Specifications

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Glossary
NEXT (Near-End Crosstalk): Unwanted electrical noise
from a transmitter (near end) into a neighboring
wire pair measured at the near end.
Noise: Random electrical signals, generated by
circuit components or by natural disturbances,
that corrupt the data transmissions by introducing
errors.
Nominal Velocity of Propagation: The ratio of signal
speed to the velocity of light in a vacuum.
Off-Premise Station: A PBX station in a location
separated from the main PBX.
Off-site: A location that is not in the building
or campus being referred to.
On-site: A location that is in the building or
on the campus being referred to.
Open Office: A floor space of offices separated by
moveable furniture or partitions rather than walls.
Optical Fiber: Any filament or fiber, made of
dielectric materials, that is used to transmit
laser or LED-generated signals.
OPX (Off-Premise Extensions): A leased line from the
telephone company that enables telephones at a
distant location to operate as if they were directly
connected to a local PBX.
Outlet (Telecommunications): A connector in a wall
or partition that provides a connection point to
power, phone, or network services.
Patch Cord: A short cable with a plug on each end
that is used to make a cross-connection.
Patch Panel: A panel, usually rackmountable, that
contains the connecting hardware to join multiple
cables.
Pathway: An open or closed channel used for the
routing of cables.
PBX (Private Branch eXchange): A device that
provides private local voice switching and voice-
related services within the private network.
Permanent Link: A segment or transmission path
between two points not including connecting
equipment and patch cable. Used for testing.
See Link. Contrast with Channel.
Plenum-Rated Cables: Cables with low-smoke
insulation approved by the National Electrical
Code for installation in air spaces (“plenums”).
PoE (Power over Ethernet): A technology in which
electrical power and data are transmitted over
standard twisted-pair cable in an Ethernet
network. It’s particularly useful for wireless
access points, security cameras, and other
devices where power is not readily accessible.
Premise Cabling, Premise Wiring: Existing cable or
wiring installed in a building or campus.
Propagation Delay: The time it takes a signal to travel
from one point to another over a transmission
channel.
PS-AACRF (Power Sum Attenuation to Crosstalk
Ratio, Far End): The sum of signal coupling from
multiple pairs of disturbing pairs to a disturbed pair
in another cable measured at the far-end and
relative to the received signal level in the disturbed
pair at the far-end. Formerly PS-AELFEXT.
PS-ACR (Power Sum Attenuation to Crosstalk Ratio):
A sum derived by subtracting the attenuation
(insertion loss) from the power sum near-end
crosstalk.
PS-AELFEXT (Power Sum Attenuation to Crosstalk
Ratio, Far End): See PS-AACRF.
PS-AFEXT (Power Sum Alien Far-End Crosstalk):
The sum of signal coupling from multiple near-
end disturbing cable pairs to a disturbed pair in
a neighboring cable, measured at the far end.
PS-ANEXT (Power Sum Alien Near-End Crosstalk):
The sum of signal coupling from multiple
disturbing cable pairs to a disturbed pair in a
neighboring cable, measured at the near end.
PS-ELFEXT (Power Sum Equal-Level Far-End
Crosstalk): The sum of unwanted signals from
multiple transmitters (near end) into a pair
measured at the far end, and relative to the
received signal level.
PS-NEXT (Power Sum Near-End Crosstalk): The
sum of unwanted electrical noise from multiple
transmitters (near end) into neighboring wire pairs
measured at the near end.
Pull Box: A conduit or raceway box with an access
cover to facilitate feeding cables around corners.
Pulling Tension: The amount of pull placed on a cable
during installation. Measured in pounds.
Punchdown Block: A plastic block with contacts used
for cross-connecting UTP Cable. Generally used
with phone lines.
Raceway: An enclosed cable-distribution pathway.
Rackmount: Components that are built to fit in a
metal frame that can be installed in a cabinet;
usually 19" wide.
Rack Unit: A measurement of vertical rack space.
One rack unit is equal to 1.75".
Raised Floor: A modular floor constructed over the
building’s floor to facilitate cabling and cooling.
Return Loss: The measure of a signal reflected back
toward the transmitter as a result of impedance
differences in the cabling.
Reversed Pair: A cable-termination error in which
conductors are in the wrong order.
RFI (Radio-Frequency Interference): Interference with
broadcast and data signals caused by radiation in
the radio-frequency band of the electromagnetic
spectrum.
Riser Cable: Backbone cable rated for vertical
applications.
RJ-11: A wiring designation with 4- or 6-wire modular
connectors; commonly used for standard
telephone lines.
RJ-45: A wiring designation with 8-wire modular
connectors.
