Fiber Optics Illustrated Dictionary - Part 22 potx

Fiber Optics Illustrated Dictionary ofdifferent sizes, and which may take longer to ex- ecute than the same operation carried out on a reduced instruction set computing (RISC) chip. elsc chips are more common on older architectures. A CISC processor command is translated into micro- code, a series of smaller instructions, which are in turn queued and processed one at a time by a nano- processor. See reduced instruction set computing. Complex Node Representation CNR. In ATM networks, a collection of node-related parameters that provide state information about alogical node. This information is useful in routing. Complex Text Layout CTL. An IETF Human Com- puter Interface (HCI) platform standard. Component Object Model COM. Microsoft's ap- proach to object-oriented programming. The COM is a means for creating components that are reusable across a variety of applications, thus reducing programming time and increasing interoperability across applications. Microsoft's Object Linking and Embed- ding (OLE) provided a subset of the functionality now associated with COM. See Object Management Group. For a more complete discussion of the basic concepts associated with programming objects, see object-oriented programming. Component Software Microsoft's description for object-oriented programming components associated with their Component Object Model. See Component Object Model, object-oriented programming. composite Combined, bundled, aggregated, inter- leaved, entwined, mixed. composite video A color composite video signal is one in which the luminance (brightness) and chrominance (color) are combined, with the chrominance modulated onto the luminance as a subcarrier. The signal may have to be separated by the receiver, depending upon the system. Video game systems that plug into a TV set send out acomposite signal, as opposed to an RGB signal that might be sent to a computer monitor. compound modulation A successive modulation technique in which the modulated wave from one step becomes the modulating wave in the next step. Comprehensive System Accounting CSA. Within the Open Source Software community, CSA is a set of C programs and shell scripts that help administrate individual online accounts. CSA facilitates accounting for users, jobs, daemons, and billing units and provides configuration parameters, accounts sched- uling, and hooks to reporting applications. Thus, CSA makes it easier to monitor usage, frequency, and other access data for administrating and tuning networks and for billing purposes. compress Condense, contract, shrink; reduce in size, transmission time, or byte count. compression The act of reducing, shrinking, or short- ening items or data in order to store or transmit the objects or information more easily. Data compression is based on the premise that most files or transmissions include white spaces, noninformational sections, or redundancies that can be removed without affecting or significantly degrading the meaning or 202 quality of the information when it is decompressed. Compression is sometimes also based on human per- ceptual characteristics or multiple means ofrepresent- ing the same data, some of which may be more space- conserving than others. See data compression, decompression, lossless compression, lossy compression, run length encoding. compression algorithm The computer logic and code designed to automate the process ofsaving or transmitting data in less space or less time than if the data were stored or transmitted raw (unaltered). Com- pression algorithms are used on many types of data (video, still images, sound, text, etc.) and the degree of compression is often tied to the type of data and even the specific character of the particular data being compressed. A compressed file is not always smaller than the original. Compression algorithms may be loss less (the information can be reconstructed to be the same, or to appear the same, as the original) or lossy (the information is reconstructed to be essentially the same as the original, or perceptually similar, but not identical). Compression Control Protocol CCP. Aprotocol for negotiating data compression at both ends of an established Point-to-Point Protocol (PPP) link. CCP was introduced as a standards track protocol in the mid-1990s as a means to configure, enable, and dis- able data compression and to signal errors in the compression/decompression mechanism. CCP is similar to Link Control Protocol (LCP) except that CCP uti- lizes different timeouts, additional codes, and specific PPP Protocol field indicators and may utilize frame format modifications that may have been established with the link. See Link Control Protocol, Point-to- Point Protocol, RFC 1962. Comp Tel Competitive Telecommunications Associa- tion. An association that includes WorldCom and a number of medium-sized communications carriers. Compton scatteringA form of photon scattering that results from stimulation by electromagnetic radiation. The scattering effect is small but important, as it occurs at a wavelength different from the incident radiation, scattering off of loosely bound "stationary" electrons. Thus, for light, aparticle model is more effective at describing the effect than a wave model. In Compton scattering, the scatter angles and energy levels in the scattered photons may be detected/cal- culated. At visible light ranges, the effect is very small, but becomes more apparent at the higher energy levels associated with X-rays or gamma rays. This is useful for telescopic radiation detectors. A Compton scattering telescope typically consists ofa scintillating layer that Compton scatters gamma radiation. The scattered photons then encounter a sec- ond scintillating layer which absorbs them. Phototube detectors assessing the two levels can somewhat determine interaction between the two layers and the associated amount of energy deposited. Unfortu- nately, the Compton relationships don't include information about the angle ofincidence of the incoming photons, so this must be determined or estimated by other means if the source of the radiant energy is © 2003 by CRC Press LLC sought. See Bragg's law, Rayleigh scattering, Thomson scattering. Compton Scattering The Compton effect was studied in the early 1920s by A. Compton andmay beexpressed mathematically as A f - Ai =M =(h/mc) * (1- cosS) where \ is the scatteredphoton and Ai is the incoming (incident) photon and h is Planck's constant. In terms of understanding the nature of light, this was important data confirming the hypothesis of a particle nature of light. Compton, Arthur Holly (1892-1962) An American physicist and engineer who studied X-rays and developed theories and mathematical expressions describing their behavior, including reflection and po- larization effects. He was also a pioneer in obtaining the spectra ofX -rays by the use of ruled gratings, information that was invaluable in determining electronic charge. In 1941, he became chairman of the National Academy of Sciences. Compton is best remembered for having observed and mathematically expressed Compton scattering, a subtle wavelength-shift effect