C C A highly structured portable language developed by Bell Laboratories and used in the development of the UNIX operating system. C band Portion of the electromagnetic spectrum (4GHz to 6GHz), used heavily for satellite transmission. C conditioning Type of line conditioning that controls attenuation, distortion, and delay distortion so they lie within specific limits. C++ An extension to the C language, designed by AT&T C-BASIC Commercial BASIC. C-BITS Control bits. CA See collision avoidance cable Insulated conductors covered by a flexible water-proof sheath. cache memory A high-speed auxiliary memory used to buffer data transmissions between fast devices and slower main memory or storage devices. CACS Customer administration center system. CAD 1. Computer Aided (or Assisted) Design or Drafting; using computers to design products or architecture. CAD design is based on vector graphics which can be mathematically manipulated for precision. 2. Computer Aided Dispatching. CAD/CAM Computer-Aided Design/Computer-Aided Manufacturing. CADAM Computer-graphics augmented design and manufacturing. CADD Computer-Aided Design and Drafting. CAE 1. Computer-Aided Engineering. 2. Common Applications Environment; founded on the POSIX 1003.1 specification. CAI Computer-Aided Instruction. CAL CRAY Assembler Language (CRAY Research). CalComp California Computer Products. call accounting system A device that tracks outgoing calls and records data for reporting. See also call detail recording (CDR) and station message detail recording (SMDR). call blocking The restriction of extensions from making calls to other extensions with the same option by the attendant activating this feature. call center A business environment that handles a high volume of incoming calls, with multiple agents responding to calls. Typically equipped with ACDs or call sequencers, call centers are characterized by homogeneous calling traffic and anonymity (i.e., any call can be answered by any agent). call detail recording (CDR) See station message detail recording. call directing code (CDC) A character string used to address a terminal for automatic routing of messages in teletype systems. call distribution See uniform call distributor. call distributor See automatic call distributor. call diversion A device that intercepts calls from a certain number and connects them to a different, pre-determined line. call forwarding -- all calls The user instructs the PBX, usually by dialing an access code followed by the number to which calls are to be forwarded, to ring another station. Calls directed to the user's number are automatically sent to the reassigned number. See also attendant call forwarding setup and cancel. call forwarding -- busy When a user extension is busy, all calls directed to that station are forwarded to the attendant or a selected extension within the PBX. call forwarding -- do not answer If the original station is not answered within a specific period of time, the call is automatically directed to another location. call forwarding -- follow me See call forwarding -- all calls. call monitoring Circuit allowing for the listening in on the attendant's conversation in order to determine the quality of the attendant's responses to customers. call park A feature that enables calls to be transferred to a busy extension; the call can be connected to the extension when it is free. See also camp-on. call pickup Calls directed to one station can be picked up by another station line within a preset pickup group by dialing a special code. call processing The sequence of operations performed by a switching system from the acceptance of an incoming call to the final disposition of a call. call progress tones Audible signals returned to the station user by the switching equipment to indicate the status of a call; dial tones and busy signals are common examples. call record All recorded data pertaining to a single call; often a PBX feature. call restriction override Deactivates call restriction feature. call restrictor Equipment inserted in an outgoing dial trunk that restricts calls to forbidden or unauthorized codes. call selection The attendant can answer calls either in the order in which they arrive or by selecting a specific call type. call splitting A feature that allows an attendant to speak privately to a called party without outside or local party connection. call status indication See line status indication. call transfer See transfer. call transfer with consultation hold See three-way conference transfer. call waiting A busy station receiving another call is notified by a tone burst while the new call is held; the station user can either hang up to receive the new call or place the existing call on hold and alternate between the two calls. See also receiving calls. call waiting indicator Lamps on the station or console indicate that incoming calls are in queue. A steady lamp indicates that less than a specified number of calls (usually five) are waiting, and a flashing lamp indicates that more than five calls are waiting. call, hold See hold. call, local See local call. call, lost A call that cannot be completed because of blocking. call, national A toll call to a destination outside the local or extended service area of the calling customer but within the boundaries of the country in which the customer is located. call, toll Any telephone call that is subject to a charge for connection to a destination outside the local service area of the calling station. call-back modem Modem that stores one or more passwords and telephone numbers. When a call is received, the modem prompts the user for a password, hangs up, and redials the pre-programmed telephone number associated with the password. callback queuing When outgoing calls cannot be completed due to busy trunk groups, the user's extension rings when a nonbusy trunk is available, signalling that the call can now be placed. called number The telephone number called, including the area code, central office code, and line number. called party The subscriber requested by the calling party. calling number The telephone number from which a call originates. calling party Subscriber that originates the call. calling party identification A service that tells the person being called the number calling them. CalREN California Research and Education Network, a project formed to stimulate the development of innovative high-speed telecommunications applications and services. CAM 1. Computer-Aided Manufacturing. 