chat scriptA batch of commands and responses, prerecorded on a terminal computer, for the purpose of facilitating easy or automatic access to a network.
CheckA written order instructing a financial institution to pay immediately on demand a specified amount of money from the check writer's account to the person…
check bitA bit, such as a parity bit, derived from and appended to a bit string for later use in error detection and possibly error correction. 2.
check characterA character, derived from and appended to a data item, for later use in error detection and possibly error correction.
Check DigitOne digit, usually the last, of an identifying field is a mathematical function of all of the other digits in the field.
check loopA device that is attached to interconnect the Go and Return paths of a circuit at the incoming end of a circuit on command to permit maintenance personnel…
check sequence (CS)A 16-bit sequence in the last two octets of a frame (excluding flags) that offers a cyclic redundancy check (CRC).
check wordCipher text generated by cryptographic logic to detect failures in cryptography. [INFOSEC-99]
checkboxAn element in a Web page's interactive form that allows users to select an option associated with that element.
checking codeMachine instructions used in the detection or interpretation of certain data or data fields from a diskette, for the purpose of determining whether the…
checksumA computed value that depends on the contents of a file. It is stored with data to detect file corruption.
checkvalueIn cryptography, a computed value that results from passing a data value through an irreversible algorithm. [After X9.24]
chip rateThe rate of encoding. [NTIA] 2. In direct-sequence-modulation spread-spectrum systems, the rate at which the information signal bits are transmitted as a…
chip timeIn spread-spectrum systems, the duration of a chip produced by a frequency-hopping signal generator.
chirpingThe rapid changing, as opposed to long-term drifting, of the frequency of an electromagnetic wave.
chosen-plaintext attackIn cryptography, an analytical attack in which a cryptanalyst can submit an unlimited number of plaintext messages and examine the corresponding…
chroma keyingIn television, nearly instantaneous switching between multiple video signals, based on the state, i.e.
chroma noiseNoise that manifests itself in a video picture as colored snow. [After Silicon]
chromatic dispersionA commonly used (but redundant) synonym for material dispersion. See dispersion.
chromaticity diagramA two-dimensional Cartesian plot that depicts the multidimensional subjective relationship among colors perceived by the normal human visual system (eyes…
chrominanceThe difference between a color and a specified reference color having a specified chromaticity and an equal luminance. [After Laurin]
chrominance signalIn color television, that signal or portion of the composite signal that bears the color information.
Chronic TrunkTrunk: A trunk experiencing a much higher then normal rate of failure or switching irregularities, over a period of time, with resulting high incidence of…
CIEAbbreviation for Commission International de l'Eclairage (International Commission on Illumination).
CipherSeries of transformations that converts plaintext to ciphertext using the Cipher Key.
Cipher SystemA cryptographic system in which cryptography is applied to plain text elements of equal length.
cipher text1. Enciphered information. [INFOSEC-99] Note: Cipher text is the result obtained from enciphering plain or encoded text. 2.
cipher text auto-keyCryptographic logic that uses previous cipher text to generate a key stream. [INFOSEC-99]
ciphertext stringIn cryptography, ciphertext that is formed by encrypting concatenated encryption elements. [After X9.23]
ciphertext substringIn cryptography, a segment of a ciphertext string. [After X9.23]
ciphonyThe process of enciphering audio information, resulting in encrypted speech. [INFOSEC-99] Note: "Ciphony" is a contraction of "ciphered telephony ."
CircuitA device, or system of devices, that allows electrical current to flow through it and allows voltage to occur across positive and negative terminals.
circuit identification codeInformation identifying a circuit between a pair of exchanges, for which signaling is being performed (14 bits in the ISDN user part). [T1.110-1987]
circuit kilometersThe route kilometers of revenue producing circuits in service, determined by measuring the length in terms of kilometers, of the actual path followed by…
circuit noise levelAt any point in a transmission system, the ratio of the circuit noise at that point to an arbitrary level chosen as a reference.
circuit reliability (CiR)The percentage of time a circuit was available for use in a specified period of scheduled availability.
circuit restorationThe process by which a communications circuit is established between two users after disruption or loss of the original circuit.
circuit routing: In open systems architecture, the logical path of a message in a communications network based on a series of gates at the physical network layer in the…
circuit switchingA method of routing traffic through a switching center, from local users or from other switching centers, whereby a connection is established between the…
circuit switching unit (CSU)Equipment used for routing messages over common-user circuits that interconnect a source data terminal equipment (DTE) to a sink DTE for information…
circuit transfer modeIn ISDN applications, a transfer mode by means of permanent allocation of channels or bandwidth between connections.
circuit-switched data transmission serviceA data transmission service requiring the establishment of a circuit-switched connection before data can be transferred from source data terminal…
circular polarizationIn electromagnetic wave propagation, polarization such that the tip of the electric field vector describes a helix.