that provided conftr- matory evidence for a particle nature of light. In 1922, he published his observations in Secondary Radia- tions Produced by X-rays. In collaboration with A. Simon, Compton provided further confIrmation of the effect by the coincidence method, describing how individual scattered photons and the electrons off of which they recoiled would appear simultaneously, an idea that required quantum rather than classical physics concepts to reconcile. In 1927, Compton and C. Wilson were coawarded the Nobel Prize in physics. In 1991, NASA named its new space-based gamma radiation observatory after Compton. See Compton scattering. CompuServe, CompuServ Historically, one of the earliest large-scale commercial computer service providers, CompuServe was initiated in 1969 as a time- share subsidiary of Golden United Life Insurance under the name CompuServ Network, Incorporated. In 1986, the service was purchased by H&R Block. By the late 1980s, CompuServe was also beginning to sell services to personal computer users and soon after expanded into the European market. In 1989, CompuServe was one of the pioneering Internet mail relay carriers and, in the mid-1990s, extended its tra- ditional BBS-style dial-up services to include Inter- net access. CompuServe survived the online services shakeouts of the 1990s to become a large, commercial dialup Internet Services Provider (ISP). In 1997, it was bought out by America Online, Inc. (AOL) and posi- tioned as an interactive service brand. In addition to public services, it provides CompuServe-specific services available only to members, including airline res- ervations, stock listings, chat services, etc. computer A logic-processing device, which usually includes temporary or long-term storage and input and/or output devices for interaction with the user. It mayor may not be programmable and mayor may not be constructed with binary architecture (binary computers are prevalent). A computer doesn't have to be strictly electronic, and researchers have explored biological parts or processes for incorporation into computing devices. Quantum computers have been proposed, with science fiction possibilities, but none has yet been devised. However, individual quantum processes have been developed successfully and may someday be incorporated into computers. The most common configuration for digital desktop computers consists ofa central processing unit (CPU) for performing mathematical logical instructions, sometimes cooperating with coprocessing chips for graphics and sound; volatile storage, usually in the form of RAM; read/write semi-permanent storage, usually on magnetic or magneto-optical media; user- interaction input/output devices such as monitors, keyboards, mice, microphones, cameras, speakers, and joysticks; and program instructions in the form of operating systems and applications programs. To enhance the usefulness of basic computers, printers, scanners, modems, and network interfaces have been developed, which communicate through a printed circuit board, or various SCSI, IDE, serial, parallel, USB, Fire Wire and networking ports. Many people make the mistake of assuming the software that runs the system, the operating system (OS), is the computer itself. While it is true that aparticular OS is usually optimized for aparticular platform, operating systems can be adapted to run on many systems. Early computers ran several operating systems (see TRS-80), and the trend is moving back in that direction. Linux, Be, Inc.'s BeOS, and Apple Computer's OS X, as examples, are designed to run on a number of hardware platforms, providing the user the freedom to choose his or her hardware/software combination. Computer and Business EquipmentManufactur- ersAssociation CBEMA. See Information Technol- ogy Industry Council. Computer and Communications Industry Asso- ciation CCIA. A trade organization based in Virginia that represents data processing companies and common carrier service companies. The CCIA provides education and lobbying support to its members. 203 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Computer and Information Science and Engineer- ing CISE. A U.S. National Science Foundation Di- rectorate that promotes basic research and education in the fields of computer information sciences and engineering. http://www.cise.nsf.gov / Computer Control Company The company that originated the Series-16 minicomputers, washing- machine (and smaller) sized 16-bit-register computers that were bought out by Honeywell in the mid- 1960s. See Honeywell Kitchen Computer. ComputerEmergency Response Team CERT. Es- tablished in the late 1980s by the Advanced Research Projects Agency (ARPA), based at Carnegie Mellon University. CERT provides assistance to computer operators wrestling with various network security and operations issues. computer fraud Misrepresentation or theft accom- plished on, with, or with regard to computers. The computer data may itself be the target of the fraudu- lent activities or a computer may be used as a tool to aid in noncomputer-related fraud (as in records theft, spying, or unauthorized access). Unsecured computer data, in the form of accounts, confidential business or investment information, personnel files, etc. is especially subject to tampering. ComputerIncidentAdvisory Capability CIAC. An archive and notices repository posted in conjunction with the Laurence Livermore National Labs Web site to inform the network community about security weaknesses and breaches that might compromise network systems, particularly the Internet. This posting is intended to provide technical assistance to help secure the Department of Energy (DoE) communications systems, but the posted bulletins are open to the Internet community. CIAC was founded in 1989 and is a founding member of the Forum of Incident Re- sponse and Security Teams (FIRST). CIAC provides training, education, technology watches, and trend, threat, and vulnerability data collection and analysis. CIAC publications that are transmitted to other par- ties are signed with a PGP encryption key. Computer Science Telecommunications CST. A pub- lication of the University of Missouri (Kansas City) School of.Interdisciplinary Computing and Engi- neering. Computer Security Institute CSI. A professional organization committed to supporting and educating information technology (IT), computer, and network security professionals, founded in 1974. http://www.gocsi.com/ computer societies, national A complete listing of the world's computer societies is outside the scope of this dictionary, but a sampling of some of the ac- tive and prominent societies that are accessible on the Web helps illustrate the types of organizations that exist and their general goals and priorities with rela- tion to information technologies and computing science. See Computer Societies chart. ComputerSupported TelecommunicationsAppli- cations CSTA. A computer telephony interface standard published by the European Computer Manufac- turers Association (ECMA) in 1992. Work on ECMA 204 telephony standards was carried out by the ECMA Technical Committee TC32. CST A was developed for integrating computers