AT-810SL Multiport Transceiver Fanout User Manual
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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.
HUB/REPEATER—A hub is a central signal distributor. It is used in a wiring topology
consisting of several point-to-point segments originating from a central point. The term
hub is often used interchangeably with the term repeater. Multiport 10Base-T, 10Base2
and fiber optic (10Base-FL, FOIRL) repeaters are considered hubs. See Repeater.
HUB-to-HUB WIRING—See MAU-to-MAU Wiring
HUB-to-MAU WIRING—UTP cables for 10Base-T hub-to-MAU or NIC cards are wired
straight-through. An RJ-45 receptacle at the hub would wire pin-to-pin to the RJ-45
receptacle at the MAU.
IMPEDANCE—An electrical characteristic of a circuit dealing with the combination of
the AC and DC resistance and the appearance of that resistance to attached circuits.
JABBER LOCK-UP—The MAU’s ability to automatically inhibit the transmit data
from reaching the medium if the transmit data time exceeds a specified duration. This
duration is in the range of 20 ms to 150 ms. Jabber lock-up protects the medium from
being overrun with data packets from a possibly defective device.
JAM—This is a term used to describe the collision reinforcement signal output by the
repeater to all ports. The jam signal consists of 96 bits of alternating 1s and 0s. The
purpose is to extend a collision sufficiently so that all devices cease transmitting.
JITTER—The shift of the data bit in respect to a standard clock cycle. Jitter is
undesirable and must be minimized.
LINK SEGMENT—The link segment of coaxial cable is a segment that has no MAU
devices, but links together two LAN devices such as repeaters.
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).
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 cross-over cable located somewhere along the UTP cable run. This
may commonly occur at the punch-down block or between the RJ-45 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.