RJ-48C: An 8-wire modular connector used for the
DSX-1 interface.
Roaming: In wireless, the ability to move seamlessly
from one access point coverage area to another
with no loss in connectivity.
SC: A push-pull type single-channel fiber optic
connector.
Server: A computer or processor that holds
applications, files, or memory shared by users
on a network.
S/FTP (Shielded/Foiled Twisted Pair): A twisted-pair
cable with an overall shield and individual foiled
twisted pairs.
Single-Mode Fiber: An optical fiber that transmits
light only in a single optical path, achieving very
high bandwidth over long distances.
ST
®
: A registered trademark for a bayonet-style, single-
channel fiber optic connector invented by AT&T
®
.
STP (Shielded Twisted Pair): Cabling that consists of
twisted pairs with a foil and/or braided shield to
minimize EMI/RFI.
Straight-Through Pinning: Cable configuration that
has connectors wired, pin for pin (Pin 1 to Pin 1,
Pin 2 to Pin 2, etc.).
Strain Relief: Any means of relieving an installed
cable of supporting its own weight.
Structured Cabling System: A planned, logical
infrastructure of telecommunications cabling
installed to industry standards.
Surge Protector: A device that protects computers
from excessive voltage and current in the
power line.
T1: A digital carrier facility used to transmit
a DS-1 formatted digital signal at 1.544 Mbps
that can be divided into 24 separate DS0 channels
at either 56 or 64 kbps.
Telecommunications Room: The area that
houses telecommunications equipment, cable
terminations, and horizontal cross-connects.
Usually serves one floor in a building. Formerly
Wiring Closet.
Terminal Block: A junction point for multiple
connections within a cable to be spliced or
manipulated.
Termination: Placement of a connector on a cable
or distribution panel.
Terminator: A device that provides termination for
a signal line, or several signal lines, at the end
of a cable.
TIA (Telecommunications Industry Association): Best
known for developing cabling standards with
the EIA, it’s the leading trade association for the
information, communications, and entertainment
technology industry. The TIA provides standards
development and represents the communications
sector of the EIA. See EIA.
Tight-Buffered Fiber Cable: An indoor cable with
multi-fibers, each of which has a 900-micron
jacket. Contrast with Loose-Tube Fiber Cable.
Twisted Pair: A cable with pairs of two conductors
twisted together.
UTP (Unshielded Twisted Pair): A cable with one or
more pairs of twisted conductors bundled within
the same outer PVC covering.
VCSEL (Vertical Cavity Surface Emitting Laser):
A small laser used for emitting optical power
for multimode fiber.
VoIP (Voice over Internet Protocol): Technology
for transmitting voice conversations (telephone
calls) over the Internet or any other data network
using the Internet Protocol, such as a corporate
Intranet. VoIP converts analog voice data into
digital packets for transmission.
VPN (Virtual Private Network): A means of
segmenting a network and prioritizing traffic
of a selected set of users.
WAN (Wide-Area Network): A data communications
network spread across a wide geographic area
and incorporating a large number of users.
Contrast with Enterprise Network.
Wireless: Communication of data, voice, and video
signals over radio frequencies.
Wireless Access Point (WAP): A device that links
wireless devices to a network. Also known as
an access point (AP) or base station.
Wireless Internet Service Provider (WISP): An Internet
provider that specializes in providing wireless
Internet access, often in hotspots in public areas,
such as airports.
Wireless IP: Wireless IP (Internet Protocol) is the
packet protocol standard for sending wireless
data over the Internet.
Wireless LAN (WLAN): A local area network that
incorporates wireless transmission—usually using
one of the 802.11 Ethernet standards— in place of
cable. Wireless Ethernet standards, such as 802.11,
differ from standard 802.3 wired Ethernet only
at OSI Layers 1 and 2, making them interoperable
with standard wired Ethernet.
Wire Map: A test that checks cable termination by
identifying miswiring, such as shorts, continuity,
split pairs, etc.
Wiring Closet: The area that houses tele-
communications equipment, cable terminations,
and horizontal cross-connects. Usually serves
one floor in a building. An older term. Now
Telecommunications Room.
Work Area: The cabling between the wall outlet and
user equipment, such as PCs, printers, and phones.
Xchange: Often a term for the Central Office, it’s a
unit established by a common carrier to administer
communications services in a specific geographical
area, such as a city. It consists of one or more
Central Offices as well as the equipment used.
xDSL: A term that encompasses a broad range of
digital subscriber line (DSL) services. These DSL-
based services, which operate over existing
telephone lines, provide users with speeds
significantly faster than those of 56-kbps
analog modems.
Zone Cabling: The cabling from the horizontal cross-
connect to an office area.