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CAD (computer-aided design)
CAD software generally runs on workstations and is a tool used to provide three-dimensional, on-screen design for everything from buildings to automobiles to clothing.

CAE
Computer-aided engineering.

Call Automation
Part of the telephone equipment revolution that includes voice mail, automated sending and receiving of faxes and the ability for customers to place orders and gather information by using a touch-tone telephone to access sophisticated databases. (See "Voice Mail" below.)

CAM
Computer-aided manufacturing.

Carrier
The basic radio, television or telephony center of transmit signal is known as a carrier. The carrier in an analog signal is modulated by varying volume or shifting frequency up or down in relation to the incoming signal. Satellite carriers operating in the analog mode are usually frequency modulated.

CDMA Code Division Multiple Access)
A multiple-access scheme where stations use spread-spectrum modulations and orthogonal codes to avoid interfering with one another.

Cell
Geographic unit of a wireless phone system, from whence came the term "cellular." Regions are divided into small cells, each equipped with a low-powered radio transmitter. When a mobile phone moves from one cell to another, phone calls are handed off.

Cellular
Technology that sends analog or digital transmissions from transmitters that have areas of coverage called cells.

Cellular Digital Package Data (CDPD)
A form of data that allows telecommunications companies to distribute data among the cells, or sections, of their networks to users.

CGI (Common Gateway Interface)
A set of guidelines that determines the manner in which a web server receives and sends information to and from software on the same machine.

CGI-BIN
The frequently used name of a directory on a web server where CGI programs exist.

Circuit Switching
A method used by wireless carriers that lets a user connect to a network or the Internet by dialing in, as with a traditional phone line.

Client/server computing
An interconnected network environment in which servers distribute processing power and software applications to workstations.

Client/Server (networking)
A way of running a large computer setup. The "Server" is the host computer that acts as the central holding ground for files, databases and application software. The "Clients" are all of the PCs connected to the network that share data with the Server. This is a vast change from the networks of the past that were connected to expensive, complicated "mainframe" computers.

Coaxial cable
A type of cable widely used to transmit telephone and broadcast traffic. The distinguishing feature is an inner strand of wires carrying a signal surrounded by an insulator that in turn is surrounded by another conductor that serves as the ground.

Co-location
Refers to having a server belonging to one group that is physically located on a network belonging to another group. Co-location is usually practiced for security reasons.

Compression
A technology in which a communications signal is squeezed so that it uses less bandwidth (or capacity) than it normally would. This saves storage space and shortens transfer time. The original data is decompressed when read back into memory.

Code Division Multiple Access (CDMA)
A method of allocating bandwidth that uses mathematical codes to distinguish between multiple transmissions being carried at one time on a single wireless signal.

Computer architecture
The entire blueprint of a computer system.

Content rating
Labels that identify files' contents so that filters can prevent certain types of content from being accessed.

Content security
A computing infrastructure that prevents information from being released by or within a company that compromises its security.

Cookie
Information that websites place on users' hard drives to identify users and record their usage patterns. Often used in on-line selling points.

Crash
The sudden failure of a software application or operating system or of a hardware device such as a hard disk drive.

Cryptography
The practice of coding in which data is encrypted and decrypted using an algorithm.

Cyber
This term is commonly used as a prefix to things and ideas that are being made more prevalent in society through the spread of computers and technology.

Cyberspace
This term refers to the entire realm of information available through computer networks.