capacitive couplingThe transfer of energy from one circuit to another by means of the mutual capacitance between the circuits.
CapacityYour ability to make your mortgage payments on time. This depends on your income and income stability (job history and security), your assets and savings…
capture effectA phenomenon, associated with FM reception, in which only the stronger of two signals at or near the same frequency will be demodulated.
card sessionIn telephone-service security, a link between the card and a terminal starting with the answer to reset (ATR) and ending with a subsequent reset or a…
card validationThe validating process that includes, but is not limited to, ensuring that a telecommunications charge card has been assigned by the card issuer and that…
cardinal radialEight imaginary straight lines extending radially on the ground from an antenna location in the following azimuths with respect to true North: 0°, 45°…
carrierA heterozygous individual bearing a recessive mutant allele for a defective condition that is "masked" by the presence of the dominant normal allele; the…
carrier (cxr)A wave suitable for modulation by an information-bearing signal. 2. An unmodulated emission.
carrier access code (CAC)A code (dialed by the user) to select a specific service provided by the entity to which the code is assigned by the NANPA (North American Numbering Plan…
carrier facility systemA transmission facility that provides several telecommunication channels over a single bidirectional path.
carrier frequencyThe nominal frequency of a carrier wave. 2. In frequency modulation, synonym center frequency. 3.
carrier identification code (CIC)A numeric code assigned by the North American Numbering Plan (NANP) Administrator for the provisioning of selected switched services.
carrier leakThe carrier remaining after carrier suppression in a suppressed carrier transmission system.
carrier levelThe level of a carrier signal at a specified point in a communications system. Note: The carrier level is usually expressed in dB relative to a specified…
carrier noise levelThe noise level resulting from undesired variations of a carrier in the absence of any intended modulation. Synonym residual modulation.
carrier power (of a radio transmitter)The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation.
carrier selectionA code that identifies whether the caller dialed the elected or chosen carrier and whether the caller presubscribed to the elected or chosen carrier. [T1.
carrier senseIn a local area network, an ongoing activity of a data station to detect whether another station is transmitting.
carrier shiftIn the transmission of binary or teletypewriter signals, keying in which the carrier frequency is shifted in one direction for marking signals and in the…
carrier synchronizationIn a radio receiver, the generation of a reference carrier with a phase closely matching that of a received signal.
Carrier SystemA means of obtaining a number of channels over a single path by modulating each channel upon a different carrier frequency, and demodulating at the…
carrier-to-noise ratio (CNR)In radio receivers, the ratio of the level of the carrier to that of the noise in the intermediate frequency (IF) band before any nonlinear process, such…
Carson bandwidth ruleA rule defining the approximate bandwidth requirements of communications system components for a carrier signal that is frequency modulated by a…
CAS(1) Close Air Support. (2) Computer-Aided Servicing. (3) Crisis Action System. (4) Cost Accounting Standard.
cascade1. A series of reply posts to a message on a bulletin board system. 2. An offset stack of (usually) active windows displayed on a computer screen. 3.
CASEThe last card of a certain rank in the deck. Example: "The flop came J-8-3; I've got pocket jacks, he's got pocket 8's, and then the case eight falls on…
case shiftIn data equipment, the change from letters to other characters, or vice versa. 2.
CASE technologyTechnology that makes use of computer assisted software engineering (CASE) to enhance the development of systems design and development.
Cassegrain antennaAn antenna in which the feed radiator is mounted at or near the surface of a concave main reflector and is aimed at a convex secondary reflector slightly…
catastrophic degradationThe rapid reduction of the ability of a system, subsystem, component, equipment, or software to perform its intended function.
categoryA word, phrase, or number used to group documents in a view.
Category 3The ANSI/EIA/TIA-568 designation for 100-ohm unshielded twisted-pair cables and associated connecting hardware whose characteristics are specified for…
Category 4The ANSI/EIA/TIA-568 designation for 100-ohm unshielded twisted-pair cables and associated connecting hardware whose characteristics are specified for…
Category 5The ANSI/EIA/TIA-568 designation for 100-ohm unshielded twisted-pair cables and associated connecting hardware whose characteristics are specified for…
CAVAbbreviation for component analog video. A signal in which an analog voltage or current, rather than a set of numbers, represents the value of a pixel.
