Specifications

42
Black Box Guide to Structured Cabling
Section NameSection Name
Glossary
Distortion: The unwanted changes in signal or signal
shape that occur during transmission between
two points.
Distributed Architecture:
1) LAN architecture that uses a shared
communications medium such as bus or ring LANs.
2) Any computer system that uses shared access
methods.
Distribution Frame: Also called a distribution block,
it's a wallmounted structure for terminating
telephone wiring. It's used for permanent wires
from or at the telephone central office, where
cross-connections are made to extensions.
Download: To transmit a file from one computer
to another.
Downtime: The period during which computer
or network resources are unavailable to users
because of a system or component failure.
Downward Compatible: Also called backward
compatible. Refers to hardware or software that
is compatible with earlier versions.
Drain Wire: In a cable, an uninsulated conductor
laid over the component, or components, in
a foil-shield cable. Used as a ground connection.
Drop: A connection point between a communicating
device and a communications network; a single
connection (or node) on a multipoint line.
Drop Cable: A cable that connects the main network
cable, or bus, and the data terminal equipment
(DTE).
DSL (Digital Subscriber Line): A PSTN line that
provides high bandwidth for short distances
using copper cable.
Duplex: The ability of a device to simultaneously transmit
and receive signals through a common cable.
Duplex Cable: A fiber optic cable with two fibers
used for duplex transmission.
Dynamic Routing: A routing system that
automatically adapts to network topology
or traffic changes.
EIA (Electronic Industries Association): Founded
in 1924 as the Radio Manufacturing Association,
this membership organization sets standards for
consumer products and electronic components.
In 1988, it spun off its Information and Tele-
communications Technology Group into a
separate organization called the TIA. See TIA.
EIA/TIA 568: A wiring standard for commercial
buildings supported by both the Electronic
Industries Association and the Telecommunications
Industry Association, as well as the American
National Standards Institute.
ELFEXT (Equal-Level Far-End Crosstalk): The measure
of unwanted electrical noise from a transmitter
(near end) into a neighboring wire pair measured
at the far end, relative to the received signal
measured on the same pair.
EMI/RFI (Electromagnetic Interference/Radio-
Frequency Interference): Radiation of electric
and magnetic fields that interferes with signal
transmission or reception.
Enterprise Network: A privately owned and
maintained network connecting several key
areas in a company. Contrast with WAN.
Entity: A manageable device on a network.
Entrance Facility: A room or space that supports
the entry of inter- and intrabuilding cabling
from outside service providers.
Equalization: Technique used to reduce distortion
and compensate for signal loss (attenuation) over
long-distance communication lines.
Equipment Room: An environmentally controlled
room designed for housing network components,
telecommunications equipment, and main cross-
connects.
Error Checking, Control, Detection, or Correction:
Testing for accurate data transmission over a
communications network or internally within
the computer system.
Error Rate: Used to measure the effectiveness of
a communications channel, it’s the ratio of the
number of erroneous units of data to the total
number of units of data transmitted.
Ethernet: A local area network (LAN) developed by
Xerox
®
, Digital Equipment Corp., and Intel (IEEE
802.3). Ethernet connects up to 1024 nodes at
10 Mbps over twisted-pair, coax, and fiber optic
cable. When a station is ready to send, it transmits
its data packets onto the network, which is
common to all nodes. All stations “hear” the
data. The station that matches the destination
address in the packet responds, while the others
do nothing. Ethernet is a data-link protocol and
functions at the Physical and Data-Link levels
of the OSI model (Layers 1 and 2).
Ethernet Address: A unique 48-bit number
maintained by the IEEE and assigned to each
Ethernet network adapter.
Ethernet Meltdown: Usually a result of misrouted
packets, it's an event causing near or total
saturation in Ethernet applications.
F Connector: A coaxial connector commonly used
for video applications (CATV).
Fallback: The ability to default to an alternate line
or device in case the primary unit fails.
Ferrule: The hollow cylindrical tip of a fiber optic
connector that encloses the end of the fiber core.
FEXT (Far-End Crosstalk): Unwanted electrical noise
from a transmitter (near end) into a neighboring
wire pair measured at the far end.
Fiber Loss: The amount of signal attenuation
in a fiber optic transmission.
Fiber Optics: A technology that uses light to carry
digital information through small strands of glass.
Fire-Rated Poke Through: A cable entry suitable
for penetration through fire-rated floors.
Firewall: A network node set up as a boundary to
prevent traffic from one segment to cross over to
another. Firewalls are used to improve network
traffic, as well as for security purposes.