2. Communications Access Method (Unisys). 3. See content addressable memory. CAMA See centralized automatic message accounting. camp-on A feature that allows calls to be transferred to a busy extension; the call can be connected to the extension when it is free. camping See queue. can flash A feature that allows extension users to flash the switchhook while connected to an incoming or outgoing trunk, thus enabling the trunk call to be transferred, held, parked, or added to a conference call. CANDE Command and Edit Language (Unisys). CAP (carrierless, amplitude and phase modulation) 1. CAP enables the implementation of high-speed transmission over standard copper subscriber loops. 2. Competitive Access Providers. 3. Computer-Aided Programming. CAR 1. Computer-Assisted Retrieval 2. Channel Address Register. card (circuit) The board that is used for mounting an electrical circuit. card cage In microcomputers, a supporting structure that generally holds up to nine printed circuit cards. carriage 1. A printer or typewriter mechanism that holds the platen and controls paper feeding and movements. 2. In jukeboxes, the hand on the robotic arm that grasps and moves the disk to or from the storage slot, disk drive, or mailslot. Also called the picker. carriage paper width The limit of the width of a line in word processing. The carriage paper width is usually two inches less than the paper width - one inch on each side. carriage return The act of moving from one line to the next. See return key. carrier (CRX) A steadily-transmitted frequency that can be modulated or impressed with a second (information-carrying) signal. carrier signaling Voice circuits sometimes use a telegraph carrier on one of the voice channels to carry all the associated supervision and signaling circuits; others may use a signaling frequency within the voice band (in-band signaling), or in the guard band (out-band signaling). carrier system Provides for several communications channels over a single path. carrier, communications common A company that is regulated by appropriate local, state, or federal agencies to provide communications services to the general public. Carrier-Sense Multiple Access with Collision Avoidance The network-access method used by Apple's LocalTalk networks, among others. In a CSMA/CA environment, a primary workstation attempting to transmit data sends a request-to-transmit signal to a secondary workstation. When the sending workstation receives a clear-to-send signal from the receiving node, it begins to transmit data. Carrier-Sense Multiple Access with Collision Detection The network-access method used by Ethernet networks. In a CSMA/CD environment, all network nodes must contend for access to the transmission medium. If two nodes attempt to transmit data simultaneously, the transmission session is aborted. Both nodes attempt to retransmit after waiting for a specified period. carrierband Single-channel broadband. Carterfone decision Landmark FCC decision in 1968 that allowed non-telephone company equipment to be connected to the public telephone network. CAS Computerized autodial system. CASE 1. Computer-Aided Software Engineering; the hardware and software technologies that support the efficient implementation of disciplined software engineering methodologies and procedures. 2. Common Applications Service Element; provides general application, synchronization, and communications services. CAT 1. Computer-Aided Testing. 2. Computerized Axial Tomography. catanet A collection of networks that are interconnected via gateways. cathode-ray tube (CRT) An electronic vacuum tube that displays text or graphic images. CATV See community antenna television. CAU 1. Command/Arithmetic Unit. 2. Controller AdapterUnit. 3. CPU Access Unit. CBA Computer-Based Automation. CBDS Connectionless broadband data service. CBEMA Computer and Business Equipment Manufacturers Association; an organization of vendors that have announced TOP plans and/or products. CBX 1. Computerized branch exchange. 2. centralized branch exchange. See private branch exchange. CCD See charge-coupled device. CCIS See common channel interoffice signaling. CCITT (Consultative Committee for International Telegraph and Telephone An agency of the International Telecommunications Union whose purpose is to promote compatibility between the communications practices and performance standards of various nations. CCITT (International Telegraph and Telephone Consultative Committee) See International Telecommunications Union-Telecommunication standardization sector. CCITT Group I CCITT standard for analog facsimile devices that transmit or receive a page in 4 to 6 minutes. CCITT Group II CCITT standard for analog devices that typically operate at 3-minute speeds and offer some degree of data compression. CCITT Group III CCITT standard for digital facsimile devices operating at speeds of one minute or less. CCITT Group IV CCITT standard for digital devices with operating speeds of five seconds or less. These units interface with public data networks through packet-switching nodes. CCL Communications Control Language. CCP 1. Channel Control Processor. 