. A listen-and- send protocol used on local area networks (LANs). A system readying to transmit first probes the net- work to see if the line is clear; in other words, it en- sures that another workstation is not transmitting. If the coast is clear, it sends the transmission. This pro- tocol does not guarantee that collisions don't occur; it simply reduces the likelihood of an immediate col- lision. Various versions of CSMA exist to enhance its efficiency and provide greater collision detection and avoidance. Carrier Sense Multiple Access with Collision Avoidance CSMA/CA. A version of Carrier Sense Multiple Access that is used in Ethernet systems in association with Media Access Control (MAC) pro- tocols to integrate collision detection with time-di- vision multiplexing (TDM). It aids in improving ef- ficiency in CSMA systems. See Carrier Sense Mul- tiple Access. Carrier Sense MultipleAccess with Collision De- tection CSMA/CD. Aversion ofCSMA with added traffic flow control capabilities to detect collisions, in order to increase the efficiency of flow ofinfor- mation on a local area network (LAN). CSMA/CD is not ideal for all implementations. In satellite com- munications, for example, the transmitting Earth sta- tions cannot engage carrier sensing on the uplink due to its point-to-point nature. See Carrier Sense Mul- tiple Access. carrier shifting A technique of moving an entire modulated wave sequence in a positive or negative direction with respect to its midpoint, without chang- ing the overall shape of the envelope. Carrier shift- ing is often used to manipulate mathematically a wave or to recreate a wave based upon only partial infor- mation (e.g., sideband). See phase shift keying. carrier shifting fault An undesirable condition in transmitting a modulated carrier wave, in which the envelope, the range ofamplitude-modulated signals above and below the midpoint of the waves, is un- balanced. carriersignalA continuous radiant wave that can be modulated to add information to the wave. Carrier signals are modulated in a variety of ways; the two most familiar are amplitude modulation (AM) and frequency modulation (FM). One of the first research- ers to search for a way to add information to acarrier wave was R. Fessenden, an American inventor who devised the hot-wire barretter and a high-frequency wave generator in 1901. Later, 1. Carson studied the mathematical properties ofcarrier signals and pro- posed ways ofcarrying information by manipulating and recreating the signal at the receiving end, thus saving transmissions bandwidth. See Carson, John Renshaw; Fessenden, Reginald Aubrey; modulation; single sideband. carrier synchronization In radio broadcasting, a carrier wave is used to carry a signal through a pro- cess called modulation, wherein information is added to the carrier wave. Various means of sending the modulated wave have been developed, some of which send only the sidebands, some of which send one side of the signal and recreate the other, etc. Consequently, at the receiving end, the receiver has to be designed so it can properly process the type of wave that is being received. In some cases, this situation involves the creation ofa reference carrier that is synchronized with the received signal. See Carson, John R.; single sideband. carrier to interference ratio CIR. A quantitative description of the effective transmission in relation 163 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary to the (undesired) interference affecting that transmis- sion. This ratio is of special interest to wireless com- munications engineers in designing transmissions components such as antennas and transceiving equip- ment. It is ofincreasing importance as vendors seek to increase the capacity ofexisting systems without degrading the signal to the point that the customers are unhappy with the service. carrier wave A single-frequency wave that carries the transmission by being modulated by another wave containing the information. Acarrier wave provides multiple channels and a means to reduce signal over- lap through multiplexed broadcast waves. See carrier. carrierless amplitude and phase modulationCAP modulation. A coding technique, based upon quadra- ture amplitude modulation, used in Digital Subscriber Line (DSL) transmissions. See discrete multitone, modulation, pulse amplitude modulation. CARS See Cable Television Relay Service Station. Carson, John Renshaw A mathematician and re- searcher at Bell Laboratories who contributed math- ematics fundamentals related to modulation of com- munications waves that provided a way to recover the whole band from sideband transmissions. In 1915, he demonstrated that separate channels could be carried on each of the sidebands ofa modulated carrier wave. In 1922, he provided a mathematical description of frequency modulation (FM) (and is somewhat infa- mous for having disagreed with E. Armstrong about the feasibility ofFM transmissions). He was awarded the Franklin Institute Cresson Medal in 1939. See Armstrong, Edwin Howard; Carson's Rule. Carson's Rule A method for calculating the mini- mum bandwidth of a frequency-modulated signal needed to transmit the desired communication. A larger number ofsubcarriers will necessitate awider Carson's bandwidth. Named after John R. Carson. Carterfone A commercial device developed in the 1960s for acoustically connecting two-way mobile radio communications to a telephone network system. Developed by Thomas Carter, who battled for the right to connect into the public phone network, the system became known through