bination of hue and saturation, independent of intensity. The relative proportion of R, G and B determines the color perceived. chrominance The combination of hue and saturation that, taken together with luminance (brightness), define color. Commission Internationale de l'Eclairage, an international body that specifies colors based on their frequencies. Common Intermediate Format, an optional part of the ITU-T's H.261 and H.263 standards. CIF specifies 288 non-interlaced luminance lines, that each contain 352 pixels and 144 chrominance lines that contain 176 pixels. CIF is to be sent at frame rates of 7.5, 10, 15 or 30 per second. When operating with CIF, the number of bits that result cannot exceed 256 K bits (where K equals 1024). Cinepak A proprietary software-based compression method developed by Radius for use on Apple Macintosh computers. Cinepak video is sent at 15 fps, with a 240-pixel high by 320-pixel wide resolution. circuit In telecommunications, pair of channels, which together provide bi-directional communications. A circuit includes the associated terminal equipment at the carrier's switching center. circuit switching The process of establishing a connection for the purpose of communication in which the full use of the circuit is guaranteed to the parties or devices that are exchanging information. After the communication has ended, the connection is released for use by others. CISSP (ISC) - grants the Certified Information Systems Security Practitioner designation to information systems security practitioners for passing a rigorous CISSP examination and subscribing to the (ISC). Code of Video Communication: the Whole Picture Ethics. Additional information is available at http://www.isc2.org/welcome.html CIVDL Collaboration for Interactive Visual Distance Learning. A collaborative effort by 10 leading US universities that uses dial-up videoconferencing technology for the delivery of engineering programs. clearchannel The characteristic of a digital transmission path in which the circuit is entire b