and telephone technology into a unified system, in a process described as Computer Telephone Integration (CTI). CSTAhas been adopted as an ISO standard and is one of the most important international standards for computer telephony for the predictable future. The standard describes information interchange among telecommunications and computer devices. It is sufficiently generic to encompass analog and digital private, public, and combination communications signaling systems, switches, and networks. Initial applications of the standard tend to focus on telephony/database integration and basic automation of services but, since it is a broad-based standard, new types of services and technologies will emerge as it becomes better understood and supported. Computer Systems Policy Project A lobbying organization formed in 1991 to represent those who felt national networks were too oriented toward research and science and not enough toward everyday users. In actual fact, statistics show that a great majority of Internet use is devoted to conventional everyday user traffic, predominantly business and personal electronic mail and file transfers unrelated to research and science. computertelephony integration CTI. Integration of computer database, dialing, and other features, with voice communications through a headset, handset, or other computer peripheral voice transmitting and receiving device. See Computer Supported Telecom- munications Applications, computer telephony. computer-aided dispatch CAD. A system in which the administration of services is aided by a computer. For example, emergency or law enforcement systems may track the location of vehicles and their direction of travel in order to dispatch calls in an efficient man- ner. Similarly, taxi and limousine services can be managed with the aid ofa computer. Billing and mile- age factors may also be stored by the system, and sta- tistical measures tracked in order to enable a company to better manage its resources. computer-aided learning, computer-assisted learning See computer-assisted instruction. computer-aided manufacturing The process of using a computer to directly control manufacturing equipment, such as drilling machines, production lines, bottle cappers, saws, chisels, and any of the fab- rications equipment which normally may have been driven by manual, electrical, or mechanical machines without the benefit of logic programming. One of the best applications of computer-aided manufacturing is integrating the production machines with parametric design software (usually used with CAD) so that objects that are generally the same, but perhaps different in specifics, can be manufactured with the same equipment, under the control of the computer. See parametric design. computer-assisted instruction CAl. Instructional media and techniques used in conjunction with computer software, or entirely by computer software, in © 2003 by CRC Press LLC the form of tutorials, demonstrations, white papers, online mentors and instructors, educational software, tests, multimedia presentations, etc. CAl has been around for decades as a number of instructors were quick to grasp the significance of and opportunities provided by CAl, particularly for individual learning and distance learning. However, the resources and time to provide good educational programming and the prohibitive cost of systems up until recently greatly limited the practical application of these ideas. Computer+Science Network CSNET. CSNET merged with BITNET in 1989 to form the Corpora- tion for Research and Educational Networking (CREN); CSNET was discontinued in 1991. computerTV See telecomputer. Computists International CI. Aprofessional association for information science, artificial intelligence, and computer science researchers. CI provides information on industry trends, leading edge technologies, research, and job opportunities. CI publishes a weekly Computists ' Communique reporting on artificial intelligence, neural networks, genetic algorithms, machine learning, natural language processing, fuzzy logic, and computational linguistics. See artificial intelligence. COMSAT Corporation Originally created by the u.S. Congress, COMSAT merged with Continental Telephone to form COMSAT Corporation, an international provider of satellite communications and networking services. COMSAT operates through the INTEL SAT and Inmarsat systems and is currently the largest user of both systems. COMSAT operates the COMSAT Laboratories for research, development, and technical consultation in pioneering satellite communications technologies. http://www.comsat.com/ concatenate To link, chain, or otherwise place adja- cent objects or structures end-to-end. Thus, a female RCA plug can concatenate two RCA cables with standard male ends. A 2-port 25-pin data switcher can be used to selectively concatenate one or the other of two 25-pin cables (e.g., serial cables). A software "join" utility can concatenate two files, one after the other (as opposed to merging one file into another). See daisy chain. concave Dished in, hollowed out, bowl-shaped (on the inner surface), or otherwise smoothly curving or arching inwards in two or three dimensions. Many optical components and networking structures have concave shapes, including resonating cavities, lenses, reflectors, parabolic antennas, etc. See parabola. Con- trast with convex. concentrator A point or device at which a number of elements are brought together either for simplic- ity of cabling and management, or to more efficiently provide a means to allocate shared resources. Astar topology network is a type ofconcentrated configuration with a hub negotiating communications among the connected systems. Aprinter room with several kinds of printers available to the general office is another type of concentration point for general network services. The concentrator itself may be a smart device, like a router, which processes the incoming infonnation and sends the task or communication to the best destina- tion or it may simply work on a frrst-come, first-serve basis. A patch panel is a type of cable concentrator in the sense that it brings together the connecting points of a large number ofindividually cabled systems, usually to facilitate reconnections in different configu- rations. A modem pool is aconcentrated assembly of individual modems, brought together in one facility, room, or closet, for easy access, configuration, and maintenance. See condenser. concentrator, optical A device, such as a lens, that concentrates electromagnetic radiation into a higher energy level or smaller physical space. This is useful for increasing luminance, collimating beams, or chan- neling light into narrow openings such as the endfaces of fiber optic lightguides. concentric In geometry relating to fiber 9ptics, two or more broadly circular or rotating structures in the same general plane with a common center point or rotational axis. Thus, a bull's eye target comprises a series ofdifferently sized concentric circles. Ashaft within a rotating cylindrical tubing is concentric along the access of the shaft. Cable assemblies, with layers comprised of cylindrical