2. Communications ControlPackage. 3. Communications Control Program (Unisys). CCR 1. Channel Command Register. 2. Commitment, Concurrency, and Recovery. CCS 1. Common Communications Support; initial support was provided within CCS for SNA protocols, including LU2 and LU6.2. Subsequently, the CCS interface was extended to support a variety of TCP/IP and OSI protocols. 2. Hundred Call Seconds; a measurement of telephone traffic load calculated by multiplying the number of calls per hour by the average call duration in seconds and dividing the result by one hundred (e.g., 10 CCS = 1000 seconds). CCSA See common control switching arrangement. CCSA access A PBX feature that allows a user to gain entry to a CCSA network. CCSR See centrex customer station rearrangement. CCTV See closed circuit television. CD Compact Disc. A standard medium for storage of digital audio data, accessible with a laser-based reader. CD-I Compact Disc Interactive. A compact disc format, developed by Philips and Sony, which provides audio, digital data, still graphics and limited motion video. CD-R Recordable CD disc. CD-RDx Compact Disc Read-only Data eXchange. A proposed standard for full-text retrieval from CD-ROMs. CD-ROM Compact Disk/Read-Only Memory. CD-ROM XA Compact Disc Read Only Memory eXtended Architecture. Microsoft's extensions to CD-ROM that interleaves ADPCM-digitized audio with data. CD-V A compact disc format that combines full-motion video with digital audio. CDA Compound Document Architecture; a file format for documents, consisting of text, graphics, and images (Digital Equipment). CDA/DDIF Compound Document Architecture/Digital Document Interchange Format (Digital Equipment). CDC See call directing code. CDDI See copper fiber distributed data interface. CDMA See code division multiple access. CDPD See cellular digital packet data. CDR See call detail recording and station message detail recording. CDTV Commodore Dynamic Total Vision. Consumer multimedia system which includes a CD-ROM/CD player, 68000 processor, 1 meg of RAM and a remote control. cel Short for celluloid. In computer-based animation programs, a cel is an image clipped from all or part of a frame. cell The geographic region in which all cellular transmissions are controlled by a single cell site. cell relay Technology based on small, fixed-size electronic packets or cells; because the cells are fixed they can be processed and switched at very high speeds; it is the basis of many high- speed technologies, such as SMDS and ATM. cell site The structure that contains the radio and control equipment needed to connect cellular telephone transmissions to the mobile telephone switching office (MTSO). Cell sites can be free- standing structures or located on existing buildings and towers. cellular digital packet data (CDPD) A service that allows users to send data over existing analog cellular networks. Data is sent in packets during idle time on the cellular analog channels. cellular geographic service area The geographic area served by a cellular system within which the licensee is required to provide reliable service. cellular telephone A mobile radio system that consists of hexagonal geographic areas with groups of frequencies allocated to each cell. Seven cells comprise a block, and no adjacent cell uses the same set of frequencies; however the frequency allocation pattern is the same in each successive block. Also called cellular radio. CELP Code excited linear prediction, an analog-to-digital voice coding scheme. CEN European Standards Institute (Comite Europeen de Normalisation). CENLEC European Electrical Standards Institute (Comite Europeen de Normilisation Electrique). central office (CO) Telephone company's main switchiing location that provides local access to the public network. central office equipment (COE) Apparatus used in the centraloffice of a telecommunications service. central office PBX trunk The facility between the telephone company central office and the interface at the user PBX. central processing unit (CPU) Control unit within a computer that manages the intelligent functions of the systems. In a telephone switch, it directs all portions of the system to carry out their appropriate functions. See also common control. centralized attendant service (CAS) The ability of attendants at one location to answer and service calls for other telephone systems within the same geographic area. centralized automatic message accounting (CAMA) Toll calls are recorded at a centralized point. centralized processing A networking environment in which a host computer system controls data processing, information distribution, and file transfer. Centrex A telephone company service providing direct-inward and outward dialing for PBX extensions. Centrex CU The telephone company provides a switch located at the customer's premises. Centrex customer station rearrangement (CCSR) A feature that requires the use of CPE and allows the Centrex users to make their own moves and changes. Centronics A standard 8-bit, 36-pin parallel interface for connecting printers and other devices to a computer. CEPS Color Electronic Prepress System. A computer-controlled imaging and pagination system for color printing. If the color computer is digital, it uses the Neugebauer equations to calculate color values. CEPT See Conference of European Posts and Telecommunications. CFT Cray FORTRAN (Cray