an important judg- ment by the Federal Communications Commission (FCC). Carter didn't sell many of the devices, but AT &T saw the precedence as threatening enough, in terms of its implications for other vendors, to obstruct its use. See Carterfone Decision. CarterfoneDecisionA 1968 landmark judgment by the Federal Communications Commission (FCC) in which existing interstate telephone tariffs that pro- hibited subscribers from attaching their own phone equipment to existing phone lines was struck down. Carter Electronics had sought since 1966 to acousti- cally interconnect its private mobile radio systems to the national exchange network through a voice-acti- vated system that started the radio transmitter. In pur- suing its own right of access, Carter Electronics paved the way for other companies as well and, in a sense, foreshadowing the divestiture of AT&T. As a result of the Carterphone Decision, manufac- turers other than Western Electric, which had exclu- 164 sive arrangements with AT&T, no longer were pre- vented from using the resources, and the interconnect industry was born. See Carterfone, Hush-a-Phone de- cision. cartridge A common type of magnetic removable data storage that works somewhat like a floppy dis- kette but is physically larger in size and significantly higher in storage capacity. Cartridges commonly hold between 200 Mbytes and 1 Gbyte of data uncom- pressed. With the introduction of super-capacity disks, 3.5" floppies that can store more than 1 00 Mbytes of data, the discrepancy between low-capac- ity cartridges and high-capacity floppies is less than low-capacity floppy drives. Rewritable CDs are now beginning to compete with cartridges as backup stor- age devices due to the less volatile nature of the data. Carty,John J. (1861-1932) Chief engineer of AT &T in the early 1900s after serving as the head of West- ern Electric's cable department. Carty developed the frrst two-wire telephone circuit and the phantom cir- cuit, through which three conversations could be transmitted at one time over two pairs of wires. West- ern Electric purchased the rights to Lee de Forest's Audion, a three-electrode tube, in time for Carty to fulfill a promise he made in 1909 to provide a trans- continental telephone service to the U.S. west coast by 1914. See AT&T, phantom phone. Carty, John J., Award for the Advancement of ScienceAtriennial award for noteworthy and distin- guished accomplishment in science. This award has been directed towards a different field every three years since 1932. It was established by AT&T. CAS 1. CentralizedAttendant Service. Acentralized group of operators servicing systems which may have a number ofbranches within a region. 2. See chan- nel associated signaling. 3. See Communications Applications Specification. cascade To arrange or pattern into aseries or succes- sion of steps or stages, each dependent upon, or de- rived from the preceding, often in a falling or down- ward hierarchy. Computer menus, file systems, ap- plications windows, and other graphical and logical structures are often developed with a cascade struc- ture. Text editing applications sometimes have tele- scoping and cascading outline capabilities. Cascad- ing principles and properties are now being studied with relation to quantum effects and harnessed for commercial applications. See quantum cascade laser. CASE computer-aided software engineering, com- puter-assisted software engineering. case sensitive 1. Computer software data or processes in which the case (lower or upper) is considered sig- nificant to the meaning of the text. For example, file names on Unix systems are case sensitive; that is, "MyFile.txt" is different from "myfile.txt". Case sen- sitive file names result in a greater range ofdescrip- tive naming possibilities. MS-DOS systems are case insensitive. AmigaOS is partly case-sensitive, forgiv- ing about case when traversing directories in the shell, but allowing file names that can be distinguished from one another by case. 2. In word processing, search and replace routines can usually be configured to be © 2003 by CRC Press LLC case sensitive or case insensitive, depending upon your needs. 3. On the Web, URLs are case sensitive, but for the convenience of users many browsers will resolve the cases in a forgiving manner, to load a Web page even if the case is misspecified. This feature is not characteristic of all browsers, so it's usually bet- ter to type in the case correctly. case sensitive password For access to secure com- puter systems, most password fields require an exact match, hence are case sensitive, in order to provide a greater variety of possible passwords and thus in- creased security. Case sensitivity also increases the total number of possible passwords, which is impor- tant if it is a multiuser environment with a limit on the number of characters in the password (e.g., eight characters ). Cassegrain antenna, Cassegrainian antenna A parabolic antenna arrangement in which the feed is located near the vertex ofa concave surface of the main reflector, and a secondary reflector is located near the focal point and aligned to be within the fo- cus of the main reflector. A beam is thus redirected from the feed unit through the secondary reflector to the main reflector to radiate a beam that is parallel to the axis of the main reflector. A Cassegrain feed is one type of arrangement; hom feed is another. Cas- segrain antennas require more careful alignment and more parts than a hom feed antenna and thus tend to be used in higher end, more expensive applications. Due