fiber-conducting cores, cladding, tubing, aramid yam, and outer armoring sheaths are concentric along the perpendicular plane to the axis of the length of the fiber core - in cross-section, the assembly will resemble a target. Concentric structures are generally not concentric from every viewing angle. Just as a flat target has concentric circles only on the front and not on the side, the axis of reference is important. Concentric- ity may be associated with stepped or curved structures, as in Fresnel lenses or other types of curved, ridged components. However, they are only concentric in those planes in which the ridges share a common axis. In other words, they are concentric at the points where a knife, slicing down through all the layers, would pass through the shared center of all the reference components along the shared axis. Only an assembly of two or more perfect spheres of different sizes, with their radii sharing a common center, would be concentric in any given plane that passes through the center. Technically the structures don't have to be circular to be concentric. A target could be comprised of different-sized squares rather than circles, as long as they share a common center point, but in practical applications concentricity is often associated with roughly circular or spherical components, especially those that rotate within one another. concentricity error In fiber optic lightguides with two or more component layers (e.g., cladding sur- rounding the core), which may not be perfectly circular at any given point, and thus not perfectly concentric, the ratio of the cladding to the core, which has fine tolerances for optimum performance, may not be ideal. At this point, the reflection of the light beam off the cladding and through the core may be 205 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Computer Societies - Sample List Organization Abbreviation/Description Australian Computer Society ACS Per capita, one of the world's largest computer societies, established in 1966 in a merger of state-based computer societies. The ACS studies, supports, and promotes professional excellence in information technology. See ACSnet. http://www.acs.org.au/ British Computer Society BCS A professional society and registered charitable institution for supporting the field of information systems engineering, founded in 1957. The BCS is also a licensed engineering institution with accreditation-granting authority. http://www.bcs.org.uk! http://www.infj.ulst.ac.uk! bcs/ Computer Society ofBermuda CSB A nonprofit organization for fostering knowledge and applications in information technologies in Bermuda, founded in 1975 and incorporated in 1986. http://www.csb.bm/ Computer Society ofIndia CSI Founded in 1965, the CSI is committed to promoting the interchange of information and the advancement of the theory and practice of computer technologies and professions. http://www.csi-india.org/ Computer Society of South Africa CSSA A not-for-profit professional corporation dedicated to the support and education of its members in various chapters throughout the region. http://www.cssa.org.za/ Computer Society ofSri Lanka CSSL Formed in 1977 to support and promote research and professionalism in the information technology field. http://www.ccom.lkJcssl/ Jamaica Computer Society JCS A communications and education body of Jamaica which seeks to promote the efficient and effective use of information technologies in Jamaica. http://www.jcs.org.jrnl Jordan Computer Society JCS A nonprofit organization for promoting the computer profession, founded in 1986. http://www.nzcs.org.nz/ Hong Kong Computer Society HKCS A nonprofit professional organization promoting education and applications in information technologies in Hong Kong, founded in 1970. http://www.csb.bm/ IEEE Computer Society IEEE A highly prominent American organization descended from the Subcommittee on Large-Scale Computing of the American Institute of Electrical Engineers (AlEE), founded in 1946. The AlEE and the Institute of Radio Engineers merged in 1963 to become the Institute of Electrical and Electronics Engineers (IEEE). The IEEE has members around the world. It promotes education and professionalism in a broad range of computing technologies and is responsible for the development of many telecommunications and computing standards. http://www.computer.orgl http://www.ieee.orgicshome.htm Irish Computer Society ICS The ICS supports and promotes a broad range of information technologies through education and member services. It was founded in 1967. http://www.ics.ie/ Kuwait Computer Society KCS A Kuwaiti Public Welfare Institution, founded in 1982 as the Kuwaiti Society of Computers, renamed in 1990. The KCS promotes education and professionalism in computer sciences and information technologies. http://www.paaet.edu.kw/Info/HomePage/adel/kcslkcs.hnn Lithuanian Computer Society LIKS An independent society of software users, amateurs, and professionals in informatics and computing science, officially registered in 1990. http://www.liks.1t/ Malaysian Computer Society MCS A society that promotes computer literacy in Malaysia, founded in 1998. http://www.geocities.com/EurekaiConcourse/2008/ Mauritius Computer Society MCS The MCS promotes personal and professional development and computer literacy in Mauritius. http://ncb.intnet.mu/mcs.htm New Zealand Computer Society Inc. NZCS Promotes and fosters education, qualification, and professional development in information processing. http://www.nzcs.org.nz/ Norwegian Computer Society NCS An open, independent, self-financed society for promoting awareness and the advancement of information technologies for business and society. http://dataforeningen.no/ncs/ Singapore Computer Society SCS Singapore's largest information technology professional body, founded in 1967. The SCS promotes personal development and industry leadership in information technology. http://www.scs.org.sg/ Syrian Computer Society SCS A nonprofit national organization of scholars and engineers, based in Damascus, founded in 1989. The SCS furthers information technologies in Syria. http://www.scs-syria.coml 206 © 2003 by CRC Press LLC hindered by deviations from aperfect circle and corel cladding ratio. See concentric, total internal reflection, critical angle. concurrent Functioning, processing, or operating at the same time; parallel, in conjunction with; coexist- ent, simultaneous, synchronous. concurrent programming Techniques and associated notation systems for parallel processing imple- mentation. Distribution, synchronization, prioritizing, and signaling are important aspects of concurrent programming. For example, computer graphics special effects rendering is computing intensive, and farm- ing out various objects to various processors or work- stations, and then combining them in one frame when each is rendered, can greatly decrease the time it takes to create each image (called render farms). Not all types of operations benefit from concurrent programming. The overhead involved in setting up the distribution and coordination of the data must be smaller, in proportion to the effective processing that occurs, to