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Appendix B
Glossary
10BASE2—Also called thinnet Ethernet, thinnet or CheaperNet, a 10 MHz base band
specification. Cable impedance is 50
Ω
and maximum coaxial segment length is 185
meters (607 ft.).
10BASE5—Also called thick Ethernet, a 10 MHz baseband specification. Cable
impedance is 50
Ω
and maximum coaxial segment is 500 meters (1,640 ft.). The cable is
commonly referred to as yellow cable. Thick Ethernet cable is typically used as a trunk
or backbone path of the network.
10BASE-FL—IEEE 802.3 Fiber Optic Ethernet. A fiber optic standard that allows up to
2,000 meters (6,560 ft.) of multimode duplex fiber optic cable in a point-to-point link.
10BASE-T—IEEE 802.3 UTP Ethernet. Using low cost Level 3 or better UTP wiring,
100 meters (328 ft.) of point-to-point link segments are possible. Uses RJ45 connectors
and sometimes 50-pin AMP connectors to a patch panel. Runs at 10 MHz.
50-PIN TELCO (RJ21)—This connector is very common in 10BASE-T wiring. As
opposed to the RJ45 connector, the 50-pin Telco connector concentrates up to 12 UTP
connections onto one connection. This concentration of UTP ports is then broken out for
connection to a punch-down block inside a building’s wiring closet. 50-pin Telco
connections provide a very clean, uncluttered interface to the building’s wiring.
AT-ADAPT-2— A harmonica-style adapter that allows direct conversion from a 50-pin
Telco connector to RJ45 receptacles.
ATTACHMENT UNIT INTERFACE (AUI)—Connection between a MAU
(transceiver) and a DTE (typically a workstation). Includes a 15-pin D-sub connector
and sometimes a 15-conductor twisted pair cable. Maximum length is
50 meters (164 ft.).
BACKUP MODULE— A repeater that behaves as the management module when the
Master fails in a department concentrator.
BASEBAND COAXIAL SYSTEM—A system whereby information is directly encoded
and impressed on the coaxial transmission medium. At any point on the medium, only
one information signal at a time can be present without disruption.
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.
