ABBREVIATION DICTIONARY Networks and Telecommunications/Electronics --> C

C

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C Band
In electrical networks, a portion of the radio frequency spectrum. Communication satellites operate on C-band frequencies from 5.925 to 6.425 GHz for uplinks and 3.700 to 4.200 GHz for downlinks. In optical networks, a range of wavelengths between 1535nm and 1565nm.







C/N
Carrier-to-noise ratio. The ratio of carrier power to noise power in a communication channel.







CAD/CAM
Computer-Aided Design/Computer-Aided Manufacturing. A computer and its related software and terminals used to design and manufacture things. CAD terminals are often run over LANs and/or WANs.







CAP
Competitive access provider. A company that provides network links between the customer and the interexchange carrier or even directly to the Internet service provider. CAPs operate private networks independent of local exchange carriers.







CATV
Community antenna television, cable television.







CBX 500
A multiservice asynchronous transfer mode (ATM) switch that offers frame relay and Internet Protocol (IP) functionality.







CCITT
Consultative Committee on International Telegraphy and Telephony







CD
Carrier Detect







CDPD
Cellular Digital Packet Data: In cellular communications, a system that transmits packets of data over cellular networks without interfering with voice transmission.







CDR
Call Detail Reporting is a feature that provides a database of information about each call, including date, time, duration, called number, calling number, call direction, service type, and associated inverse multiplexing session and port. Because the network carrier bills for bandwidth on an as-used basis, and bills each connection in an inverse multiplexed call independently, you can use CDR to understand and manage bandwidth usage and the cost of each inverse multiplexed session.







CE certified
Signifies that a company has met the applicable health, safety and conformity requirements to market its products in the European Union.







CENELEC
Comite European de Normalisation Electrotechnique or the European Committee for standardization. Responsible for European standards in the electrotechnical field.







CGI
Common gateway interface. A standard set of rules for transferring information between a World Wide Web server and a CGI program - any program designed to accept and return data that conforms to the CGI specification. For example, a CGI program can put the content of a form into an email message, or transform data into a database query. The program can be written in any programming language, including C, Perl, Java, or Visual Basic.







CHAP
Challenge Handshake Authentication Protocol. This security protocol allows access between data communications systems prior to and during data transmission. CHAP uses challenges to verify that a user has access to a system.







CIR
Committed information rate. The minimum bandwidth guaranteed to be available if required on a virtual circuit. This value is also known as guaranteed bandwidth.







CLEC
Competitive local exchange carrier. A company that provides local dial-tone services as well as long-distance, data, and Internet services, usually to businesses.







CLID
Calling Line ID, synonymous with ANI.







CNR
Carrier-to-noise ratio. The ratio of carrier power to noise power in a communication channel.







CO
Central Office







CODEC
COder-DECoder. In the videoconferencing world, a video codec converts analog video signals from a video camera to digital signals for transmission over digital circuits, and then converts the digital signals back to analog signals for display. In the audio world, an audio codec converts analog audio signals to digital signals for transmission over digital circuits, and then converts the digital signals back to analog signals for reproduction.







CPE
Customer Premises Equipment. Terminal equipment located on the customer premises which connects to the telephone network.







CPHB
Computer Protocol Heart Beat







CPNX
Computer Protocol Network Executive







CPU
Central Processing Unit







CRC Errors
There are three standard methods of calculating the CRC: CRC-16, CRC, and CRC-12. Mention CRC errors and most will understand that there is a line or CSU problem when referencing WANs.







CSO
Composite second order distortion - in CATV systems or devices, a measure of the undesired second order distortion.







CSU
Channel Service Unit. A device used to connect a digital phone line coming in from the phone company to network access equipment located on the customer premises. A CSU may also be built into the network interface of the network access equipment.







CTB
Composite Triple Beat distortion - in CATV systems or devices, a measure of the undesired third order distortion.







CTS
Clear To Send







Cable
Wires or groups of wires carrying voice or data transmissions.







Cable Modem
In the early stages of testing, a device that promises to deliver high-speed data throughput over the coaxial cable used by the cable TV industry.







Call
A single session in which a calling device and an answering device connect over the WAN.







Call Center
A place where calls are placed or received in high volume for the purpose of communicating with customers, vendors or employees. Also, the integration of automation and telephony into a business's processes to optimize those processes and enhance service to customers.







