TurboStack Hubs with Management
71
DEPARTMENT CONCENTRATOR—Hub that provides a large number of
workstation connections. The term department concentrator refers to multiple
repeaters housed in an AT-CTS 7-slot or AT-C36C 8-slot chassis. See Hub/
Repeater, Repeater.
DIX CONNECTOR—See D-Sub Connector
FOIRL — A fiber optic standard that allows up to 1,000 meters (3,280 ft.) of
multimode duplex fiber optic cable in a point-to-point link.
HARMONICA ADAPTER—This adapter provides a simple way to convert
the 50-pin Telco connection to RJ45 connections. See AT-Adapt-2.
HEARTBEAT—See SQE
HOT SWAPPING— The process of replacing a hub module without bringing
down the network. This process occurs when you slide an active module into a
fully powered-up concentrator, replacing a failed module.
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 RJ45 receptacle at the hub would wire
pin-to-pin to the RJ45 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
sent by the repeater to all ports. The jam signal consists of 96 bits of alternating
1s and 0s. Its 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.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
