Glossary
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BAYONET NUT COUPLE (BNC) CONNECTOR—A 10BASE2 thin coax
connector with push-on BNC locking lug that quickly locks into place with a
half twist.
BIT RATE (BR)—This is the rate of data throughput on the medium in bits
per second. Ethernet specifies 10 million bits per second.
BRANCH CABLE—The AUI cable interconnecting the DTE and MAU system
components also known as a Drop cable.
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 to detect
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 and 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 MAU.
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 and terminated at each end in its characteristic impedance.
COLLISION—An unwanted condition that results from concurrent
transmissions on the physical medium.
COLLISION PRESENCE—A signal provided by the PLS to the PMA
sublayer (within the physical layer) to indicate that multiple stations are
contending for access to the transmission 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 to the baseband transmission system.
CROSSOVER—Wiring is 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 would have 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 with no receiver. Therefore, the crossover cable crosses the TD pair
with the RD pair of UTP cable connecting 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 RS232 specification a
module, such as a modem, for connecting a DTE to other equipment. A repeater
connected to a terminal or workstation for Omega local management use is
wired as a DCE.