to the redirection of the reflection, they stay cooler than hom feed arrangements and are thus suit- able for hotter climates. See antenna; hom feed; para- bolic antenna; Ramsden, Jesse. Cassegrain,Guillaume (dates unknown) Apparently a French founder and sculptor who developed a cen- ter mirror telescope even before Newton constructed a reflecting telescope. In 1672, Cassegrain proposed using a main mirror with a hole in the center, with a smaller hyperboloid mirror to reflect back the image through the hole to an eyepiece. This arrangement results in a compact design and minimal spherical and chromatic aberrations in the image. It is the same general configuration of some of the advanced tele- scopes of today. See Cassegrain antenna. cassette tape A portable recording and playing me- dium consisting of a long narrow magnetic tape wound onto reels protected by a roughly rectangular plastic case. Cassette tapes come in a variety of tape widths and are used for both sound and video. Some audio tapes are wound onto the reel in a loop to enable continuous playing, but most are manually turned over or mechanically rewound. Cassettes are commonly used for consumer audio and backup and archiving of computer data. Very small cassette tapes are used in answering machines and small tape re- corders designed for maximum portability (and, in some cases, minimum visibility). Cassette tapes for consumer audio almost completely replaced reel-to- reel tape, then began to be supplanted by audio CDs and other digital audio technologies. See CD, DAT, leader, reel-to-reel. Cassini A spacecraft designed to travel through the solar system and send back information to be evalu- ated by scientists to teach us more about our plan- etary environment and the universe. The Cassini spacecraft has many tasks to perform on its way to the planet Saturn. Flyby targets include Venus, Earth, ~~;~~~~;~~~~~:;~~~~t~~~;~i~:~b~f~<'11 maneuvers and flybys needed to take it on its seven year journey to Saturn. The telecommunications and guidance systems associated with the Cassini mission are some of the most sophisticated to date and will teach us much about how far and how well we can transmit information to and from the comers of the Galaxy. castellationAn indented pattern or surface ofa regu- lar, repeated nature. For example, the battlements on castles are castellated. Castellated protruberances, or thin pads of conductive materials, are often incorpo- rated into the edges of electronic circuit boards to pro- vide contact points for electrical connections. Grat- ings are often castellated components. cat, Cat abbrev. category. In cabling, Category, or Cat followed by a number denotes industry-specific cabling standards. See category ofperfonnance. CAT 1. Call Accounting Terminal. An AT&T term for a microprocessor-equipped device that records call activity in order to provide automated account- ing information. 2. See computer-aided teaching, computer assisted instruction. 3. See Council for Access Technologies. catadioptric devices Devices that utilize both opti- cal reflection and refraction to control the travel of light through the device, often to produce an image for viewing or transission. Depending upon the in- strument, the catadioptric configuration may be in- tended to shorten the length of the barrel ofa view- ing device or process the light signal as it is being reflected and refracted. Catadioptric principles are used in a variety of astronomical telescopes, robot- ics imaging technologies, and some digital video cam applications. Catarra See PDA marcrobrowser, SoftSource Corp. category, wiring See category of performance. category of performance Cabling and component standards that have been defined to promote and fa- cilitate intercompatibility of products from different vendors. These standards are widely used in the phone and computer network industries, especially Cat 5. The categories of performance focus on the through- put of the transmissions rather than the specific ma- terials used to construct individual cables. They are self certifying in the sense that the vendor is respon- sible for testing and maintaining quality and manu- facturing standards to provide the performance cat- egories detailed in the Categories chart. catbode (symb. - K) 1. The negative terminal of an electrolytic cell. 2. The positive terminal of current- supplying primary cell. 3. In a moving electron sys- tem such as an electron tube, the electron-emitting portion, directed toward an anode, often a thin metal 165 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary plate, usually passing through acontrolling grid. The electron beam-emitting end of a cathode-ray tube (CRT). See cathode-ray tube, phototube, photomul- tiplier tube. Cathode-Ray Tube - Basic Parts Cathode in Electron Tube The cathode is one of the three essential elements of an electron tube, emitting the electrons that are at- tracted to the anode. In this tube, the filament acts as the cathode. The movement of the electron beam across the dis- play surface excites the phosphors so that they selec- tively light up (fluoresce) and remain visible for a few moments. The sweep of the beam is very fast so that perceptually humans will 'see' the entire frame as one image rather than as a series ofconstantly refreshed lines. Sometimes agrating called a shadow mask is inserted between the beam and the coating to further control and focus the beam to provide a crisper display. Cathode-ray tubes can be short persistence or long persistence. Long persistence means the phosphors