Call Filter
A packet filter that defines which packets can bring up a connection or reset the idle timer for an established link. A call filter prevents unnecessary connections and helps the Lucent unit distinguish active traffic from "noise."







Call Filters
Call filters help you manage the cost of having a Pipeline connected to your PC or network. The Pipeline has an Idle Timer option that can be set in the Connection Profile and again in the Answer Profile. Call filters let you define which packets will not restart the Idle Timer, so only valid traffic keeps a connection up. Packets defined in a call filter cannot restart the Idle Timer or initiate a call.







Call Logging
A method for logging call information from the Lucent unit. Call logging enables you to keep records for resource management or troubleshooting. When you set up call logging, you can create duplicate accounting information for sites that wish to keep accounting records separate from records about network operations. Call logging works only with Navis Access.







Call Management System (CMS)
An application that simulates the actions of a system operator by answering and distributing calls; it also supplies management reports for call analysis.







Call Processing
The system and process that sets up a connection in a switch.







Call Request
On an X.25 network, a request made by the calling party, asking the data terminal equipment (DTE) to accept the call.







Call-log Host
A local host that supports the RADIUS Accounting Protocol and is configured to communicate with the Lucent unit.







Callback Security
Callback security is a mechanism used to verify that the access attempt is made by a recognized, legitimate caller. The caller's number is checked against a database of users.







Called Number
The called number is the intended destination of an authorization attempt.







Caller ID
Caller ID describes a service, offered by local telephone companies, that displays the calling party's number on a special display device.







Caller Identification
An ISDN telephone service that enables the called party’s equipment to display the telephone number of the call.







Capacitor
An electronic device that stores electricity. A simple capacitor consists of two conductors, separated by an insulating material called a dielectric.







Carrier
Alternating current of a fixed frequency that establishes the boundaries within which an information signal is transmitted through the air as radio waves or through a cable.







Carrier Sense Multiple Access/collision Detect (CSMA/CD)
Carrier sense multiple access/collision detect.







Carrier-to-Noise Ratio(CNR)
The ratio of carrier power to noise power in a communication channel.







Cause Codes
Codes associated with ISDN calls that provide diagnostic information like busy signals, incorrect data services, and so forth.







Cell
In asynchronous transfer mode (ATM), a 53-byte fixed length data packet; in cellular communication, a portion of a city or county. In cellular communication, each cell contains the transmitters and receivers that provide the telephone service. The frequencies assigned to one cell are limited to the boundaries of that cell. When a cellular phone moves from one cell toward another, a computer at the switch monitors the motion and hands off the phone call to the new cell, which uses another radio frequency. The transfer is not noticeable to the user.







Cell Highway
A series of circuits that enable the unit to relay packets between the cell protocol option device (CPOD) and the interface protocol option device (IPOD), expansion protocol option device (XPOD), and interface control module (ICM).







Cell Relay
A packet transmission system that uses fixed-length cells which can be processed and switched at very high speeds, making it possible to use a single transmission scheme for voice, data, and video traffic on local- and wide-area networks.







Cell Site
In cellular communications, a base station in a cellular system which supports all users within a particular cell; consists of FM radio transmitter and receiver, antenna system, computer.







Cell Switching
In a cellular network, a feature that enables a caller to move from one location to another without losing the connection. The cellular system is designed to switch calls to a new cell without a noticeable drop in the connection. While not noticeable in voice communications, the 300 milliseconds required for cell switching can cause problems in data transmission. Cell switching is sometimes referred to as handing off.







CellPipe
An ATM-over-ADSL router/bridge that uses existing single-pair copper wiring to combine data, voice, and video traffic over an ADSL line at speeds of up to 8 Mbps. The CellPipe offers telecommuters, small offices, and home offices the speed and power of ADSL-DMT technology. It accelerates applications such as Internet and intranet access, Web-based research, videoconferencing, and multimedia.







Cellular
A networking technology invented at Bell Labs that breaks up geographical areas into clusters of small honeycomb-shaped cells. The network consists of one low-powered output cell site, cellular handsets, and the MSC, which all exchange information to connect cellular subscribers.