Research). CGA Color Graphics Adapter. CGI Computer Graphics Interface. CGM Computer Graphics Metafile; an ANSI and ISO file format specification that is machine-independent and can store multiple pictures in a single file that can be randomly accessed. channel A path or circuit along which information flows. A simplex channel carries information in one direction. A half-duplex channel carries information in either direction alternately, but not simultaneously. A duplex or full-duplex channel carries information in both directions at the same time. channel bank A device that multiplexes many slow speed voice or data conversations onto a high speed link and controls the flow of these conversations. channel capacity A measure, subject to constraints, of the maximum amount of data that a channel can manage. channel service unit A device that performs line conditioning (e.g., equalization and signal reshaping) and incorporates line loopback test capability. channel, grade The relative bandwidth of a channel: narrowband, voicegrade, or wideband. channel, voicegrade A channel suitable for transmission of speech, digital or analog data, or facsimile, generally with a frequency range of about 300 to 3000 Hz. character generator Functional units that convert the character code into the shape of the character for display. character parity The process of adding a redundant overhead bit to a character to provide error detection capability. character-oriented protocol See byte-oriented protocol. charge-coupled device (CCD) An electronic device that transforms an image focused on its sensor into discrete electrical signals to produce a TV picture. check, block redundancy See block redundancy check. check, cyclic redundancy See cyclic redundancy check. check, longitudinal redundancy See longitudinal redundancy check. checkpoint A marker inserted into a file to support error recovery and restart functions. CICS See customer information control system. CIR See committed information rate. circuit 1. A communications path between two points. 2. The physical medium on which signals are carried across the AUI. See also channel. circuit board A board upon which microprocessors, transistors and other components are mounted. circuit grade The data-carrying ability of a circuit measured in speed or type of signal, such as broadband, voicegrade, subvoice, and telegraph. circuit switched data A method for keeping the circuit open between users for the duration of the connection. circuit switching A communications switching system that completes a circuit from sender to receiver at the time the call for message transmission is initiated. Used when there is a requirement for instantaneous, direct two-way communications between terminal locations without the time delay of message relaying. circuit, central office trunk A trunk circuit located at the PBX end of a PBX trunk. circuit, dialed A manual or automatic connection established through the switched telephone or message netwwork by dialing or keying a tone transmitter. circuit, duplex A circuit that accepts independent communications in both directions simultaneously. circuit, four-wire A circuit using two one-way transmission paths that can be two carrier paths or two pairs (four wires) of metallic conductors. circuit, half-duplex A circuit with single loops to terminals capable of two-way nonsimultaneous operation. circuit, message A circuit used for completing telephone calls. circuit, multipoint A circuit connecting three or more points. circuit, private line A leased communications path, local or toll, assigned for the private use of one customer and having no connection to the public telephone system. circuit, simplex A circuit using ground return and permitting communications in either direction -- one direction at a time. circuit, trunk See trunk curcuit. circuit, two-wire A metallic circuit formed by two conductors insulated from each other. circuit-switched cellular Two-way wireless data connectivity on cellular telephone systems. CISC Complex Instruction Set Computer. CIU Computer Interface Unit. CIW CPI-C Implementers' Workshop. cladding In fiber optics, one form of fiber (calling cladding) surrounds a center core. class of office A rank assigned to switching offices, according to its functions, its relationships to other switching offices, and transmission requirements, in the telephone network. All called class of exchange. class of service A numerical index that is assigned to each extension and determines trunk access and features available to the user. In an intercept operation, the station is automatically routed to the attendant if it attempts to place a call that is not authorized by its class of service. clear channel capability (CCC) 1. The bandwidth of a data transmission path available to end users after control and signaling bits are accounted for. 2. A 64K bps channel in which all 64K bps is available for data. clear-forward/clear-back signal Signal sent in a forward or backward direction to announce that the called party has cleared. clear-to-send The signal transmitted to a sending modem to start the data transmission process. client 1. A software module that makes a request for services. 