remain lit for a longer period of time, and the screen may not have to be refreshed as often to keep an im- age visible. The refresh rate on most current monitors is 60 frames Cathode-ray tubes are essential components in many types of electronics devices. They are widely used as display devices for televisions, radar scopes, oscillo- scopes, computer monitors, etc. This diagram of a his- toric electromagnetic-deflection cathode-ray tube pro- vides an example of the basic, essential components. phosphor coating on inside of tube deflecting coils anodes cathode rayAn ionized region, composed ofa stream ofelectrons influenced by an electric field, emanat- ing from a cathode. See cathode-ray tube. cathode-ray tube CRT. Adisplay device consisting ofaclosed tube of glass with the air removed; it con- tains an electron-emitting gun at one end and a coated surface at the other. The cathode-ray electron beam emanates from the cathode and passes through a mag- netic field that controls the beam. By sweeping across the coated inside surface of the glass, a frame is fonned on a raster display and a vector is formed on a vector display, either of which can be seen through the glass from the outside. cathode (filament) Categories ofPerformance Category Transmission Rate Notes Cat 1 Not used Cat 2 Not used Cat 3 Up to 16 megahertz 24-gauge wire. Typically used in voice communications and lower end data communications, such as Token-Ring and 10-Mbps Ethernet networks. Cat 4 Up to 20 megahertz Digital voice communications and data networks, e.g., Token- Ring. Cat 5 Up to 100 megahertz 24-gauge wire with more stringent fabrication requirements than Cat 3 (e.g., better shielding). Typically used in higher end data communications and high-grade or digital voice applications, particularly high-bandwidth ones such as videoconferencing. Examples include FDDI, lOOBase-T, lOO-Mbps Token-Ring or Ethernet. See twisted pair for a diagram. 166 © 2003 by CRC Press LLC per second, a rate that is fast enough to appear stable and not flickering to the human eye. Color CRTs typi- cally have three beams, red, green, and blue (RGB). The cathode-ray tube is fragile and large (regretta- bly) and is typically encased in aprotective console. It is not advisable for laypersons to open the back of a CRT device, as there is a danger ofelectric shock from the stored charge. CRTs were being used as computer display devices by the early 1950s but did not become regularly associated with microcomput- ers until 1976. CRTs are commonly used for moni- tors (computers, video editing, scopes) and television screens. See Crookes tube; flat panel CRT; frame; Geissler tube; interlace; screen saver; shadow mask; Zworykin, Vladimir Kosma. cathodic protection In many wiring installations, bare wire is used, so corrosion is a significant con- cern. One of the ways to prevent corrosion and buildup is by running a negative charge through the wire to repel negative ion materials such as chlorine. CATNIP See Common Architecture for Next Gen- eration Internet Protocol. CATS See Consortium for Audiographics Telecon- ferencing Standards. CATV I. Cable Television. A system that delivers fre- quency-segmented television programming channels to subscribers through physical cables, usually 75-ohm coaxial cables. The full bandwidth of cable is not typically used, partly due to the extent of the subscriber's service and partly due to the insertion of non-pro gram-carrying guard bands that act as sepa- rators to keep individual channel transmissions from interfering with one another. 2. Community Antenna Television. A large antenna, shared by a community, to intercept broadcast stations that are not accessible via small, individual antennas. Sometimes commer- cial communities (motels, resorts, condominiums) will make arrangements to install apowerful antenna and rebroadcast or channel the signals to individual units. In many cases, this will require a special license as there are laws protecting broadcasters from hav- ing their programs rebroadcast. catwhiskerA fine metal thread resembling the arched shape of a cat's whisker, used in early radio wave detecting crystal sets. The catwhisker contacted the crystal on one end and was secured to a metal con- ductive support on the other end. Some enclosed sets used a catwhisker that was fixed in place at the fac- tory. Prior to the commercialization of crystal sets, it was known as a feeler. See crystal detector. CAU See controlled access unit. CAY See constant angular velocity. cavityA depression, hole, indentation, or pit, which may be of any size. In various media, cavities ofpre- cise characteristics are created in the surface so they can later be used to deflect radiant waves or carefully focused laser light beams. The deflections pass into some kind of pickup mechanism (read mechanism) so the encoded information can be recreated and pre- sented. Thus, cavities are at the heart of many opti- cal recording technologies, CDs, for example. cavity magnetronAn early British innovation in radar systems, developed in 1940, that enabled the use of extremely short waves (microwaves). Thus, it was possible to design more compact antennas and im- prove the quality of the information and images that could be resolved through radar systems. Smaller beam widths facilitated greater accuracy. In tum, the smaller, more accurate radar technologies greatly in- creased the number and types of applications that were practical, making it possible to mount radars on boats and planes. See magnetron. CD radio See citizen's band radio. CDC See Canadian Broadcasting Corporation. CDDS 1. Common Basic Data Set. 2. See Con- nectionless Broadband Data Service. CDEMA Computer and Business Equipment Manu- facturers Association. See Information Technology Industry Council. CDRAnATM traffic flow control concept. See con- stant bit rate. CDS See Columbia Broadcasting System. CDSC See Canadian Broadcast Standards Council. CDT 1. See Canadian Business TelecommUnications Alliance. 