Components

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GLOSSARY
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Glossary
Copper Glossary of Terms
ACR (Attenuation to Crosstalk Ratio): The difference
between attenuation and crosstalk, measured in
dB, at a given frequency. Important characteristic
in networking transmission to assure that signal
sent down a twisted pair is stronger at the receiving
end of the cable than are any interference signals
imposed on that same pair by crosstalk from
adjacent pairs.
ADSL (Asymmetric Digital Subscriber Line): Modems
attached to twisted pair copper wiring that transmit
from 1.5 Mbps to 9 Mbps downstream (to the
subscriber) and from 16 kbps to 800 kbps upstream,
depending on line distance.
Amplifier: Any device that intensifies a signal without
distorting the shape of the wave.
Analog: A signal that varies continuously (i.e. sound
waves). Analog signals have a frequency and
bandwidth measured in hertz (Hz).
ANSI: (American National Standards Institute).
Armor: A protective covering of steel wires or tape
over the sheath of a telephone cable to prevent
damage during its service life.
Asynchronous Transfer Mode (ATM): A high-speed,
packet-switching technology used to transmit video,
data, voice, etc. via fixed-length cells of 53 bytes.
Attenuation: Loss of signal power between two
points. Attenuation is a ratio of input power vs.
output power, measured in decibels per unit length,
usually dB/km. The received signal is lower in signal
power than the transmitted signal.
Backbone: The facility, such as cables and
connectors, that connects equipment rooms,
telecommunications closets and entrance
facilities. Can be inter-building or intra-building.
Bandwidth: A measure of capacity of
communications media. Greater bandwidth allows
communication of more information in a given period
of time. Bandwidth is generally described either
in terms of analog signals in units of Hertz (Hz),
which describes the maximum number of cycles per
second, or in terms of digital signals in units of bits
per second.
BER (Bit-Error Rate): The ratio of incorrectly
transmitted bits to correctly transmitted bits.
Binder: A spirally applied colored thread or plastic
ribbon used to separate and identify units and groups
of cable pairs by means of color coding.
B-ISDN (Broadband Integrated Digital Network): A
digital network with ATM switching operating at data
rates in excess of 1.544 or 2.048 Mbps. ATM enables
transport and switching of voice, data, image and
video over the same infrastructure.
Broadband: An adjective used to describe large-
capacity networks that are able to carry several
services at the same time, such as data, voice
and video.
Byte: Eight bits of digital data.
Cable, Aerial: Cable suspended in the air usually on
utility poles. Except for self supporting cables
an external messenger strand is used to support
the cable.
Cable, Armored: A cable having an outer protection
usually in the form of a steel corrugated tape.
Cable, Buried: A cable that is buried directly in the
ground without being placed in underground conduit.
Generally waterproof type cables are employed.
Cable, Plastic Insulated (PIC): Cable in which the
conductors are insulated with plastic. Common
insulation is polyethylene and polypropylene.
Although a plastic, PVC insulated conductors are not
referred to as PIC.
Cable, Waterproof: Cable containing a waterproof
filling compound that fills all available space in the
core and between core tape and shield and thus
preventing the entrance of water.
Cable, Drop Wire: One or more pairs of insulated
wires used to run a subscriber's line from the
distribution terminal at a pole to the protector on the
subscriber's premises.
Cable, Figure 8: Cables designed for self supporting
aerial installations. The multi-pair core and steel
support messenger are integrated in a parallel
configuration to enable simultaneous installation of
cable and messenger.
Capacitance: The ability of a dielectric material
between conductors to store electrical energy
when a difference of potential exists between the
conductors. The unit of measurement is the farad,
which is the capacitance value that will store a
charge of one coulomb when a one volt potential
difference exists between the conductors
Capacitance, Mutual: One of the primary
constants of a cable pair which contributes to
transmission loss.
Capacitance, Unbalance To Ground: The inequality
between the grounded capacitance of a wire and its
mate of a pair which causes pickup of energy from
external sources, usually power transmission lines
CATV: (Community Antenna Television)
CCTV: (Closed-circuit Television)
Central Office: A building housing the telephone
switching apparatus and transmission equipment.
Characteristic Impedance: In a transmission line of
infinite length, the ratio of the applied voltage to the
resultant current at the point the voltage is applied.
Or the impedance which makes a transmission cable
seem infinitely long, when connected across the
cable’s output terminals.
CLEC (Competitive Local Exchange Carrier):
An American term for a telephone company that was
created after the Telecommunications Act of 1996
made it legal for companies to compete with the
ILECs. Contrast with ILEC.
Closure, Cable: Any of several types of housings
that can be used to enclose cable sheath openings
necessary for splicing or terminating.
CO (Central Office): A telephone company facility
that handles the switching of telephone calls on the
public switched telephone network (PSTN) for a
small regional area.
Coaxial Capacitance: The capacitance of a single
insulated conductor completely surrounded by a
dielectric medium.
Conductor: A material that offers low resistance
to the flow of electrical current.
Core Network: Combination of telephone switching
offices and transmission plant connecting switching
offices together. In the United States, local exchange
core networks are linked by several competing inter-
exchange networks; in the rest of the world (ROW)
the Core Network extends to national boundaries.
Crosstalk: The transmitted signal on one circuit or
cable pair causes interference in another circuit or
cable pair.
Crosstalk, Far-End: Crosstalk measured by applying
the disturbing signal on one pair at the near end and
measuring the pick up on the disturbed pair at the
far end.
Crosstalk, Near-End: Crosstalk measured by applying
and measuring the disturbing signal on two pairs at
the same end.
Data Link: The cable, receiver and transmitter that
connect two points communicating with digital data.
Decibel (dB): The unit used to describe relative gain
or loss of signal power, generally per unit length.
Abbreviated dB, the decibel is a ratio of power out
vs. power in. Increases or reductions of 3 dB will
result in doubling or halving, respectively, the power
in a circuit.
Delay Skew: The propagation delay difference
between the slowest and fastest cable pair.
Digital: Encoded as a discrete signal in binary ones
and zeros.
Digital Signal: A signal that takes on only two values,
off or on, typically represented by “0” or “1”. Digital
signals require less power but (typically) more
bandwidth than analog and copies of digital signals
can be made exactly like the original.
DLC (Digital Loop Carrier): A digital transmission
system designed for a telephony subscriber’s loop
plant. It multiplexes multiple circuits onto very few
wires or onto a single fiber pair.
DS1 (Digital Signal 1): Twenty-four voice channels
packed into a 193-bit frame and transmitted at
1.544 Mbps. The unframed version, or payload,
is 192 bits at a rate of 1.536 Mbps.
DS1C: Two T2 frames packed into a higher-level
frame transmitted at 3.15 Mbps.
DS2 (Digital Signal 2): Four T1 frames packed into
a higher-level frame transmitted at 6.312 Mbps.