2. A computer, such as a PC, that acts as a client in aclient/server network system. client-server environment A network in which one or more PCs act as servers, while other nodes on the network act as clients, requesting files or applications from the server. client/server architecture An architecture that consists of a client module that makes requests from a server module, which fulfills these requests. In popular client/server systems, the client module often resides on a PC or workstation and is connected to a server via networking. client/server computing Distributed network computing where applications are executed cooperatively by two computers: the client workstation, where processing is done; and the server, which holds and metes out files, databases, etc., as needed. client/server platform The hardware/software combination where a client/server system resides. The term can also refer to software alone or hardware alone. CLIO Conversational Language for Input/Output. clipper A complex data encryption program. clipping First words during a telephone conversation (usually on an overseas channel) are broken off orclipped, because the line is being shared by many conversations. CLNP Connectionless Network Protocol (OSI). clock A repetitive signal used to control a synchronous process such as logic or transmission. clocking Regularly timed signals which control synchronous transmissions. closed architecture A software or hardware system whose technical specifications are not made public by the vendor. closed circuit television (CCTV) Nonbroadcast TV system, typically used for in-house purposes (e.g., security monitoring, teaching). closed user groups (CUG) A subgroup of network users that is treated as an entity, whereby any member of the subgroup can communicate only with members of that subgroup. CLTS Connectionless Transport Service. CLU Central Logic Unit. cluster A group of terminals connected at a single point and managed by a terminal control unit called a cluster controller. CLV Constant Linear Velocity. A disk technique that spins a disk at different speeds. CMIP Common Management Interface Protocol; a protocol developed by IBM and 3Com and endorsed by the ISO that provides a specification and the formats for collecting network management data. CMIP is an alternative to SNMP. CMOS See complementary metal oxide semiconductor. CMS 1. Communication Management System (Unisys). 2. Computer Management System (Unisys). 3. Conversational Monitor System (IBM). CNET Communications network. CNLP Connectionless Network Layer Protocol. coaxial cable A connecting cable that comprises an insulated wire, which runs through the middle of the cable, and another wire, made up of solid or mesh metal, that covers the insulated wire. See also twisted-pair and fiber-optic cable. COBOL COmmon Business Oriented Language. A high-level programming language adopted in 1960 for use on minicomputers and mainframes in business environments. CODASYL Conference on Data Systems Languages; a volunteer organization of computer professionals, formed in 1959 in an attempt to standardize a computer programming language. code 1. A set of rules specifying the way in which data can be represented (e.g., the set of specifications in the ASCII). 2. In data communications, a system of rules and conventions, in which signals -- representing data -- can be formed, transmitted, received, and processed. 3. In data processing, representation of data or computer program information in a symbolic form that can be accepted by a data processor. code calling Specific numbers are assigned for routing or other purposes. code character The representation of a discrete element or elements in accordance with a code. code conversion Process of changing the bit representation for a character in one code into a corresponding bit representation for the character in another code. code division multiple access (CDMA) A form of digital cellular communication that assigns a unique numerical code to each cellular conversation, allowing numerous calls to be transmitted simultaneously on one radio frequency. code ringing Calling on a multi-party line using a combination of long and short rings. code, area See code, numbering plan. code, ASCII A standard 8-bit-per-character data transmission code that achieves compatibility among data devices. code, Baudot A 7.42-unit data transmission code in which five bits of equal length represent one character preceded by a one-unit start bit and followed by a 1.42-unit stop bit. code, binary coded decimal (BCD) A compression scheme in which two binary bits replace the three zone bits and four binary bits replace the nine data bits. code, EBCDIC (Extended Binary-Coded Decimal Interc An 8-bit-per-character code used to identify and exchange various types of data. code, numbering plan area (NPA) A 1-, 2-, or 3-digit code that, for distance dialing, designates one of the geographic areas within a country (and some neighboring territories) covered by a separate numbering plan. CODEC See coder/decoder. coder A converter that changes analog voice signals to digital equivalents. coder/decoder (CODEC) A device that transforms such analog signals as speech and video into bit streams for digital transmission and performs the reverse at the receiving end. COE See central office equipment. coin-value tones When different coins are deposited in a pay telephone, tones are produced that detect the value of the coin and transmit this information to the operator who checks to see if the amount is correct for completing the call. COLD Computer Output to LaserDisc. Replacing paper output with optical media. collect call Also called reverse charge call. collision The simultaneous transmission of data by two or more network nodes. collision avoidance (CA) See carrier sense multiple access (CSMA). collision detection (/CD) See carrier sense multiple access (CSMA). collocation The ability of an alternative access vendor (AAV) to connect its network to the local telephone company's central offices. The local telephone company permits the AAV to connect to its network at competitive prices. color graphics