2. Computer-Based Training. See com- puter-assisted instruction. CDTA See Canadian Business Telecommunications Alliance. CDX Computerized Branch Exchange. A commer- cial private telecommunications system trademarked by the ROLM Corporation as their version ofa pri- vate branch telephone exchange (PBX). CDYD Call Before You Dig. The warning on signs by fiber optic cables to prevent contractors and other diggers from damaging underground installations. CCD See Common Carrier Bureau. CCC 1. clear channel capability. In communications, that portion ofa data transmissions capacity that is available to users, the informational portion, above and beyond the various control and signaling trans- missions associated with the functioning of the tech- nology. 2. Communications Competition Coalition. A Canadian support and lobbying organization estab- lished to encourage Canadian telecommunications competition. 3. Center for Corporate Communica- tions. http://www.communicationsmgt.org/4.Com- puter Communications Club. http://www.ccc.or.at/ CCD 1. See charge coupled device. CCI See co-channel interference. CCIA See Computer and Communications Industry Association. CCIR 1. See Centre for Communication Interface Research. 2. See Comite ConsultatifIntemational des Radiocommunications. CCIR video standard Similar to the EIA RS-170a standard for color video, CCIR is a dominant video format used in Europe just as NTSC is standardized in North America and Japan. CCIR supports a verti- cal resolution of625 scanlines, 575 of which are typi- cally displayed. It is an interlaced format with two scans of the screen combining to create a conceptual frame. The number oflines per field (two of which make up the frame) is 282.5 compared to 242.5 for RS-170a. The effective resolution when conversion 167 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary with raster-based displays is desired is 768 (compared to 640 for RS-170a). CCIR video is traditionally transmitted over 75-ohm well-shieldedcoaxial cables. CCIRN Coordinating Committee for Intercontinen- tal Research Networks. Established by the U.S. Fed- eral Networking Council (FNC) and the European Reseaux Associees pour la Recherche Europeenne (RARE). CCIRN promotes international cooperation and sponsors a number of working groups that meet in different parts of the world. CCIS See Common Channel Interoffice Signaling. CCITT Comite Consultatif Internationale de Telegraphique etTelephonique. International Telegraph and Telephone Consultative Committee. An influen- tial United Nations-sponsored international telecom- munications standards committee based in Geneva, Switzerland. It changed its name to lTU in 1990. See International Telecommunication Union. CCITT Study Groups These subgroups, operating under the CCITT (now the lTD) study and make rec- ommendations for specialized areas of telecommu- nications. See International Telecommunication Union. CCNR(telephone) call completion on no reply (e.g., as in ISDN Q.733 call completion services). CCP See Compression Control Protocol. CCR See current cell rate. CCS See Common Channel Signaling. CCS/SS7 Common Channel SignaVSignaling Sys- tem 7. See Signaling System 7. CCSN Common Channel Signaling Network. See Common Channel Signaling. CCT 1. Calling Card Table. See unmatched call. 2. See Consultative Committee Telecommunications. Common CD Formats Format Description CD-Audio Compact disc audio. A digital sound representation standard that is incorporated into CD- ROMs. Conversion from digital to analog for listening occurs in the computing hardware. Also known as Redbook Audio. CD-I Compact disc interactive. An interactive multimedia standard developed by Philips and Sony. CD-I players are designed to accept and playa variety of CD-encoded data and can typically be interconnected with a computer or TV playback system. CD-Plus Compact disc plus. A standard developed by Philips and Sony that enables audio CD players to play multimedia (graphics and sound) discs by skipping over the nonaudio segment that is stored on the frrst track. CD-R, CD-ROM R Compact disc recordable. A format for read/write CD-ROM systems. See compact disc for a fuller description. CD-ROM Compact disc read only memory. A standardized, widely used format for storing digital information on small flat optical platters that are read with laser technology and played on CD players. See compact disc for a fuller description. CD-ROM A computer peripheral that reads, and sometimes writes, digital information to a compact disc. Most consumer CD-ROM drives are read only, although read/write drives are now under $300 and may soon be a consumer item. A CD-ROM drive can be used to run applications, read text files, images (PhotoCD), and audio. Many CD-ROM drives come with software to play audio CDs through a speaker. CD-ROM X A compact disc read only memory extended architecture. A fonnat developed by Microsoft that enables the interleaving of audio and video, rather than recording them on separate tracks. It requires a player that can understand the format. If played on a regular player, the audio will not be detected and played. CD-RW