Specifications

Glossary
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swell and compress the median nerve, which car-
ries impulses from the brain to the hand, causing
numbness, weakness, tingling, and burning in the
fingers and hands. Computer users get carpal tun-
nel syndrome primarily from improper keyboard
ergonomics that result in undue strain on the wrist
and hand.
carrier A continuous frequency signal capable of
being either modulated or impressed with another
information-carrying signal. The reference signal
used for the transmission or reception of data. The
most common use of this signal with computers
involves modem communications over phone
lines. The carrier is used as a signal on which the
information is superimposed.
carrier detect signal A modem interface signal
that indicates to the attached data terminal equip-
ment (DTE) that it is receiving a signal from the
distant modem. Defined in the RS-232 specifica-
tion. Same as the received line-signal detector.
CAT Short for category, CAT describes the
ANSI/EIA 568 wiring standards used for data trans-
mission. The most common CAT standards include
CAT 3 (16Mbps maximum data rate, suitable for
10BASE-T Ethernet) and CAT 5 (used for 100BASE-T
Fast Ethernet or 1000BASE-T Gigabit Ethernet).
cathode ray tube (CRT) A device that contains
electrodes surrounded by a glass sphere or cylinder
and displays information by creating a beam of
electrons that strike a phosphor coating inside the
display unit. This device is most commonly used in
computer monitors and terminals.
CAV (constant angular velocity) An optical
disk recording format in which the data is recorded
on the disk in concentric circles. CAV disks are
rotated at a constant speed. This is similar to the
recording technique used on floppy disk drives.
CAV limits the total recorded capacity compared to
CLV (constant linear velocity), which also is used in
optical recording. See also CLV.
CCITT An acronym for the Comité Consultatif
International de Télégraphique et Téléphonique (in
English, the International Telegraph and Telephone
Consultative Committee or the Consultative
Committee for International Telegraph and
Telephone). Renamed ITU (International
Telecommunications Union). See also ITU.
CCS (common command set) A set of SCSI
commands specified in the ANSI SCSI-1 Standard
X3.131-1986 Addendum 4.B. All SCSI devices must
be capable of using the CCS to be fully compatible
with the ANSI SCSI-1 standard.
CD (compact disc or compact audio disc) A
4.75" (12cm) optical disc that contains information
encoded digitally in the constant linear velocity
(CLV) format. This popular format for high-fidelity
music offers 90 decibels signal/noise ratio, 74 min-
utes of digital sound, and no degradation of quality
from playback. The standards for this format
(developed by NV Philips and Sony Corporation)
are known as the Red Book. The official (and rarely
used) designation for the audio-only format is CD-
DA (compact disc-digital audio). The simple audio
format is also known as CD-A (compact disc-audio).
A smaller (3") version of the CD is known as CD-3.
CD burner Refers to either a CD-R or CD-RW
drive. See also DVD burner.
CD+G (Compact Disc+Graphics) A CD format
that includes extended graphics capabilities as writ-
ten into the original CD-ROM specifications.
Includes limited video graphics encoded into the
CD subcode area. Originally developed and mar-
keted by Warner New Media (later Time Warner
Interactive), it’s a popular choice for self-contained
karaoke systems.
CD-I (Compact Disc-Interactive) A compact
disc format released in October 1991 that provides
audio, digital data, still graphics, and motion video.
The standards for this format (developed by NV
Philips and Sony Corporation) are known as the
Green Book. CD-I did not catch on with consumers
and is now considered obsolete.
CD+MIDI (Compact Disc+Musical
Instrument Digital Interface) A CD format
that adds to the CD+G format digital audio, graph-
ics information, and musical instrument digital
interface (MIDI) specifications and capabilities.
Originally developed and marketed by Warner New
Media (later Time Warner Interactive).
CD-R (Compact Disc-Recordable, sometimes
called CD-writable) CD-R discs are compact
discs that can be recorded and read as many times
as desired. CD-R is part of the Orange Book stan-
dard defined by ISO. CD-R technology is used for
Appendix A
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