Cellular Digital Packet Data (CDPD)
CDPD is a digital wireless transmission technique that uses idle voice channels on the existing Advanced Mobile Phone Service (AMPS) cellular telephone network. CDPD transmits data packets at a raw data rate of 19.2 Kbps, using channel hopping to move data packets through unused spaces across different frequencies.







Cellular Handset
A lightweight, portable telephone used by a subscriber to a cellular network







Cellular Network
A network that enables cellular subscribers to travel anywhere in the country and remain connected to the public switched telephone network (PSTN) by means of their mobile phones.







Cellular Telecommunications Industry Association
An organization that promotes cellular technology, addresses common cellular concerns, provides a forum for exchange of information, as well as lobbying voice in the legislature.







Central Office
The building that houses the switching equipment to which are connected circuits of business and residence phones; also called Exchange







Central Office (CO)
The building that houses the switching equipment to which are connected circuits of business and residence phones; also called Exchange.







Central Office-based Local Area Network
A collection of computers on one or several business premises interconnected through public telephone lines and acting as a single, physically-connected network. See Local Area Network.







Central Site
A location which acts as a data collection point for remote and branch offices, as well as telecommuters and travelers.







Centrex®
A centrally located, multiline business service offered by local exchange carriers that employs those carriers' central office switching and transmission facilities to permit subscribers to communicate within their organization and the world outside.







Challenge Handshake Authentication Protocol/password Authentication Protocol (CHAP/PAP)
Standard authentication protocols for PPP connections. An Internet term.







Change-filter-request Packet
A request to change the packet filters for a routing session.







Channel
A portion of a line’s bandwidth. A line contains a fixed number of channels. Each line can contain switched channels only, nailed-up channels only, or a combination of switched and nailed-up channels.







Channel Service Unit
A device used to connect a digital phone line coming in from the phone company to network access equipment located on the customer premises. A CSU may also be built into the network interface of the network access equipment.







Channel Service Units (CSU) Or Data Service Units (DSU)
Although they perform different functions, CSUs and DSUs are usually lumped together. They convert carrier line signaling to digital signals.







Channelized T1/E1
T1 or E1 service that is divided into individual 64 kbps channels (or channels that are multiples of 64 kbps such as a 256 kbps channel made from four 64 kbps channels), as opposed to unchannelized service, which uses the entire bandwidth of the T1 (1.544 Mbps) or E1 (2.048 Mbps). Channelized T1 or E1 lines can consist of switched lines with inband signaling or leased lines. Additionally, leased lines may be channelized, for example when a leased line runs from the central office to the corporate headquarters as a single T1 or E1 line, but then branches into channels to remote sites from the corporate headquarters.A line can have three types of channels:
DSO - a 64-Kbps channel on a line using inband signaling. For information on inband signaling, see the entry for Inband signaling.
B channel - 56-Kbps or 64-Kbps channel that carries user data on a line using signaling, see the entry for ISDN D-channel signaling.
D channel - carries WAN synchronization information n a line using ISDN D-channel signaling. For information on ISDN D-channel signaling, see the entry for ISDN D-channel signaling.








Chat
Real-time communication between two users on the Internet via computer.







Checksum
A count of the number of bits in a transmission unit. A checksum enables the receiving device to determine whether the same number of bits arrived as were sent. If the counts match, the receiver can assume that the transmission arrived intact.







Chip
A fingernail-sized piece of material, usually silicon, in which tiny amounts of other elements with desired electronic properties are deposited and etched to form integrated circuits. These tiny chips are the key to the microelectronic revolution in computers. Also called microchips.







Circuit
A connection between endpoints over a physical medium.







Circuit Simulation
A way for a designer to test the behavior of a circuit on a computer, before it is actually made.







Circuit Switching
The process of setting up and keeping a circuit open between two or more users, such that the users have exclusive and full use of the circuit until the connection is released.







Circuit-Level Inverse Multiplexing
A method of inverse multiplexing in which the inverse mux slices the data stream into equal portions, and transmits each portion over an available circuit. The receiving end adjusts for network-induced delay and reassembles the data packets into their proper order. The AIM and BONDING protocols define how circuit-level inverse multiplexing works. Applications that require transparent digital circuits, such as videoconferencing, nailed-up backup and overflow, and bulk file transfer applications, use circuit-level multiplexing.







Circuit-Switched Network
A dedicated connection between both ends that is busy for the duration of the call.