make it worth processing in parallel. concurrent site license In the software industry there are a number of common schemes for assigning software use rights. Exclusive operation on only one machine at a time is the most common, but it is also possible to get concurrent licenses that permit a specified maximum number of users to access the software at anyone time from a networked server, or that permit up to a specified number of users (five is common) to install the software on individual worksta- tions. condenser An apparatus that concentrates or con- denses a beam, ray, wave, or collection of particles. In the process of concentrating asubstance, wave, or particles, the condenser may also secondarily store them, as in electrical energy. A device that focuses radiant energy, such as a lens for concentrating light or a parabolic antenna for concentrating satellite waves, can be considered a basic type of condenser. See concentrator; condenser, electrical. condenser, electrical Condensers range widely in complexity and construction. They are used with a variety of types ofelectrical apparatus, for example, spark coils. Condensers employ adielectric, that is a material that doesn't readily conduct direct current (DC). Dielectrics vary from paper to ceramic or glass, with the better insulators being used in higher volt- age applications. A Leyden jar is one of the earliest condensers used for concentrating and storing electrical energy. In the Leyden jar, the glass acts as the dielectric. Avariation on the same idea, using glass plates in a rack rather than ajar, were used for early wireless condensers. See capacitor, condenser, Ley- den jar. conditioning The processing of current to make it suitable for specific tasks. Some electrical appliances can tolerate variations in current or noise, while others are very sensitive to variations and noise, particularly small electronic components, requiring that the raw current that may come from a wall socket or other source frrst be conditioned to meet the needs of the device. See AC to DC converter. conductance The ability, readiness, inclination, or disposition ofa material or system to carry an electrical current, expressed in the practical unit mho (ohm spelled backward). The reciprocal ofelectrical resistance. See conductor. conductivity method A pioneer experimental ~~~;{~r~;l~~1~;~:~~~:~~~~~~~~~ '. before Marconi demonstrated practical applications ofwireless communications. Terminals of strong bat- teries were set up in series from a sending key, grounded at a distance of about fifty feet apart. A sym- metric arrangement was set up at the receiving end, except that it used atelephone receiver or galvanom- eter. Other researchers experimented with this method, but little documentation of their efforts is available. See Preece, William; Steinheil, K.A. conductor Amaterial that readily carries an electrical current or heat. Some metals make especially good conductors (e.g., silver, copper, gold, alumi- num) and are widely used in the manufacture of wire. Less conductive materials, such as rubber, used in specialized parts such as gaskets and seals, are sometimes impregnated with metal to increase their conductivity, while still retaining attributes that are dif- ficult to achieve with metal alone. The tenn conductor originates from Desgauliers in the 1730s. Con- trast with insulator. conduit 1. In its most basic sense, a channel for di- recting physical objects or virtual data along its path. 2. A liquid conduit is a pathway often used for tem- perature regulation, dispersion of lubricants, or chan- neling of fluids from one area to another. See duct. conduit, wiring 1. Atubular, hollow, physical pathway providing a channel for materials installed inside or directed through its core. Plastic, metal, and ceramic are common conduit materials. 2. A pipe that provides aprotected pathway for wire, cable, or other conductive materials. Conduit is commonly used to run wires in a building and may also include insula- tion, color coding, and other attributes to protect or identify its contents. Conduit can be a good way to hedge against obsolescence, since it can be rethreaded more easily than cables that have been attached directly to the structure of a building inside its walls. cone of silence See zone of silence. Conference Europeenne des Administrations des Postes et des Telecommunications (European Con- ference of Postal and TelecommunicationsAdminis- trations) CEPT. An international standards body rep- resenting telecommunications providers in most na- tions other than Japan, Canada, U.S., and Mexico. It cooperates with CEN/CENELEC. See El. configuration Setup, organizational structure, architecture, topology, assemblage, physical and logical parts and interactions taken as a whole. congestion indicator In ATM networking, a traffic flow control signal to reduce the allowed cell rate (ACR) in order to reduce the likelihood of increasing congestion. The information is contained in the RM cell. See cell rate, leaky bucket. 207 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Congestion Manager CM. A network end-system module that enables applications to adapt to network congestion and enables a suite ofmultiple concurrent streams from a sender to a receiver with the same congestion properties to perform congestion avoid- ance and control. Congestion Manager was submit- ted as a Standards Track RFC by Balakrishnan and Seshan in June 2001. The framework supplied by Congestion Manager in- tegrates congestion management across all applications and transport protocols. It maintains parameters and exports an API with information about network characteristics and enables applications to pass information to the CM, to schedule data transmissions, and to share congestion information. Use of the CM re- quires explicit consent of the CM through the API. CM may be elected for use on best-effort network systems that have well-behaved applications with their own independent per-byte or per-packet se- quence number information and use the API to up- date the CM's internal state. See RFC 3124. conical array antenn'a An antenna that can receive arange of VHF signals through a central rod with re- flector elements extending out at right angles to the support rod and, at the other end, forward-oriented driven elements fanned out more or less from a single connection point on the rod. conical monopole antenna A vertically polarized, broadband antenna shaped like a cone with the narrow end oriented towards the top. The frequency response is related to the size and angle of the cone. conical scan In radar antennas, a circular scanning motion, often used on aircraft, that provides more complete information on the location and characteristics of the object of the scan. The conical scan can provide angular information. Connect 918 A Macintosh and IBM-licensed PC- based videoconferencing product from Nuts Tech- nologies that supports video, audio, whiteboarding, and screen sharing over analog, Switched 56, ISDN, and Ethernet networks. It uses ITU-T H Series and GSeries Recommendations standards and encoding. See Cameo Personal Video System, CU-SeeMe, IRIS, MacMICA, ShareView 3000, VISIT Video. Connected,Limited Device Configuration CLDC. A Sun Microsystems Java specification used by a number of major wireless telecommunications providers as a guideline for manufacturing and programming small Java-enabled communications devices. The audience for the CLDC specification is the Java Community Process (JCP) expert group and afore- mentioned developers. Participants include prominent network technology companies such as Nokia, Ericsson, Fujitsu, Sony, America Online, et a1. The "Limited Device" designation applies to relatively slow CPU, limited-resolution, limited-memory devices that are becoming prevalent as mass-produced hand-held assistants, including palm-top computers and schedulers, and advanced-feature cellu- lar phones, etc. Thus, CLDC is a minimum-foot- print specification for connected devices, devices that can interface with a computer or wireless network. 