Glossary: Mostlyabreviations and acronyms:
Ask the Deacon                                        


C4 Project: Standards project conducted by 'EDS'at GM.

Cable Modem: A "Cable Modem" is a devicethat allows high-speed access to the Internet via a cable TV (CATV)network. A cable modem will typically have two connections, one to thecable wall outlet and the other to a computer (PC).

CAD: Computer Aided Design / Drafting

CAE: Computer Aided Engineering

CAM: Computer Aided Manufacturing

CAP: Carrierless Amplitude modulation / Phasemodulation; One of several xDSLmodulation methods. Typical existing CAP technology can support 51 Mbpsdownstream and 1.6 Mbps upstream over Category 3 UTP,(DAVIC).  CAP is a design of signal modulationfor Asymmetric Digital Subscriber Line transceivers developed by Bell Labs.CAP was the
first ADSL design to be commercially deployed and,as of August 1996, was installed on more lines than any other.

CAP is a variation of Quadrature Amplitude Modulation, QAM;the modulation used by most existing modems in 1997. With CAP, the threechannels (POTS, downstream data and upstream data)are supported by splitting the frequency spectrum. Voice occupies the standard0-4 Khz frequency band, followed by the upstream channel and the high-speeddownstream channel.

CAP: Competitive Access Provider

Capacitance: The capacity of electricalenergy stroage in positive and negative charges.

CASE: Common Application Service Element

CATV: CAble TeleVision, or Community AntennaTeleVision, you know... Cable.

CAU: Cable Access Unit; generally located atthe subscriber premises. It bridges the cable and separates the telephonyfrom video signals on the downstream path and injects telephony signalinto the upstream path. The unit features standard interface connectors(RJ-11) for a conventional telephone and a coaxial connection for the cableinterface into the premise.

CAV: Constant Angular Velocity; A disk readingtechnology usually used in hard drive systems.

Cb: is the digitized version of analog colorcomponent (B-Y)

CBR: Case-Based Reasoning, (AI)

CBR: Constant Bit Rate; An ATMservice type in which the ATMnetwork guarantees to meet the transmitter's bandwidth and 'quality-of-service'(QoS) requirements.

CBS: Columbia Broadcasting System

CCC: Clear Channel Capability; An ISDNService

CCIR-601: specifies the the image format,acquisition semantic, and parts of the coding for digital "standard" televisionsignals. ("Standard" television is in the resolution of PAL,NTSC, and SECAM)

CCIR-601 gives the specification for encoding of 4:2:2signals and a tentative specification of 4:4:4 encoding. 4:2:2means, that
the color-difference signals Cr and Cbare sampled with half of the sampling frequency of the luminance signalY, that is
13.5MHz to 6.75MHz.  see also: (CCIR-601).

CCITT: Commite' Consultatif Internationalde Telegraphique et Telephonique. (International consultative committeeon telecommunications and Telegraphy). Replaced by ITU-T

CCSDS: Consultative Committee for Space DataSystems

CCU: Cable Control Unit; communicates withthe cable access units, (CAU) and acts as a protocolconverter from the cable plant to an end office exchange. It allows thecable operator to integrate telephony and enhanced data services with theexisting cable TV signals.

CD: Committee Draft, (ISO/IEC)

CD: Compact Disk; A 4.75-inch (12cm) opticaldisc that contains information (usually musical) encoded digitally in theconstant linear velocity (CLV) format. This popularformat for high-fidelity music offers 90 dB signal/noise ratio, 74 minutesof digital sound, and no degradation of quality from playback. The standardsfor this format (developed by NV Philips and Sony Corporation) are knownas the Red Book. (see also CD-ROM)

CDC: Control Data Corporation

CDF: Channel Definition Format, (Microsoft)

CD-i: Compact Disc-Interactive; A compactdisk format released in October 1991 that provides audio, digital data,still graphics, and motion video. The standards for this format (developedby NV Philips and Sony Corporation) are known as the Green Book.

