Allied Telesis AT-MR908TX - Manual (Page 50)

Glossary
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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. 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 to 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.
DEPARTMENT CONCENTRATOR—Hub that provides a large number of
workstation connections. The term department concentrator refers to multiple repeaters
housed in an AT-36C8 chassis. See Hub/Repeater, Repeater.
DIX CONNECTOR—See D-Sub Connector
HARMONICA ADAPTER—This adapter provides a simple way to convert the 50-pin
Telco connection to RJ-45 connections. See AT-Adapt-2.
HEARTBEAT—See SQE