208 The full specification is downloadable free from Sun Microsystems' Web site. connection 1. A system or circumstance of physically or logicallyjoined entities, objects, or processes. An electromagnetic connection is one in which current from one system can pass into another, either through a splice, jack, plug, or other connector, or by a spark or induction system. 2. A wireless connection is one in which a signal is transferred without a visible physical connection. Wireless connections typically are based upon the transmission ofsound or electromagnetic waves that originate in atransmitter (which commonly includes or is associated with a wave gen- erator) and terminate in areceiver which mayor may not convert the signals into visual or audio forms that may be directly perceived by humans. connection management controller CMC. Works in conjunction with abroadband integrated gateway (BIG) to take data from incomingATM cells for processing and routing. See broadband integrated gateway,HFC. connection protocol The software protocol that ne- gotiates a pathway for a transmissions connection session. connection-oriented A type of communication in which the sender/receiver connection is established prior to transmission, as in a phone call. This may sound like a logical way to do things, but a substan- tial amount of network traffic does not follow this model. In sending an email message, for example, the message will be sent irrespective ofwhether the receiver is online at the time the message is sent. Then, if too much time elapses, or a certain number of at- tempts to deliver the message have failed, it will be returned to sender. Modem communications are connection-oriented. If there is no answering handshake at the other end of the transmission, no transfer of data takes place. Contrast with connectionless. Connection-Oriented Transport Service COTS. A connection-oriented, end-to-end network communication service. COTS involves initializing the service, establishing a connection, transferring data, releas- ing the connection, and general cleanup associated with the release of the connection such that it may be reused, unbound, or closed. When a COTS session is initialized, it enables the COTS driver and associated application to be bound with a specific transport entity. Various buffer-handling or status utilities may be used during the connection. In the Open Sys- tem Interconnect (OSI) model, connection-oriented network services are implemented by using the Con- nection-Oriented Network Protocol (CONP) and the Connection-Mode Network Service (CMNS). connection-related function In ATM networking, a traffic management and policing function related to a network element (NE) where connection-specific functions are carried out. connectionless A type of network transmissions architecture in which the data is sent without first establishing that the receiver is connected and available to receive transmissions. Large distributed computing environments frequently employ connectionless © 2003 by CRC Press LLC services. In contrast, phone calls and modem data transfers are connection-oriented end-to-end communications. Contrast with connection-oriented. Connectionless Broadband Data Service CBDS. In ATM networking, a high-speed packet-based connectionless service similar to SMDS (Bellcore) that is defined by the European Telecommunications Stan- dards Institute (ETSI). CBDS is appropriate for networks requiring high-volume, high-speed transmission rates and thus is favored for high-end graphics and publishing, videoconferencing and streaming, and scientific research applications. CBDS is favored over private lines or permanent virtual circuits (e.g., Frame Relay) for some inter-business communication needs. Commercial implementations of SMDS or CBDS support multicasting and most major network protocols (TCP/IP, SNA, AppleTalk, etc.). CBDS can be integrated with existing Ethernet, Token-Ring or FDDI local area networks (LANs). At the present time, CBDS is more widely installed in Europe than North America. Refer to the ETSI ETS 300 series documents for specifications. Connectionless Transport Protocol CTP. Aproto- col that provides a means to send to a recipient that mayor may not be connected to the network at the time the data is transported. CLP allows end-to-end transmission addressing and error control, but does not guarantee delivery. connectivityA property of mechanical and electronic systems that allows them to interconnect with other devices or systems for the purposes of transmitting or relaying information or signals. While connectivity generally refers to physical connectivity, the increasing importance of data in communications and hardware configuration has extended the term to software as well. When systems or devices can be readily interconnected in terms of hardware and software, they are said to be compatible. See connection. connector 1. A device to join or combine two or more objects. When circuits are coupled with a connector, the two systems or obj ects are usually intended to communicate in the same way (otherwise the connector is usually referred to as an adapter). The connector may be incorporated into the device being connected or may be a separate item. See adaptor, gender changer, jack. 2. In a flow chart, a connector is a sym- bol that can be used to indicate ajoin in a flow, or the divergence of the flow into additional paths. See ST- connector. Connon, John R. (1862-1931) A Canadian inventor and historian who devised various innovative mechanisms, including a type of dynamo, and who was granted a first patent for a cinematic camera in the late 1880s. Connon worked together with Rudolph Stirn, a German inventor, to develop panoramic technology. Connon's innovative camera could photograph a continuous image, without seams, while rotating 360 degrees (a similar camera was patented by M. Garella in England in 1857 but the au- thor wasn't able to determine if the earlier camera was seamless). See panoramic camera. Sampling of Standardized Connectors Avariety of common, standardized computer, phone, and video connectors. 1. 9- to IS-pin D-shaped computer data adapter 2. 