Floor Box: A metal box installed in the floor to serve
as an outlet or interconnection.
Flying Lead: A lead that exits the back of the
connector hood on the outside of the cable jacket.
It’s normally attached to the drain wire or shield
and then connected to the chassis of the switch,
modem, etc.
Full-Duplex (FDX): Simultaneous transmission of data
in both directions at once.
F/UTP (Foiled/Unshielded Twisted Pair): A unshielded
twisted-pair cable with an overall foil shield.
Gain: Increased signal power, usually the result
of amplification. Contrast with Attenuation.
Gigabit Ethernet: An Ethernet standard for data
transmission at 1 Gbps over copper or fiber.
Ground: An electrical connection or common
conductor that, at some point, connects
to the earth.
Ground Fault: The temporary current in the ground
line, caused by a failing electrical component or
interference from an external electrical source
such as a thunderstorm.
Ground Loop: An unwanted ground current flowing
back and forth between two devices that are
grounded at two or more points.
Half-Duplex (HDX): The transmission of data in both
directions, but only one direction at a time.
Horizontal Cabling: The cables and connectors that
connect the telecommunications room to the work
area. It includes the work area outlet, distribution
cable, and the connecting hardware.
Horizontal Cross-Connect: Where the horizontal
cabling joins to backbone cabling, usually in
a patch panel.
Hybrid Cable: A single cable that incorporates
different kinds of cable within the same sheath—
fiber and UTP, for instance.
Impedance: The resistance to the flow of alternating
current in a circuit.
Impedance Match: When the impedance of a
component or circuit is equal to the internal
impedance of the source. Ideally, impedances
should match to minimize reflection and
distortion.
In-Band Signaling: A transmission occurring in
the frequency range normally used for data
transmission.
Insertion Loss: A power loss that results from
inserting a component into a previously
continuous path or creating a splice in it.
Inside Wiring: In telephone deregulation, the
customer’s premise wiring; the wiring inside
a building.
Internet Telephony: Generic term describing various
methods of running voice calls over Internet
Protocol (IP).
Internetwork: Networks connected by routers and
other devices. This collection functions generally
as a single network.
Intranet: A network connecting a related set of
standard Internet protocols and files in HTML
format with employees using Internet browsers
in an organization’s network and within the
corporate firewalls.
IOP (Interoperability): Generic term describing
functional compatibility. IOP is the ability of
equipment from different manufacturers or
implementations to operate together.
ISP (Internet Service Provider):
A company that
provides Internet access.
Jacket: A cable’s protective insulated housing.
LC: A small, simplex fiber optic connector.
Link: A segment or transmission path between two
points not including connecting equipment and
patch cables. See Permanent Link.
Local Area Network (LAN): A data communications
system confined to a limited geographic area,
normally a single building or campus.
Loopback: A diagnostic test in which the transmitted
signal is returned to the sending device after passing
through all or part of a data communications link or
network. A loopback test compares the returned
signal with the transmitted signal.
Loose-Tube Fiber Cable: A fiber optic cable that has
multiple fibers inside a loose jacket and is usually
used outdoors. Many of these cables contain a gel
to cushion the fibers. Contrast with Tight-Buffered
Fiber Cable.
MACs (Moves, Adds, Changes): Administering
and physically moving, adding, and changing
components when users change locations in the
network. Refers to data and voice networks.
Main Cross-Connect (MC) : The cross-connect for first-
level backbone, entrance, and equipment cables.
MAN (Metropolitan-Area Network): A communica-
tions network that covers a geographic area, such
as a city or suburb.
Media Management: The ability to manage and the
process of managing different transmission media
used within the same network. It includes cable-
performance monitoring, cable-break detection,
and cable-routes planning.
Microbend: In fiber optics, a microscopic bend
in a glass fiber that causes it to lose the signal.
Mirroring: A complete, redundant duplicate of a
device including its programming and data, kept
active, current, and on-line as a fault-tolerant
backup system.
Mission-Critical: System resources whose failure could
seriously impair the ability of the system to function.
MT-RJ: A small duplex fiber optic connector that
resembles an RJ-45 connector.
Multimode Fiber: An optical fiber with a core
diameter of 50 to 100 microns. Its core causes
some distortion and provides less bandwidth
than single-mode fiber.
MUTOA (Multi-User Telecommunications Outlet
Assembly): A grouping of telecommunications
outlets that serves several individual work areas.
Network Architecture: The design of a
communications system, which includes the
hardware, software, access methods, protocols,
and the method of control.
Network Topology: The physical and logical
arrangement of the links and nodes within
a network.