Circuit-switched Line
A temporary connection, like a telephone call. A temporary connection can be made to a variety of sites to handle occasional data-transfer needs or to provide additional bandwidth.







Cladding
In fiber optics technology, the plastic or glass jacket that protects an optical fiber. It prevents loss of signal carried by the fiber by reflecting light back into the fiber's core.







Clean Room
A sealed area in a semiconductor manufacturing plant in which humidity, temperature, number of air particles, and other factors are controlled.







Client
A software program on one computer that contacts and obtains data from a server software program running on another computer.







Client-Server Computing
A form of shared or distributed computing in which tasks and computing power are split between workstations/PCs (the "clients") and one or more larger computers (the "servers") on a network.







Clock Cycle
The internal pulse of a chip or a computer, used to schedule its operations. Generally, a faster clock cycle translates to faster processing.







Coaxial Cable
A transmission medium consisting of insulated core surrounded by a braided shield.







Coaxial Network
A network that uses coaxial cable.







Coaxial Run
Any length of coaxial cable that connects devices







Code Division Multiple Access (CDMA)
CDMA is a digital wireless transmission technique that uses mathematical codes, instead of frequencies or time slots, to transmit information. CDMA is a leading digital standard.







Coder/Decoder (CODEC)
An electronic circuit that converts analog voice signals into digital signals and vise versa.







Collector
One side of a transistor. In a NPN transistor the electrons flow from emitter to collector. In PNP transistor the electrons flow from collector to emitter.
See for details.







Command Line Interface
The visual appearance and command input conventions that enable system administrators and system operators to configure, monitor, and manage the connected nodes in a data network.







Committed Burst (Bc)
Bc is the maximum number of data bits that the network agrees to transfer, during the time interval specified by Tc, under normal conditions. The Bc value is defined for each permanent virtual circuit (PVC).







Committed Information Rate (CIR)
The rate at which the network agrees to transfer information under normal conditions. The rate is averaged over the minimum increment of time specified by Tc.







Common Carrier
A company like AT&T that provides dial-up network access to users and devices without network interface.







Common Channel Signaling Version 7 (CCS 7)
Also known as Signaling System 7, a network standard that transmits call-handling information for telecom calls over a separate channel than that taken by the calls.







Common Part (CP)
The CP is the portion of the signaling ATM adaptation layer (SAAL) that represents the functionality common to all users requiring a connection-oriented, variable bit-rate information transfer. It provides uninsured information transfer and mechanism for detecting corruption of information carried in the SAAL frames.







Communications Satellite
A manufactured object that orbits the earth, exchanging communications information with satellite dishes linked to earth-based stations.







Communications Server
A remote access device with one or more asynchronous ports that provides dial-up network access to users and devices without network interfaces.







Community Antenna Television (CATV)
A baseband network.







Community-Antenna Television or Community-Access Television (CATV)
Originally referred to as a system that distributes television signals in locations where distances, terrain, or situations that would interfere with or weaken the TV signals; now broadly applied to all TV service distributed over cable.







Competitive Access Provider (CAP)
A CAP is a business that competes with the local telephone company in providing clients with access to services. For example, a cable company that offers high-speed data communications services is a CAP.







Competitive Local Exchange Carrier (CLEC)
A CLEC is a company that competes with the established local telephone company by providing its own network and switching services.







Composite Fiber Cable
A fiber optic cable with copper conducts included for DC transmission.







Compression
Compression is a technique that reduces the quantity of bandwidth or bits required to encode a block of information. Compression saves transmission time and capacity, and can free up storage space on in-demand data lines. Compressed data can be compromised in quality, but the advantages of bandwidth savings are frequently worth the trade-off. Compression is not yet standardized. Ascend equipment can perform high compression rates with its own equipment at both ends of a call, using its own brand of compression.







Compression Protocol
A protocol that can improve Internet transmission speeds dramatically. The protocol squeezes a data file at the sending modem to a much leaner size, reducing it to as much as 40 percent. At the receiving modem, the file is restored to its original size, a process known as decompression.
See for more info.







Computer Aided Design/computer Aided Manufacturing (CAD/CAM)
A computer and its related software and terminals used to design and manufacture things. CAD terminals are often run over LANs and/or WANs.