25-pin D-shaped null modem data adapter 3. RJ-II phone line splitter/joiner 4. and 5. stereo sound adapters 6. and 7. coax F and BNC video adapters I 8. RCA video/audio splitter/joiner 9. RCA video/audio cross connector A selection of video and data connectors, oriented to show the connectingpins. 1. 6-pin mini-DIN computer connector 2. RJ-45 1OBase-T computer network connector 3. video BNC coaxial cable connector 4. audio or composite video RCA connector 5. Super-VHS (S-Video) video connector 6. SCSI-2 50-pin computer data connector 7. 25-pin D-shaped computer data connector 8. 50-pin flat SCSI data connector Conrad, Frank (1874-1941) An American broad- caster who began as call sign 8XK in his Pennsylva- nia garage, which was later licensed as the history- making KDKA radio broadcast station. Conrad was also an avid inventor, with dozens of patents to his credit. His interests ranged from telegraphy to moving picture technologies. In 1919, he patented a ra- diotelegraph device (U.S. #1,314,789), followed by a wireless telephone (#1,528,047) in 1925. By the late 1920s, Conrad was designing various types of tele- phones, and in the mid-1930s his interests turned to television and motion picture electronics. The Frank Conrad Garage (where it all began) is an official pres- ervation project of the Save America's Treasures effort. See KDKA. consecutive Continued presentation of objects, data, or actions one after the other; successive, sequential, 209 • © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary following. A distinction may be made between sequential and consecutive in that sequential implies that there are no gaps between succeeding steps, whereas consecutive implies there may be gaps or delays in successive presentations, depending upon the nature of the information of actions. For example, it would not be unusual to say a person was working on the computer on consecutive weekends, but the phrase "sequential weekends" would not normally be used, as there is aweekday gap between each week- end. Sequential events are always consecutive, but consecutive events are not always sequential. If this is confusing, think of the fact that a square is always a rectangle, but a rectangle is not always a square. See concurrent, parallel, sequential, serial. Consent Decree, Dell A late 1990s judicial decree barring Dell Computer Corporation from telemarketing computer systems bundled with software that wasn't ready to ship. The proceeding was important because software was relatively new and established legal protections were still being worked out for new technologies. In this case, Dell promoted the Dell Software Suite as being bundled with Dimen- sion computer systems. Consumers on the whole received the system without software and were not of- fered the opportunity to consent to the delay or can- cel orders for a prompt refund. The Federal Commu- nications Commission (FCC) charged that Dell vio- lated the Mail Order Rule. Since Dell is considered a major personal computer vendor, and vendors are focused on being first-to- market (which can be influenced by the readiness level of the software), this ruling can potentially af- fect many communications technology vendors, as they increasingly rely on software operating systems and utilities to promote their hardware products. Consent Decree, MCI and British Telecom A 1994 decree in which British Telecom's acquisition of an interest in MCI Gointly called Concert Communica- tions Corporation) were addressed as to the competitive effects of the merger. Amodified decree was en- tered into in 1997, as a result of British Telecom's plans to acquire the remaining assets ofMCI. When British Telecom sold its interest in MCI to WorldCom, and MCI sold Concert Communications Corporation to British Telecom, a motion to terminate the consent decree was tendered in 1998. Consent Decree, Microsoft A 1995 decree with a 78- month duration involving Microsoft Corporation. Microsoft is asignificant software vendor alleged by a number of competing vendors as engaging in mo- nopolistic and unfair business practices. In this decree, Microsoft was enjoined not to enter into license agreements for operating system-related products with a duration exceeding one year and license agreements which would restrict OEMs from licensing, selling, or distributing non-Microsoft operating system software products. In later competition for market dominance of Web browser software, the antitrust division of the Justice Department alleged that Micro- soft was not keeping to the terms of the previous agreements. The result was a long and complex anti- 210 trust investigation against Microsoft in the late 1990s continuing into the 2000s. Consent Decree, SprintAdecree in 2000 between the Federal Communications Commission (FCC) and Sprint Communications Company, LP, regarding the illegal practice of slamming - switching consumers' long-distance telephone services without their consent. Sprint voluntarily notified the FCC of the practice, after a number of slamming enforcement actions taken earlier the same year by the FCC against other companies, and agreed to avoluntary monetary con- tribution in addition to returning consumers to their preselected carriers, terminating the agents involved, and implementing a stronger slamming prevention and detection program in the firm. Slamming was not a new problem at the time. In an earlier consent decree in 1996, MCI agreed to vol- untary contributions for slamming, indicating that the practice and the problems of its enforcement are longstanding. Consent Decree of 1956 Ahistoric agreement between the Justice Department and American Tele- phone and Telegraph (AT&T) to separate Northern Electric (later Northern Telecom) from Western Elec- tric. In spite of the limited settlement, the Federal Communications Commission (FCC) received many complaints from manufacturers over the next two decades about AT&T refusing to buy or refusing to permit their subscribers to buy new improved telephone technologies. This situation lead to the Con- sent Decree of 1982. Consent Decree of 1982 A landmark historic proceeding, this consent decree involved the divestiture of AT&T that took place in the mid-1980s under the direction of Judge Greene. It is now more commonly known as the Modified Final Judgment (MF J), since it was amodification of the Consent Decree of 1956. See Modified Final Judgment for a fuller description. console 1. Floor-standing cabinet, typically holding consumer broadcast receivers (radio, TV). 