Allied Telesis AT-MR420T, Installation Manual

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Glossary
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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 (Transmitted Data) 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 (Ready Data) 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.
DIX CONNECTOR—See D-Sub Connector
HEARTBEAT—See Signal Quality Error
HOUSE WIRING—House wiring is the existing wiring inside a building. This
wiring generally originates from one or more wiring closets, such as a telephone
room. Some older buildings may have wiring unsuitable for 10 megabit data
rates. In these circumstances, it is recommended that the wiring be tested with
a 10Base-T signal/wire tester.
MRx20T(UTP)Ver6_Book Page 32 Thursday, April 3, 1997 5:18 PM