CDM: Code Division Multiplexing

CDMA: Code Division Multiple Access (WirelessCommunications); CDMA is often used in reference to spreadspectrum systems and refers to the possibility of transmitting severalsuch signals in the same portion of spectrum by using pseudorandom codesfor each one. This can be achieved by either frequency hopping ( A seriesof pulses of carrier at different frequencies, in a predetermined pattern)or direct sequence ( A pseudorandom modulating binary waveform whose symbolrate is a large multiple of the bit rate of the original bit stream) spreadspectrum and provides an alternative to frequency division multiple-access(FDMA) or time-division multiple access (TDMA)methods

CD-ROM: A 4.75-inch laser-encoded opticalmemory storage medium with the same constant linear velocity (CLV)spiral format as audio CDs and some videodiscs, CD-ROMscan hold about 550 megabytes of data. CD- ROMs require more error-correctioninformation than the standard prerecorded compact audio disc.

The standards for this format (developed by NV Philips and Sony Corporation)are known as the Yellow Book. See also CD-ROM XA.

CD-ROM XA: Compact Disc-Read-Only MemoryExtended Architecture; An extension of the CD-ROMstandard billed as a hybrid of CD-ROM and CD-i; and promoted by Sony and Microsoft. The extension adds ADPCMaudio from CD-i and permits interleaving of sound andvideo data for animation and sound synchronization.

CD-RW: CD ReWritable;650 MB capcity, should be readable by DVD-ROM drives based on the MultiReadformat.

CDTV: Conventional Definition Television;This term is used to signify the analog NTSC televisionsystem as defined in ITU-R Recommendation 470. Seealso standard definition television and ITU-R Recommendation1125.

CDV: Cell Delay Variation, (ATM)

CDV: Compressed Digital Video

CEI: Computer Ethics Institute (

CEMA: Consumer Electroics Manufacturers Association

CERFnet: California Education and ResearchFederation network. Could also refer to Dr. Vinton G. Cerf, co-author ofthe original paper on TCP/IP for the ARPANET.

CERL: Computer-based Education Research Laboratory

CERT: Computer Emergency Response Team; Asystem established out of Carnegie Mellon University, (CMU)in order to identify security issues with both operating systems and otherInternet based services.

CFD: Computational Fluid Dynamics

CFI: CAD Framework Initiative;setup to establish agreements, on how CAD applications may interoperate.

CFR: Constant Frame Rate; one of 'Frame Relay's'answers to QoS.

CGI: Common Gateway Interface; A set of rulesthat describe how a Web Server communicates with another piece of softwareon the same machine, and how the other piece of software (the 'CGI program')talks to the web server. Any piece of software can be a CGI program ifit handles input and output according to the CGI standard.

CGM: Computer Graphics Metafile, has threedistinct classes; /c: Clear, /b: Binary, /t: Text.

channel: A digital medium that stores ortransports a digital stream of information.

Channel capacity: The maximumtransmission throughput of a channel with a correctable number of transmissionerrors.

Channel intersymbolinterference: Interference between adjacent data symbols caused bychannel frequency and phase distortion.

Chrominance: Portion of a video signalthat carries color information (hue and saturation, but not brightness).A matrix, block, or single pel represents one of the two color-differencesignals related to the primary colors as defined in the bitstream. Thesymbols used for the color difference signals are Crand Cb. See also YCbCr.

CIAC: Computer Incident Advisory Capability;A group established by the 'Department of Energy', to debunk net pranks.

CIDR: Classless InterDomain Routing

CIEM: Computer Integrated Engineering &Manufacturing (Lockeed)

CIF: Caltech Intermediate Form; Geometry languagefor VLSI design, in which the primitives are coloredrectangles

CIF: Common Image Format; The standardizationof the structure of the samples that represent the picture informationof a single frame in digital HDTV, independent of framerate and sync/blank structure. The uncompressed bit rate for transmittingCIF at 29.97 frames/sec is 36.45 Mbps.