CD ROM XAAbbreviation for compact disc read only memory eXtended architecture. An extension of the CD-ROM standard, billed as a hybrid of CD ROM and CD-IS formats.
CD-iAbbreviation for compact disc-interactive. A compact disc format that provides audio, digital data, still graphics, and limited motion video, and that…
CD-ROMSee Compact Disc. (Compact Disk - Read Only Memory) Data storage medium that uses compact discs to store about 1,500 floppy discs worth of data.
CDMA (Code-division multiple access access)a digital cellular technology that uses spread-spectrum techniques. Unlike competing systems, such as GSM, that use TDMA, CDMA does not assign a specific…
CDPSKAbbreviation for coherent differential phase-shift keying.
CDRAbbreviation for complementarity-determining regions.
CEIAbbreviation for comparably efficient interconnection.
CellThe fundamental level of structural organization in complex organisms. Eukaryotic cells contain a nucleus (with chromosome s) and cytoplasm with the…
cell delay variationA quantification of variability in cell delay for an asynchronous transfer mode (ATM) layer connection. [T1.630-1999]
cell delineationThe identification of the asynchronous transfer mode (ATM) cell boundaries within a cell stream. [T1.646-1995]
cell headerAsynchronous transfer mode (ATM) layer protocol control information that precedes user data. [After T1.627-1993]
cell loss ratio1. In a network, the ratio (1- x/y), where: y is the number of cells that arrive in an interval at the ingress of the network; and x is the number of…
cell relayA statistically multiplexed interface protocol for packet switched data communications that uses fixed-length packets, i.e., cells, to transport data.
cellularRefers to communications systems, especially the Advance Mobile Phone Service (AMPS), that divide a geographic region into sections, called cells.
cellular mobileA mobile communications system that uses a combination of radio transmission and conventional telephone switching to permit telephone communication to and…
cellular technologyIn telephony, a generic term for all wireless phones, regardless of the technology they use; the term derives from cellular base stations that receive and…
center frequencyIn frequency modulation, the rest frequency, i.e., the frequency of the unmodulated carrier. Synonym carrier frequency. 2.
central office (C.O.)A common carrier switching center in which trunks and/or loops are terminated and switched.
Central Office (CO) CodeThe sub-NPA code in a TN, i.e., digits D-E-F of a 10-digit NANP Area address. Central office codes are in the form "NXX," where N is a number from 2 to 9…
central office connecting facilityLoosely, in the sense of a trunk between public and private switches, a synonym for central office trunk. See trunk.
central office prefixThe first three digits (N) of the seven-digit telephone number assigned to a customer's telephone exchange service when dialed on a local basis.
central office trunkLoosely, in the sense of a trunk between public and private switches, a synonym for central office connecting facility. See trunk.
Central Processing UnitThe Central Processing Unit (CPU) is the heart of a computer as it is the part that contains the computer's ability to obey instructions.
centralized attendant services (CAS)A function of a usually centrally located attendant console that permits the control of multiple switches, some of which may be geographically remote.
centralized automatic message accounting (CAMA)An automatic message accounting system that serves more than one switch from a central location. Note: When using CAMA, human intervention may be required.
centralized operationOperation of a communication network in which transmission may occur between the control station and any tributary station, but not between tributary…
centralized ordering group (COG)An organization provided by some communications service providers to coordinate services between the companies and vendors.
Centrex® (CTX) serviceA service offered by Bell Operating Companies that provides functions and features comparable to those provided by a PBX or a PABX. Note: "Centrex® C.O.
certificateDigital signature combining data verification and encryption key. See PKI Digital Signature.
certificate holdIn cryptography, an order suspending the use of a certificate. Note: A certificate hold is a security procedure that is analogous to placing a hold on a…
certificate informationIn cryptography, the information in a certificate which is signed. [After X9.57]
certificate management[The] process whereby certificates . . . are generated, stored, protected, transferred, loaded, used, and destroyed. [INFOSEC-99]
certificate serial numberIn cryptography, an integer value that is (a) unique within the issuing certificate authority (CA), and (b) unambiguously associated with a certificate…
certificate userIn cryptography, a station, agency, or individual user that needs to know, with certitude, the public key of another entity. [After X.509]
CertificationCertification means the approval by a certifying official that a labor condition application is complete and does not contain obvious inaccuracies.