adapter (CGA) Provides 200V x 600H resolution with digital video signals. COM Computer Output Microfilm. The process of converting data (having been input by a number of means) to microfilm or microfiche. COMAL Common Algorithmic Language. comb In forms creation, a horizontal line with short vertical strokes in which hand-printed entries are to be made. Constrains handprinting for easier character recognition. Comite Consultatif International de Telephonie et International Consultative Committee for Telephone and Telegraph. commitment A point in time, during file access or transfer, when actions are made permanent. Mixed-protocol networks. committed information rate (CIR) The guaranteed theshold that will be maintained by the frame relay service provider when data is being sent over the carrier's network. common business oriented language See COBOL. common carrier A government regulated private company that provides the general public with telecommunications services and facilities. common channel signaling system number 7 A newer, out-of-band signaling system that is replacing CCIS. This protocol uses destination routing, octet oriented fields, variable length messages, and a maximum message length allowing for 256 bytes of data, in addition to flow control, connectionless services and ISDN. common control See central processing unit (CPU). common control redundancy A feature that allows configuration of a redundant common control unit; in the event of the main control failure, the redundant unit automatically switches on. common intermediate format (CIF) Describes the type of coded video frame transmitted when using ITU-TSS Rec. common management information protocol/services (C Standards defined by the OSI for managing mixed- computer, mixed-protocol networks. common-battery signaling The most common method of signaling, in which the signaling power of a telephone is supplied by the battery that drives the central equipment. common-channel interoffice signaling (CCIS) Digital technology used by AT&T to enhance ISDN; uses a separate data line to route interoffice signals to provide a faster call set-up and more efficient use of trunks. common-control switching arrangement (CCSA) A private switched network. communication The transmission or reception of information, signals or messages. communication line Any channel, such as a cable or circuit, that links remote stations for purposes of transmitting or receiving data. communications channel See channel. communications control character A character used to control transmission over data networks. ASCII specifies 10 control characters that are used in byte-oriented protocols. communications controller A control unit whose operations are managed by one or more programs stored and executed in the unit. communications processor The primary function of a communications processor is to establish a communications link between a host computer and external communications devices. This includes communications with other computers, between computers and data terminal equipment, between computers and data switching devices, and between computers and LANs. communications satellite An orbiting vehicle that relays signals between communications stations. There are two types: active, which receives, regenerates, and retransmits signals between stations; and passive, which reflects communications signals between stations. communications satellite Corporation (COMSAT) A U.S. company created by an act of Congress in 1962 to provide communications via satellites. COMSAT leases satellite circuits to many U.S. companies and is active in international communications through partial ownership in the International Telecommunications Satellite Organization (INTELSAT) and the International Maritime Satellite Organization (INMARSAT). communications, data The movement of encoded information from one point to another by means of an electrical transmission system. community antenna television (CATV) A term usually applied to urban cable television stations or distributors. compact disc See CD. compandor An electronic device that expands the incoming speech volume and compresses the outgoing speech volume range on a long distance telephone circuit. compatibility 1. In computers -- compatibility exists when two computers produce comparable results when running identical programs. 2. In equipment -- peripherals and components are interchangeable with one another. 3. In communications -- signals can be exchanged without the addition of buffering, translative, or similar devices. competitive access providers (CAPs) A company that provides its customers with an alternative to the local telephone company for local transport of private line and special access telecommunications services. complementary metal oxide semiconductor A technology for making integrated circuits known for requiring less electricity. component video signal A video signal in which the green (G), red (R), and blue (B) picture components are present as individual signals. composite video signal A video signal incorporating luminance color and synchronizing information. compound device An MCI multimedia device that requires media files to operate. compressed audio routing A digital process that reduces the bits necessary to encode and transmit information. Compressed SLIP A variation on SLIP in which the IP header information is compressed. compression Reduces the bandwidth or bits necessary to encode information in order to conserve storage space and/or transmission time. compressor An electronic device that compresses the volume range of a signal. See compandor. COMPROC Command processor (software). computer network A