CD recordable/rewritable technologies that became prevalent in the late 1990s and which were almost immediately challenged by emerging DVD technologies. CD-UDF A standardized fonnat for CD-recordable (CD-R) media that enables a variable packet- writing scheme to be used as an incremental approach to the recording of compact discs (CDs). It provides a means for easily recording files on a CD in much the same manner as on a floppy disk. CD-V Compact disc video. A standard for storing video images on compact discs that hasn't really caught on. It is being superseded by CD-XA which enables the interleaving of video and sound. CD-WO Compact disc write once. A fonnat designed for mastering a CD. The CD is then used in- house or in limited quantities, or is sent to a duplication factory for mass production. Drives that are able to write a master CD were once out of the price range of small companies and consumers, but they have dropped to below $300 and can now be used by software developers, composers, and small record companies to produce masters or small production runs of specialized recordings. 168 © 2003 by CRC Press LLC CCTA See Central Computer and Telecommunica- tions Agency. CCTV Closed Circuit TV. See closed circuit broadcast. CCU 1. camera control unit. 2. communications control unit. CD 1. See carrier detect. 2. See compact disc. See Common CD Formats chart.3. count down. A con- cept in broadcasting related to the signaling of the be- ginning of taping, editing, or live broadcasting. CDA See Communications Decency Act. CDCS Continuous Dynamic Channel Selection. CDDI See Copper Distributed Data Interface. CDE See Common Desktop Environment. CDF See cutoffdecrease factor. CDLC See Cellular Data Link Control. CDMA See code division multiple access. CDMP Cellular Digital Messaging Protocol. CDO See community dial office. CDP 1. Cisco Discovery Protocol. 2. Customized Dial Plan. CDPD See Cellular Digital Packet Data. CDPD Forum, Inc. A not-for-profit organization established in 1994 to promote the development and acceptance ofCellular Digital Packet Data (CDPD). It supports vendors who develop and distribute CDPD products and services. http://www.cdpd.org/ CDR See Call Detail Record. CDRH classifications A series ofclassifications to alert users of the dangers of incorrect use of laser- based components that emit external beams (more powerful lasers may be inside the assembly but must not emit to the exterior of the device). The laser safety classification categories are somewhat generalized since the wavelength of the light is an additional fac- tor controlling the influence of the beam and is not specified for all categories. CDT credit allocation. In packet-switched networks, such as OSI, CDT applies to transmission flow control. CDTAC See Consumer/Disabilities Telecommuni- cations Advisory Committee. CDV 1. cell delay variation. 2. See Compressed Digital Video. CDVT See cell delay variation tolerance. CE Connection endpoint. 1. In ATM networking, a terminator at one end ofa layer connection within a SAP. 2. circuit emulation. CE Mark A sign that an object has been certified through the overseeing European regulatory body, the European Telecom Directive, and does not require further testing or approval within the individual par- ticipating countries. The mark provides identification ofproducts that conform to certain specified safety, electromagnetic, and interoperability requirements. CE certification is required for all telecommunica- tions terminal equipment (TTE) sold in the European Union. See Underwriters Laboratory, Inc. CEBus ConsumerElectronics Bus. A home automa- tion standard managed by the CEBus Industry Coun- cil and accepted by the Electronics Industry Associa- tion (EIA). CEBus specifies a common format for connectionless peer-to-peer communications over standard electrical wiring. The CEBus HomePnP standard is anonproprietary protocol based upon the lEA 600 open standard. In terms of functionality, it is similar in concept to the X-I0 protocol in that it operates over 120-volt, 60-cycle home wiring. CEBus is a two-channel specification, with one chan- nel assigned to realtime control functions, the other to informational data. It uses a CSMA/CD protocol that includes various error detection and retry func- tions, end-to-end acknowledgment, and authentica- tion. The Powerline Carrier uses spread spectrum technology to bypass electrical impediments in home wiring, spreading the signal over arange of frequen- cies rather than using a single frequency. See spread spectrum, X-IO. CEBus Industry Council CIC. A users group sup- porting the development and use of interoperable CEBus-based home network automation technolo- gies. http://www.cebus.org/ CEDAR The Center of Excellence for Document Analysis and Recognition. An organization at the CDRH Laser Safety Classification Categories Class Designation Notes Class I EXEMPT Visible, low-powered lasers considered safe for viewing. Class II CAUTION Visible lasers in the 600 to 700 nm range at 1 mW or less. Do not stare directly at the beam or a reflection of the beam. Class lila DANGER Visible lasers in the 600 to 700 nm range at 5 mW or less. Severe eye damage; avoid eye exposure to the beam or areflection of the beam. Class IIIb DANGER Visible lasers in the 600 to 700 nm range at 5 mW or greater and invis- ible lasers in the 700 to 900 nm range. Severe eye damage; avoid any exposure to the beam or reflection of the beam. Doesn't present fire haz- ard. Class IV DANGER High power lasers exceeding characteristics of Class III lasers. They present avariety of dangers from eye and object damage to diffusion haz- ards, burns, and general fire hazards. 