Glossary
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BAYONET NUT COUPLE (BNC) CONNECTOR—A 10BASE2 thin coax
connector with push-on BNC locking lug. This lug quickly locks into place with
a half twist.
BIT RATE (BR)—The rate of data throughput on the medium in bits per
second. Ethernet specifies 10 million bits per second.
BIT TIME—The duration of one bit symbol (1/BR). Ethernet specifies a bit
time of 100 ns.
CARRIER SENSE—In a LAN, an ongoing activity of a data station that
detects whether another station is transmitting.
CARRIER SENSE MULTIPLE ACCESS with COLLISION DETECT
(CSMA/CD)—This is the access method employed by IEEE 802.3 LAN
transceivers, by which multiple stations compete for use of the transmission
medium (coax cable) for data packet transmission. It provides for a level of
error detection should that transmission be corrupted or impeded by
contention for the transmission medium.
COAX SEGMENT—A segment of Ethernet cable that contains MAUs.
COAXIAL CABLE—A two-conductor (center conductor, shield system),
concentric, constant-impedance transmission line used as the trunk medium in
the baseband system.
COAXIAL CABLE SEGMENT—A length of coaxial cable sections and
coaxial connectors, terminated at each end in its characteristic impedance.
COLLISION—An unwanted condition that results from concurrent
transmissions on the physical medium.
COMPATIBILITY INTERFACE—The MDI coaxial cable interface and the
AUI branch cable interface, the two points at which hardware compatibility is
defined to allow connection of independently designed and manufactured
components with the baseband transmission system.
CROSSOVER—Wiring used when connecting a 10BASE-T MAU to another
10BASE-T MAU or a 10BASE-T hub to another 10BASE-T hub. For example,
one 10BASE-T MAU has the TD pair on the same pins as another 10BASE-T
MAU. If pins were wired straight, there would be two transmitters on one pair
and no receiver. As a solution, the crossover cable crosses the TD pair with the
RD pair, to connect the TD pins on one end to the RD pins at the other end.
D-SUB CONNECTOR—The AUI cable uses 15-pin D-sub connectors. “D”
refers to the shape of the connector shell. Also called miniature D, DB15, or
DIX connectors.
DATA COMMUNICATION EQUIPMENT (DCE)—In RS-232 specification,
a module, such as a modem, for connecting a DTE to other equipment. A
repeater connected to a terminal or workstation for Omega management use is
wired as a DCE.
DATA TERMINAL EQUIPMENT (DTE)—In RS-232 specification, a module
typically at the end of a segment (i.e., uninterrupted length of Ethernet cable).
The DTE could be an Ethernet workstation, repeater or bridge.
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