CIM: Computer Integrated Manufacturing

CIR: Committed Information Rate

CIX: Commercial Internet Exchange

CLI: Compression Labs, Inc. (San Jose, CA)

CLI: Command Line Interface

Clipping noise: Noise caused bythe clipping of signal peaks by DAC or ADC.

CLNP: Connectionless Network Protocol

CLTP: Connectionless Transport Protocol

CLV: Constant Linear Velocity

CM: Cable Modem

CMCI: Cable Modem-to-Customer-premises-equipmentInterface

CMIP: Common Management Information Protocol,(ISO)

CMIS: Common Management Information Service,(ISO)


CMOS: Complementary Metal Oxide Semiconductor;A semiconductor techonology whose element circuit is based on the complementarycombination of  p and n types of semiconductor material.


CMS: Configuration Management System, (WorkgroupTechnologies, Inc.)

CMS: Conversational Monitor System, (IBM)

CMTRI: Cable Modem Telephony Return Interface

CMTS: Cable Modem Termination System

CMTS-NSI: Cable Modem Termination System- Network Side Interface

CMU: Carneigie Mellon University

CNMS: Central Network Management Station;a "route server" management system.

CNRI: Corporation for National Research Initiatives,(; CNRI undertakes, fosters, and promotes research in the publicinterest. The activities center around strategic development of network-basedinformation technologies. CNRI is a not-for-profit organization.

CO: Central Office; telephone services mainswitching facility for terminating telephone subscriber loops. (SeeOSP: Outside Plant)

Code book: A mapping between input informationsequences and ouput code words.

coded representation: A dataelement as represented in its encoded form.

Companding: A method to compress a largeamplitude signal to increase the dynamic range of a voice encoder throughnon-uniform quantization.

Component video: The separationof chrominance (color) and luminance parts of the video signal. In componentvideo, these two signals are recorded separately, which helps maintainbetter picture quality over more generations.

Composite video: The complete visualwave form of the color video signal composed of chrominance and luminancepicture information; blanking pedestal; field, line, and color sync pulses;and field equalizing pulses. See also RGB.

Conductance: The capacity of electricalenergy storage in the strength electromagnetic fields.

constant bit rate: Operationwhere the bit rate is constant from start to finish of the compressed bitstream. (see also: CBR)

Convolution code: A coding mechanismwhose ouput codewords depend on input information sequences as well asthe state of the encoder.


CORBA: Common Object Request Broker Architecture,(OMG)

CPAN: Comprehensive Perl Archive Network

CPE: Customer Premises Equipment

cps: characters per second

cps: cycles per second

Cr: is the digitized version of the analog colorcomponent (R-Y)

CRC: Cyclic Redundancy Check; a frequentlyused error correction technique used in digital data communications.

Crosstalk: Noise caused by a signal carriedover adjacent telephone subscriber loops.

CSA: Carrier Serving Area; A design guidelinefor the constraining of the length of telephone subscriber loops to accommodatedigital telephone transmission equipment.

CSMA/CD: Carrier Sense Multiple Access/ Collision Detection

CSP: Consultants in Systems Programming; Contractshop headquartered in Troy, MI.

CSS: Cascading Style Sheets

CSTA: Computer Supported Telephony Applications

CSU: Channel Service Unit; Keeps the signal'sperformance consistent across the channel bandwidth, signal reshaping...

cut-through packet switching:Packet switching approach that streams data through a switch so that theleading edge of a packet exits the switch at the output port before thepacket finishes entering the input port. A device using cut-through packeteswitching reads, processes, and forwards packets as soon as the destinationaddress is looked up, and the outgoing port determined. Also known as on-the-flypacket switching. Compare with storeand forward packet switching.

CT: 1. Computer Telephony. 2. Computer Training

Cyclic code: An error correction code. The cyclic shift of a codeword from a particular cyclic code is also acodeword of the same cyclic code.

Last Update:12/13/03
Prototype InfoBase Technology