169 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary State University of New York at Buffalo that provides a number ofinteresting services including informa- tional CD-ROMs. CEI In ATM networking, a connection endpoint identifier. Celestri A downsized version of the original M-star project, Celestri is a low Earth orbit (LEO), geosta- tionary hybrid satellite system from Motorola. In May 1998, the Celestri expertise and technology was rolled into the Teledesic project, when Motorola Inc. bought in as a major partner. See Teledesic. cell, ATM In asynchronous transfer mode network- ing, a unit oftransmission consisting ofa fixed-size frame comprising a header and a payload. See asyn- chronous transfer method, cell rate. cell, battery Minimally, a receptacle containing an electrolyte and two electrodes arranged so the elec- tricity can be generated from the cell by chemical actions. Development of modem cells stems from the experiments of C.A. Volta. Two or more cells can be combined to form abattery. See battery, storage cell. cell, mobile phone In mobile communications, the basic geographic unit ofa distributed broadcast sys- tem, within which a low-power transmitting station is located. Roughly hexagonal in shape, depending upon terrain. Its size varies with available channels, generally increasing as the radius of each cell de- creases. Cells are further grouped into clusters. See cluster, cellular phone, mobile phone. cell delay variation CDY.In AIM networking, a traf- fic flow buffering and scheduling concept. CDV pa- rameters are associated with constant bit rate (CBR) and variable bit rate (VBR) services and relate qual- ity of service (QoS) information by indicating the probability that a cell may arrive late. See cell rate. cell delay variation tolerance CDVT. In ATM net- works, a traffic flow control mechanism that allows cells to be queued during multiplexing to allow oth- ers that are being moved onto the same communica- tions path to be inserted. Cells may also be queued to allow time for the system to insert control cells of one sort or another. See cell rate. cell error ratio In ATM networks, the ratio of cells in a transmission that are errored to the total cells in the transmission, over aspecified time interval, pref- erably as measured on an in-service circuit. See cell loss ratio, cell rate. cell interarrival variation CIY. In ATM networks, a description of changes in arrival times of cells near- ing the receiver. If the cells are carrying information in which the arrival of the cells at the same time is important to the synchronization of the final output, as in constant bit rate (CBR) traffic, then latency and other delays that cause interarrival variation can in- terfere with the output. For example, in videoconfer- encing, synchronization of images and sound might be affected by cell delays. See cell rate, cell delay variation tolerance, jitter. cell loss priority field CLP. In ATM networks, a bit field contained in the header cell that indicates the cell discard eligibility of the cell. In congested situa- tions, this cell may be expendable. 170 cell loss ratio CLR. In ATM networks, cell traffic is handled in many ways in order to maximize through- put, to synchronize arrival times where appropriate, and to minimize delays, latency,jitter, or loss. The cell loss ratio is a negotiated quality of service (QoS) param- eter that depends upon the network traffic flow con- trol setups. It is computed as a ratio of lost cells to the number of total cells transmitted, expressed as an order ofmagnitude. See cell error ratio, cell loss pri- ority field, cell rate, leaky bucket. cell misinsertion rate CMR. In AIM networking, a traffic flow evaluation parameter giving the ratio of cells that are received at the endpoint, that were not originally transmitted by the source, compared to the total number ofcells correctly transmitted. cell phone See cellular phone. cell rate In ATM networks, a concept that expresses the flow of basic units of transport used to convey data, signals, and priorities. See the Cell Rate Con- cepts chart for further detail. See leaky bucket, cell rate margin. cell rate margin CRM. In ATM networks, an expres- sion of the difference between the effective band- width allocation for the transmission and the sustain- able cell rate allocation in cells per second. cell relay A type of fast packet switching network architecture using small fixed length packets that can be used for avariety of data types. The cell format is typically 53 octets comprised of 5 bytes of address information and 48 bytes ofinformational data. Cell relays can also provide quality ofservice (QoS) guar- antees to a variety of services. See Frame Relay. cell relay function In ATM networking, a basic ser- vice provided to ATM endstations. See cell relay. cell relay service CRS. An ATM carrier service. cell reversal In a battery, a reversal of the polarity of the terminal cells resulting from discharge. cell site In cellular wireless communications systems, an individual transceiving unit. Multiple cell sites pro- vide roaming capabilities. The cell site serves the lo- cal cell and slightly overlaps with adjoining cells to minimize dead spaces between transmissions when a subscriber passes from one cell region to another. cell site controller Cellular radio operates with nu- merous cells, each associated with a transceiver. The cell site controller manages the various radio