complex consisting of two or more inter-connected computer units. Computer supported telephony application (CSTA) The European Computer Manufacturers Associations standard for linking computers to telephone systems. Computer Telephone Integration (CTI) A term for connecting a computer to a telephone switch and having the computer issue the commands to move calls around. Computer-to-PBX interface See CPI. computerized branch exchange (CBX) See private branch exchange. COMSAT See Communications Satellite Corporation. concatenation The connection of transmission channels as in a chain. concentrator A device -- usually based on TDM technology -- used in data communications to multiplex numerous low-speed communications lines. The concentrator, like the front-end processor, queues inputs, frames data for transmission, establishes the communications link and multiplexes the data onto the communications line. As a receiver, the concentrator demultiplexes the data stream, checks for errors in accordance with the communications protocol, and distributes data to the terminal addressed in the message stream. conditioning 1. Minimizes detrimental circuit characteristics such as attenuation, impedance, propagation delay, and phase distortion by adding and fine tuning equipment. 2. The degree of quality provided on a leased line according to a tariff schedule. conducting materials Substances that offer relatively little resistance to the passage of an electric current. conductor 1. Any equipment, such as a wire or cable, that can carry an electric current. 2. One wire of a pair of wires. conduit Pipe or tubing through which cables are run. conference bridge A network used for interconnecting three or more lines or trunks to provide simultaneous conversation. conference call 1. A call in which more than two parties can speak. 2. PBX feature enabling the attendant to add inside and outside parties to a call until a preset system limit (usually eight to ten parties) is reached. Conference of European Posts and Telecommunication A European organization that discusses operational and tariff concerns. confidence A measurement of how certain an OCR is that it has correctly identified the character. configuration The arrangement of computers and peripheral devices on a network. connect signal An off-hook signal transmitted forward which indicates a trunk seizure. connect time 1. A measure of system use, usually the time during which the user terminal was on-line during a session. 2. The amount of time it takes a switching system to connect the calling and called parties. connecting arrangement The manner in which the facilities of a common carrier and the customer are interconnected. connectorized Circuits finished so that no additional wiring, soldering, or connection is needed for installation and operation. consecutive dialing -- attendant Dial keypad of the attendant console continues to generate DTMF signals while the console is engaged in a station and trunk connection. conservative recognition An OCR that uses rules and parameters that increases the chance of a correct identification. Results in a higher reject rate, but fewer mistakes. See aggressive recognition. console In telecommunications, a small, manually-operated attendant's unit mounted on a desk or table. constrained handprinting The ability of an OCR to recognized handprinted characters when the writer is restricted to certain rules. consultation hold PBX feature that permits an extension to place a call on hold while speaking with another call. Also called broker call. consultation hold all calls Same as consultation hold, but not restricted to incoming calls. content addressable memory (CAM) A memory device that stores and retrieves data based on a key value as opposed to an address or name. contention The condition that arises when two network nodes compete for the same transmission channel simultaneously. continuity Matching all elements between shots in a video. continuity check A performance test which determines that a transmission path is uninterrupted. continuous presence A video processing transmission and display mode that involves combining parts of two separate video images for transmission in a single data stream followed by display on a single device. continuous tone An image that has all the values (0 to 100 percent) of gray (black & white) or color in it. A photograph is a continuous tone image. Contrast with halftone. continuously variable slope delta modulation (CVSD A type of delta modulation in which the size of the steps of the approximated signal are progressively increased or decreased as required to make the approximal signal closely match the input analog wave. contone Slang for continuous tone. contrast The degree of difference between the lightest and darkest tones in an image. control character A character whose occurrence in a given context initiates, modifies, or stops a control operation. control procedure See protocol. control signals One of several lines or leads on a communications interface whose purpose is to convey status rather than data. control station The station on a network that supervises control procedures, including polling, calling, and error recovery. See also primary station. control track 1. A track on an optical disc that contains the formatting information necessary for writing, reading, and erasing the data tracks. 2. The timing pulses recorded on videotape to maintain a constant playback. control unit (CU) 1. Central processor of a telephone switching device. 