Glossary
72
LINK TEST—In 10BASE-T Ethernet, there is a link test function that
validates the UTP link. This consists of a pulse transmitted from point A on one
pair that is validated at point B. Point B also transmits a pulse on the second
pair to be validated by point A. These pulses occur during media idle states (in
between packets).
MANAGED MODULE— An intelligent repeater in a department
concentrator chassis that makes management data available to the Master.
MANAGEMENT AGENT—Software that is used to view hub activity and set
hub variables.
MASTER—A repeater in the topmost position in a department concentrator
chassis that contains and downloads the management agent software to
Backup and Slave modules. The Master contains the only active image of the
management agent and controls the management functions of the Backup and
Slaves.
MAU—See Medium Attachment Unit
MAU-to-MAU, HUB-to-HUB WIRING—10BASE-T MAU-to-MAU or hub-to-
hub wiring generally requires a crossover cable located somewhere along the
UTP cable run. This may commonly occur at the punch-down block or between
the RJ45 wall receptacle and the workstation.
MAU/TRANSCEIVER—An Ethernet transceiver is a MAU. A 10BASE-T
MAU interfaces the UTP media to an AUI port on a workstation, repeater,
bridge or other Ethernet device.
MDI/MDI-X—See Medium Dependent Interface
MEDIUM ATTACHMENT UNIT (MAU)—In a LAN, a device used in a data
station to couple the DTE to the transmission medium.
MEDIUM DEPENDENT INTERFACE (MDI)—The mechanical and
electrical interface between a hub and a transceiver (MAU). MDI-X is another
version of the interface that enables hubs to connect using different pin-outs,
thereby avoiding conflicts that occur when receiving and transmitting packets
use the same pin-out.
MODULE—A single repeater when it is mounted with other repeaters in an
AT-CTS or AT-C36 department concentrator chassis.
N-SERIES—A barrel-shaped, threaded connector used on 10BASE5 (thick
Ethernet) coaxial cable.
PATCH PANEL—A 10BASE-T patch panel may be used between a punch-
down block and a UTP workstation. The patch panel generally has a female
RJ45 connector on the front for each workstation and a Telco (RJ21) connector
on the back; through the RJ21 connector, the patch panel is wired to a punch-
down block. This provides a convenient way for the installer or network
manager to connect the hub 10BASE-T ports into the desired building
locations.
POLARITY CORRECTION—Many 10BASE-T UTP ports have a polarity
correction function. If the UTP wiring has RD- and RD+ inadvertently crossed,
the polarity correction function will sample the signal and electrically swap the
wires. If the TD- and TD+ wires are crossed, the correction would occur at the
MAU on the other end of the UTP link. This occurs within a single pair and
should not be confused with the crossover cable.
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