chan- nels within that cell, allocating them when a user moves into range of the cell, and deallocating and re- using available frequencies as the user moves out of range again, or terminates the connection. cell splitting A means ofincreasing the call capacity ofa cellular system by splitting cells into smaller units. cell switch router CSR. A network routing device that incorporates ATM cell switching in addition to conventionalLP datagram forwarding, in order to pro- vide improved service over traditional hop-by-hop datagram forwarding, especially with transmissions that pass through subnetwork boundaries. See RFC 2098. cell switching In cellular mobile phone systems, the overall process ofhandling calls, monitoring signals as users move in and out of range of the transceivers © 2003 by CRC Press LLC in the various cells, and allocating and deallocating frequencies as needed to provide seamless service through a series of cells. Cells are designed to over- lap somewhat so that there is no gap when switching from one to another and to compensate for the fact that the signal is weakest on the periphery of the trans- mitting area. The sophisticated moment-by-moment monitoring and orchestrating of this process is handled by monitoring systems and cell-switching software. cell transfer In cellular mobile phone systems, the logistics of keeping an ongoing connection at accept- able volume and quality levels when switching the user from the transceiver in one cell to the transceiver of the cell that is being entered. This transfer involves allocating a frequency channel in the entered cell and deallocating and reassigning, if needed, the frequency channel of the exited cell. cell transfer delay CTD. In ATM networking, the time elapsed between a cell exit event at the first point of measurement and the corresponding cell entry event at the second point of measurement for a par- ticular connection. The cell transfer delay between the two points of measurement is the sum of the total inter-ATM node transmission delay and the total ATM node processing delay. See cell rate. CelloAgraphical Web browser created at the Cornell Legal Information Institute. cellphone See cellular phone. cells in flight CIF. In ATM networking, a descrip- tive phrase for a traffic service parameter, the avail- able bit rate (ABR). CIF is a cell number limit nego- tiated between the receiving network and the source of the cells during the idle startup period, prior to the fIrst RM-cell returns. See cell rate, Cells in Frames. Cells in Frames CIF. The name given to a number of mechanisms for carrying ATM network traffic across a media segment and network interface card. CIF was developed by the Cells in Frames Alliance, a diverse group ofprofessionals and commercial ven- dors. This group released the fIrst CIF sp~cification in 1996 for carrying ATM over Ethernet, Token-Ring, Cell Rate Concepts in ATM Networks Abbreviation/Function Descriptor Notes ACR allowed cell rate A traffic management parameter dynamically managed by congestion control mechanisms. ACR varies between the minimum cell rate (MCR) and the peak cell rate (PCR). CCR current cell rate Aids in the calculation of ER and may not be changed by the network elements (NEs). CCR is set by the source to the available cell rate (ACR) when generating a forward RM-cell. COP cutoff decrease factor Controls the decrease in the allowed cell rate (ACR) associated with the cell rate margin (CRM). CN cell interarrival variation Changes in arrival times of cells nearing the receiver. If the cells are carrying information that must be synchronized, as in constant bit rate (CBR) traffic, then latency and other delays that cause interarrival variation can interfere with the output. GCRA generic cell rate algorithm A conformance enforcing algorithm that evaluates arriving cells. See leaky bucket. ICR initial cell rate A traffic flow available bit rate (ABR) service parameter. The ICR is the rate at which the source should be sending the data. MCR minimum cell rate Available bit rate (ABR) service traffic descriptor. The MCR is the transmission rate in cells per second at which the source may always send. PCR peak cell rate The PCR is the transmission rate in cells per second that may never be exceeded, which characterizes the constant bit rate (CBR). RDF rate decrease factor An available bit rate (ABR) flow control service parameter that controls the decrease in the transmission rate of cells when it is needed. See cell rate. SCR sustainable cell rate The upper measure ofa computed average rate of cell transmission over time. UBR unspecified bit rate An unguaranteed service type in which the network makes a best efforts attempt to meet bandwidth requirements. VBR variable bit rate The type ofirregular traffic generated by most nonvoice media. Guaranteed sufficient bandwidth and QoS. 171 © 2003 by CRC Press LLC . LLC Fiber Optics Illustrated Dictionary plate, usually passing through acontrolling grid. The electron beam-emitting end of a cathode-ray tube (CRT). See cathode-ray tube, phototube, photomul- tiplier tube. Cathode-Ray. per field (two of which make up the frame) is 282.5 compared to 242.5 for RS-170a. The effective resolution when conversion 167 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary with raster-based displays is desired is 768 (compared to 640 for RS-170a) 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary to the (undesired) interference affecting that transmis- sion. This ratio is of special interest to wireless com- munications engineers in designing