2. A device that concentrates data from several terminals onto a single communications line. Also called cluster controller. control, wired-program A means of system control using wired logic (hardware). controlled station-to-station restriction Allows the attendant to inhibit station-to-station calling. When activated, attempted station calls are interrupted by the attendant. convergence The intersection of red, green, and blue electron beams on one CRT pixel. conversational mode A sequence of alternating entries and responses between a user and the system, similar to a dialogue between two persons. conversion The translation or change from one data communications method to another. converter, dime A device that receives dual-tone multifrequency (DTMF) address signals and converts them to dial pulses. cooperative processing Allows two computer systems to share the same workload. See distributed processing. copper fiber distributed data interface (CDDI) A version of fiber distributed data interface (FDDI) that runs on unshielded twisted-pair cabling rather than optical fiber. CORBA Common ORB Architecture. See ORB. COS 1.Corporation for Open Systems. 2.See class of service. cost component Price of each type of long distance service and/or equipment that constitutes a configuration. country code The combination of one, two, or three digits identifying the particular country. coupler A multiport device used to distribute optical power. CP/M Control Program/Microcomputer; Digital Research's family of operating systems. CPCI Common Programming Interface for Communications (IBM). CPE See customer-premise equipment. cpi Characters per inch. CPI 1. Common Programming Interface; an interface that consists of hundreds of verbs that control the programmer's access to source languages, data base services, communication services, repository services, and common utilities. To ensure the portability of applications within IBM's SAA environments, programmers must use the SAACPI services, not the services provided by a proprietary application development tool, such as a 4GL or a CASE product 2. Computer-to-PBX interface. CPI-C Common Programming Interface for Communications. CPID See calling party identification. CPL Conversational Programming Language (Digital Equipment). CPO Concurrent Peripheral Operations. cps 1. Characters Per Second. 2. Cycles Per Second. 3. Cards Per Second. CPU See central processing unit. crash Breakdown caused by a hardware or software malfunction. CRC See cyclic redundancy check. critical path scheduling A project management system in which all activities that culminate in completing a project are drawn on a network diagram showing the sequential order of the steps. cross modulation Interference when a carrier signal becomes modulated by an interfering and unwanted signal as well as the wanted signal. cross-connection Easy-to-change or remove wire that is loosely run between equipment terminals to establish electrical paths. crossbar switch A switch having a plurality of vertical and horizontal paths, and an electromagnetically-operated mechanical means for interconnecting any one of the vertical paths with any of the horizontal paths. crosspoint A set of contacts that operate together to improve the speech and signal channels in a switching network. crosstalk The unwanted transfer of energy from one circuit (the disturbing circuit) to another circuit (the disturbed circuit). crosstalk attenuation The extent to which a communications system resists crosstalk. CRP Capacity Requirements Planning. CRS Communications resource system. CRT See cathode-ray tube. CSLIP See Compressed SLIP. CSMA See carrier sense multiple access. CSMA/CD See carrier sense multiple access with collision detection. CSR See Customer Service Record. CSTA See Computer Supported Telephony Application. CSU See channel service unit. CT2 (Cordless Telephone 2) Second generation (digital) cordless telephones for personal communications networks (PCN). CTA See circuit terminating arrangements. CTI See Computer Telephone Integration. CTOS 1. Cartridge Tape Operating System (Datapoint). 2. Convergent Technologies Operating System. CTS Communications Terminal Synchronous. CUA Common User Access; component of IBM's SAA; an interface thatspecifies the functionality of user interaction with all applicationsthat are compliant with IBM's SAA environment. CUG See closed user groups. current loop (20mA) A common communications circuit connecting two devices in which the amount of current flowing in the conductor equals 20 milliamperes. custom keyset A multibutton telephone designed for a particular PBX. customer access line charges (CALC) Fee paid by a customer to gain entry to a telephone company system (Centrex). customer information control systems (CICS) IBM software facility that enables transactions at remote terminals to be processed centrally. customer service record (CSR) Detailed listing of a subscriber's equipment and service charges. customer-premise equipment (CPE) Equipment and facilities on the customer side of the point of interconnection with the telecommunications network. cut through Establishment of a complete path for signaling and/or audio communications. cutover The replacement of an existing phone system with a new operational facility. CVSD See continuously variable slope delta modulation. CXR See carrier. CYBER Computer series (Control Data). cyclic redundancy check (CRC) An error detection method in which the block check character is the remainder after dividing all the serialized bits in a transmission block by a predetermined binary number -- or a polynomial based on transmitted data. cycolor A printing process that allows full color, full tonal reproductions of continuous tone images. Uses a special film that is embedded with microcapsules containing dyes.