circulatorA passive junction of three or more ports in which the ports can be accessed in such an order that when power is fed into any port it is transferred to…
civisionThe application of cryptography to television signals. 2. Television signals that have been enciphered to preserve the confidentiality of the transmitted…
claddingOf an optical fiber, one or more layers of material of lower refractive index, in intimate contact with a core material of higher refractive index. 2.
cladding diameterIn the cross section of a realizable optical fiber, ideally circular, but in practice assumed to a first approximation to be elliptical, the average of…
cladding modeAn undesired mode that is confined to the cladding of an optical fiber by virtue of the fact that the cladding has a higher refractive index than the…
cladding mode stripperIn an optical fiber, anything used to convert cladding modes to radiation modes, thus removing them from the fiber.
classArticle I, section 3 of the Constitution requires the Senate to be divided into three classes for purposes of elections.
class d addressSynonym (in Internet protocol) multicast address.
class of emissionThe set of characteristics of an emission, designated by standard symbols, e.g.
class of officeA ranking, assigned to each switching center in a communications network, determined by the center switching functions, interrelationships with other…
class of serviceA designation assigned to describe the service treatment and privileges given to a particular terminal. 2.
Classificationpatents are classified (organized) in the U.S. by a system using a 3 digit class and a 3 digit subclass to describe every similar grouping of patent art.
classmarkA designator used to describe the service feature privileges, restrictions, and circuit characteristics for lines or trunks that access a switch.
clearTo cause one or more storage locations to be in a prescribed state, usually that corresponding to a zero or that corresponding to the yyspace character.
clear channelIn radio broadcasting, a frequency assigned for the exclusive use of one entity. 2.
clear channel capability (CCC)A characteristic of a transmission path in which the bit position allocated for customer data may represent any combination of zeros and ones.
clear collisionContention that occurs when a DTE and a DCE simultaneously transfer a clear request packet and a clear indication packet specifying the same logical…
clear confirmation signalA call control signal used to acknowledge reception of the data-terminal-equipment (DTE) clear request by the data circuit-terminating equipment (DCE) or…
clear message1. A message that (a) is sent in the forward direction and the backward direction, (b) contains a circuit-released signal or circuit-released…
clear textUnencrypted, non-machine dependent, ASCII text in readable form.
ClearanceClearance is the first half of the process that completes your order to buy or sell a security.
ClearingThe registration and settlement of a trade that includes provisions for margin requirement and performance guarantee.
cleaveTo break phosphodiester bonds of double-stranded DNA, usually with a type II restriction endonuclease. Synonyms: cut; digest.
CLECAbbreviation for competitive local exchange carrier. The new local exchange carrier that is attempting to compete outside its traditional operating…
click dataData obtained by analyzing the log file containing information regarding who has accessed the Web page or the banner under consideration.
click rateOf a Web page menu item, especially an advertisement, the ratio of (a) the number of time it is selected ("clicked") to (b) the number of times it is…
Click throughThe process of clicking on a link in a search engine output page to visit an indexed site.
clientAny computer system that requests a service of another computer system. A workstation requesting the contents of a file from a file server is a client of…
client IDA unique identification number used when sending data to a specific client. Clients that are standardized for use in generic applications are allocated…
client-server architectureThe structural basis of Exchange. The client sends requests to a server, and the server carries out the instructions. [Exchange 5.5]
Client/ServerAn architecture whereby a computer system consists of one or more server computers and numerous client computers (workstations).
cliff effectIn the digital transmission of analog signals, including analog television and digital audio broadcasting (DAB), a signal-quality effect in which the…
clipThe spatial extraction of those features from one coverage that reside entirely within a boundary defined by features in another coverage (called the clip…
clipper1. A circuit or device that limits the instantaneous output signal amplitude to a predetermined maximum value, regardless of the amplitude of the input…
clippingIn telephony, the loss of the initial or final parts of a word, words, or syllable, usually caused by the nonideal operation of voice-actuated devices. 2.
CLLI™A CLLI⢠Location Identification Code is an eleven-character alphanumeric descriptor used to identify switches, points of interconnection, and…
clockA reference source of timing information. 2. A device providing signals used in a transmission system to control the timing of certain functions such as…
clock accuracyThe level of agreement of the frequency of a clock with the ideal frequency. This is specified as the magnitude of the fractional frequency offset from…
clock errorThe difference between local clock time or value and a designated reference clock time or value.
clock fast modeAn operating condition of a clock in which it is locked to an external reference and is using time constants that are altered to quickly bring the local…
clock free-run modeAn operating condition of a clock in which its local oscillator is not locked to an external synchronization reference, and is using no storage techniques…
clock holdover modeAn operating condition of a clock that has lost its controlling input and is using stored data, acquired while in normal operation, to control its output.
clock normal modeAn operating condition of a clock in which the output signals are controlled by an external input reference. It is the expected mode.
clock phase slewThe rate of relative phase change between a given clock signal and a stable reference signal.
clock rateThe rate at which a clock issues timing pulses. Note: Clock rates are usually expressed in pulses per second, such as 4.96 Mp/s (megapulses per second).