2. A primary operations physical unit that holds main electronic controls and monitors (such as lab equipment, medical monitors, industrial plant operations equipment, etc.). console, computer operationsAcomputer terminal for monitoring/controlling computer operations, printers, etc. On a secure network, the operating console is often password-protected to control access and may even be locked in a separate room to prevent access or physical theft. The main server sometimes serves also as the console, although on larger systems the server and the console may be separate systems. console, telephone A primary multiline telephone unit used by an operator to answer and route calls (a replacement for the old physical cord-and-stereo- jack-style switchboards). These come in a wide variety ofconfigurations. Some are programmable by entering letters, features, and numbers through the keypad, which may further be displayed on a small character display. See PBX. consoleless operation Automated operations or routing, an option for companies whose needs are simple © 2003 by CRC Press LLC enough that they can function without a central unit, or without the expertise of an operator. See PBX. Consortium for Audiographics Teleconferencing Standards CATS. A nonprofit organization, based in California, that promotes acceptance and development of audiographics teleconferencing standards. Audiographics teleconferencing in its ideal form is the simultaneous realtime use of images and sound, in a cooperative environment, by participants in different locations. constant angular velocity CAV. A playback mode for magnetic and optical discs in which the disc ro- tates at a constant speed. A CAV disc generally re- quires more space on the disc to hold the same information as can be stored on a constant linear velocity (CLV) disc, but CAV format has the advantage of providing frames that can be viewed individually in 'freeze frame' mode as still images. See constant linear velocity. constant bitrate CBR. InATM networks, a cell rate traffic flow class of service (CoS) category that supports a constant or guaranteed rate of transport, and circuit emulation. Constant bit rates are important for types of communications that require synchronization of signals at the receiving end. For example, synchronization of sound and audio in a videoconferencing application is important, as unacceptable delays might occur if related cells are not arriving at the same time. See cell rate. constellation 1. A group related by proximity and physical or conceptual connectivity (such as work- stations, celestial bodies). 2. In GPS, the set of satellites used in a position calculation or all the satellites within communications range ofa GPS receiver at a specific time. See Global Positioning Service. Constellation Communications, Inc.A U.S based commercial provider of satellite communications services. Constellation is developing a low Earth orbit (LEO) system comprising 46 satellites called the ARIES satellite system. Eleven ARIES satellites will be placed in circular equatorial orbits at 2000 kilo- meters, and 35 will be divided into seven circular in- clined orbits at the same altitude. consult To seek advice, opinion, or information from reference materials, or from another person, presum- ably with expertise in the area of inquiry. consultant Professional or other expert offering advice or infonnation services, usually specialized. Consultation Hold A surcharge phone service or multiline subscriber service that enables the operator to put an incoming call on hold while engaged in another call. Consultative Committee Telecommunications CCT. A three-nation industry trade association that promotes trade expansion and the evolution of telecommunications equipment and services within NAFTA and North and South America. The CCT represents more than 50 industry telecommunications equipment and services suppliers, as well as regula- tory and certification agencies. CCT liaises with CITEL and serves as industry advisor to the NAFTA Telecommunications Standards Subcommittee. Consumer/Disability Telecommunications Advi- soryCommittee C/DTAC. A Committee of business, academic, public, disability, and minority represen- tatives established by the Federal Communications Commission (FCC) in November 2000 under the pro- visions of the Federal Advisory Committee Act. Three working groups focus on Consumer Protection and Education, Access by People with Disabilities, and Availability and Affordability of Telecommunications Products and Services. C/DTAC frrst met in an open meeting in March 2001 to discuss the telecommunications needs of consumers and various underserved populations, with the meeting set up to be broadcast on the Internet. http://www.fcc.gov/cib/cdtac contact A point in a circuit, usually at a junction, binding post, or terminal, where other parts of the circuit interconnect or are attached. contention Competition for the same space or resources; disagreement over the allocation of resources with the implication that each of the disagreeing par- ties has some desire for or stake in the resources. Contention can be a problem on systems where the demand for resources outstrips supply, especially if there is no mechanism for resolving contention, but contention is not always unexpected or undesirable. On networks, there is constant contention for resources, including computing power, routes, Internet access, printers, monitors, scanners, and modems. This is considered part of the normal operation ofa network and is managed by a variety of strategies, including prioritization, overflow handling, buffer- ing, polling, queuing, batch processing, packet rerout- ing, and timeouts. In both linear and parallel processing systems, different resources may be assigned to different servers or groups of systems to prevent contention delays and facilitate arbitration oflimited resources. Contention mechanisms may be deliberately initiated in situations where there are multiple backup systems. F or example, if a printer on a network fails, the remaining printers may compete for permission to complete the task and the original printer may stand down (or not participate at all if it has failed or been dis- connected). See queue, queuing theory. continuation of message COM. In AIM networks, a status indicator used in the asynchronous transfer mode (AIM) adaptation layer (ATM AL or AAL) to indicate that the cell is a continuation ofa communication that has been segmented, that is, broken up and sent in different sections, sometimes over different pathways. See asynchronous transfer mode. Continuous Redial A subscriber surcharge or bundled telephone service that enables the caller to redial a number that was found to be busy while making or receiving other calls. Ifa number is busy, the caller hangs up and dials *66 (in N .A.). The phone service will continue to try to connect with the busy number for up to 30 minutes. If the call connects, the caller is notified with a distinctive ring and can pick up the phone and take the call. Dialing *86 will terminate the continuous redial. 211 © 2003 by CRC Press LLC . applies to relatively slow CPU, limited-resolution, limited-memory devices that are becoming prevalent as mass-produced hand-held assistants, including palm-top computers and schedulers, and advanced-feature. video connector 6. SCSI-2 50-pin computer data connector 7. 25-pin D-shaped computer data connector 8. 50-pin flat SCSI data connector Conrad, Frank (187 4-1 941) An American broad- caster who began as call sign 8XK in his Pennsylva- nia garage, which was later. Company The company that originated the Series-16 minicomputers, washing- machine (and smaller) sized 16-bit-register computers that were bought out by Honeywell in the mid- 1960s. See Honeywell Kitchen Computer. ComputerEmergency

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