Computer Supported Telephone Application
A standard from the European Computer Manufacturers Association for linking computers to telephone systems.







Computer Telephony Integration (CTI)
Technology that connects a computer to a telephone so they share information and commands. Events from the computer can trigger events on the telephone system, and vice versa.







Computer-Aided Design (CAD)
A form of automated design, CAD uses hardware and software computer tools to design and test chips, electronic circuits, and other devices.







Conductor
Any material, such as aluminum or copper, capable of transmitting electric current.







Configuration File
An unformatted ASCII file that stores initialization information for an application.







Congestion Control
techniques used in a network to prevent and react to temporary excessive demand for resources.







Connection Administration Control (CAC)
In an asynchronous transfer mode (ATM) transmission, CAC consists of tasks performed by the network in order to determine whether to accept or reject a request for a connection or for reallocation of bandwidth.







Connection Oriented Transmission
Data transmission that is analogous to mailing your letters.







Connection Profile
Information about a remote network you are authorized to connect to by dialing out. Connection profiles contain all the information the Pipeline needs to manage authentication and data transfers. Answer profiles contain incoming connection details.







Connection-oriented Service
In communications, a service that requires a direct connection or circuit between two nodes in order to transmit. Once set up, the circuit is dedicated to that single transmission until the session is completed. The most common connection-oriented network is the voice telephone system.







Connectionless Service
A characteristic of the packet delivery service that treats each packet as a separate entity which contains a source and destination address.







Connectivity
The degree to which a given computer or application can interoperate with other network components.







Consortium of European Posts and Telegraphs
An organization that represents the telephone operations and postal operations of European countries. Among other things, this group establishes standards to insure the interoperability of circuits and equipment among European nations.







Control-Lead Dialing
The initiation of a dialed call over the network using signals on leads within the interface cable between an application and the network access equipment. Thus, an application instructs the network access equipment to dial a call by toggling one or more leads within the cable between the application and the network access equipment.







Controlled Environment Vault (CEV)
An underground enclosure for network equipment such as batteries, electronics, terminating, and cross-connection equipment.







Conventional Current
Electric current, which flows in the opposite direction of electron flow, in an electronic component.







Convergence
The gradual blurring of telecommunications, computers, cable and the Internet into a single system.







Convergence Sublayer (CS)
CS is a sublayer of ATM adaptation layer (AAL). Its primary purpose is to encapsulate the data arriving from the higher layers and to prepare the data for segmentation.







Cookie
A small data file written to your hard drive by some websites when you view them in your browser. It provides a way for the sending website to keep track of a user's Web patterns and preferences and to store them on the user's hard disk.







Copper Data Distribution Interface (CDDI)
CDDI is the copper equivalent of FDDI. It is a network architecture that supports transmission rates of up to 100 Mbps over unshielded twisted pair (UTP) cable, with a maximum length of 100 meters.







Core
The underlying architecture of a chip that controls its functioning.







Core Networking
The core network consists of a comprehensive mix of switching and access products, data networking systems for service providers, optical networking products, communications software and engineering services. These products and systems form the hub of communications networks, linking together a variety of communications devices such as switches and routers in both the core and at the edge closer to the end user, allowing for the exchange of information in any type of medium - voice, data and video.







Cost Management
See Call Filters.







Crossover Cable
A cable with wires that "cross over," so the terminating ends of the cable have opposite wire assignments. (Contrast with straight-through cable).







Crosstalk
Unwanted transfer of energy or interference from one circuit to another.







Custom Local Area Signaling Service (CLASS)
Custom calling features such as automatic call back, automatic number recall, caller ID, call tracing, multi-distinctive ringing.







Customer Network Management (CNM)
CNM gives enterprise network managers, carrier partners, internal employees, and service provider customers access and control over their portion of the public infrastructure.







Customer Premises Equipment (CPE)
Distinguishes equipment owned subscribers from that owned by network service providers.







Cyclic Redundancy Check (CRC)
A technique in which polynomials are used for error correction.







Cyclical Redundancy Check (CRC)
A term understood by most providers. Many stand-alone channel service units (CSUs) have an LED that will blink with CRC, or you can query the CRCs via the error statistics on a CSU. All error detection methods involve some form of redundancy, bits or sequences that can inform the system of the presence of errors.