|
| O |
|
|
O
|
Orange |
OC-n
|
See
Optical Carrier n |
Octet
|
8
bits (also called a byte). |
OFSTP
|
Optical
Fiber Standard Test Procedure. |
Ohm
|
The
electrical unit of resistance. The value of resistance through which
a potential of one volt will maintain a current of one ampere. |
Ohm's
Law
|
Stated
E=IR, I=E/R, or R=E/I, the current "I" in a circuit is directly
proportional to the voltage "E", and inversely proportional
to the resistance "R". |
Optical
Carrier n
|
Optical
signal standards. The "n" indicates the level where the
respective data rate is exactly "n" times the first level
OC-1. OC-1 has a data rate of 51.84 Mbps. OC-3 is 3 times that rate
or 155.52 Mbps, etc. Associated with SONET. |
OLTS
|
Optical
Loss Test Set |
Open
|
A
break in the continuity of a circuit. |
Optical
Fiber
|
A
thin glass or plastic filament used for the transmission of information
via light signals. The signal carrying part of a fiber optic cable. |
Optical
Fiber Cable
|
An
assembly consisting of one or more optical fibers. |
Optical
Fiber Duplex Adapter
|
A
mechanical media termination device designed to align and join two
duplex connectors. |
Optical
Fiber Duplex Connection
|
A
mated assembly of two duplex connectors and a duplex adapter. |
Optical
Fiber Duplex Connector
|
A
mechanical media termination device designed to transfer optical power
between two pairs of optical fibers. |
Optical
Time Domain Reflectometry.
|
A
method for evaluating optical fiber based on detecting and measuring
backscattered (reflected) light. Used to measure fiber length and
attenuation, evaluate splice and connector joints, locate faults,
and certify cabling systems. |
OSI
|
Open
Systems Interconnection |
Outside
Plant
|
Cabling,
equipment, or structures that are out of doors. |
OTDR
|
Optical
Time Domain Reflectometry. |
Outlet
|
A
connecting device in the work area on which a horizontal cable terminates. |
Outlet
Box
|
A
metallic or non-metallic box mounted within a wall, floor, or ceiling
used to hold outlet, connector, or transition devices. |
Output
|
The useful signal
or power delivered by a circuit or device.
Top
|
|
| P |
|
|
PABX
|
Private Automatic
Branch Exchange |
Packet
|
Bits grouped serially
in a defined format, containing a command or data message sent over
a network. |
PAM5x5
|
Signal encoding
scheme used in the Ethernet 100Base-T2 and 1000Base-T media systems. |
Patch
Cable, Patch Cord
|
A flexible piece
of cable terminated at both ends with connectors. Used for interconnecting
circuits on a patch panel or cross connect. |
Patch
Panel
|
A passive device,
typically flat plate holding feed through connectors, to allow circuit
arrangements and rearrangements by simply plugging and unplugging
patch cables. |
Pathway
|
A facility for
the placement of telecommunication or networking cables. |
PBX
|
Private Branch
Exchange |
PC
|
Personal Computer |
PCC
|
Premises Communication
Cable, CSA Cable Designation. |
PDN
|
Public Data Network |
Peak
|
The maximum instantaneous
value of a varying current or voltage. |
Pedestal
|
A device, usually
mounted on the floor, which is used to house voice/data jacks or power
outlets at the point of use. Also referred to as a monument, tombstone,
above floor fitting or doghouse. |
Periodicity
|
Uniformly spaced
variations in the insulation diameter of a transmission cable that
result in reflections of a signal. |
Phase
|
An angular relationship
between waves. |
Phase
Modulation (PM)
|
One of three basic
methods (see also Amplitude and Frequency Modulation) of adding information
to a sine wave signal in which its phase is varied to impose information
on it. |
Phase
Shift
|
A change in the
phase relationship between two alternating quantities. |
Photo
detector
|
Used on the receiving
end of a fiber optic cable to convert light energy into electrical
energy. |
PHY
|
Physical Layer
device. |
Physical
Layer
|
Layer one of the
seven layer ISO Reference Model for Open Systems Interconnection.
The physical layer is responsible for the transmission of signals,
such as electrical signals, optical signals, or radio signals, between
computing machines. |
Pico
|
Prefix meaning
one millionth of one millionth. |
Pico
farad
|
One millionth of
one millionth of a farad. Abbreviated "pf". |
Pin-diode
|
A photo detector
used to convert optical signals to electrical signals in a receiver. |
Plastic
|
High polymeric
substances, including both natural and synthetic products, but excluding
the rubbers that are capable of flowing under heat and pressure. |
Plastic
Fiber
|
An optical fiber
made of plastic rather than glass. |
Plasticizer
|
A chemical added
to plastics to make them softer and more flexible. |
Plenum
|
The air handling
space between the walls, under structural floors, and above drop ceilings
used to circulate and otherwise handle air in a building. Such spaces
are considered plenums only if they are used for air handling. Work
spaces are generally not considered plenums. |
Plenum
Cable
|
A cable that is
rated as having adequate fire resistance and low smoke producing characteristics
for use in air handling spaces (plenum). |
Plug
|
A male connector. |
PMD
|
Physical Media
Dependent |
POF
|
Plastic Optical
Fiber. |
Polybutadiene
|
A type of synthetic
rubber often blended with other synthetic rubbers to improve their
properties. |
Polyethylene
|
A thermoplastic
material having excellent electrical properties. |
Polymer
|
A substance made
of repeating chemical units or molecules. The term is often used in
place of plastic, rubber, or elastomer. |
Polypropylene
|
A thermoplastic
material similar to polyethylene but somewhat stiffer and with a higher
softening point (temperature). |
Polyurethane
|
Broad class of
thermoplastic polymers with good abrasion and solvent resistance.
Can be solid or cellular (foam). |
Polyvinyl
Chloride (PVC)
|
A general purpose
thermoplastic used for wire and cable insulation and plastics. PVC
is know for high flexibility. Often used in nonplenum wire insulation
and cable jackets. A modified version of the material may be found
in jacketing of some plenum rated cables. |
POTS
|
Plain Old Telephone
System |
Potting
|
Sealing by filling
with a substance to exclude moisture. |
Power
Level
|
The difference
between the total power delivered to a circuit, cable, or device and
the power delivered by that device to a load. |
Power
Ratio
|
The ratio of power
appearing at the load to the input power. Expressed in dB. |
Premise
Cabling
|
The entire cabling
system on the user's premises used for transmission of voice, data,
video and power. |
Prewiring
|
Wiring installed
before walls and ceilings are enclosed. |
Private
Branch Exchange (PBX)
|
A private telephone
switching system, usually located on a customer's premises connecting
a common group of lines from one or more central offices to provide
service to a number of individual phones. Now used interchangeably
with PABX (Private Automatic Branch Exchange). |
Propagation
Delay
|
Time required for
a signal to pass from the input to the output of a device. |
Protector
|
A device that limits
damaging voltages on metallic conductors. |
Protocol
|
A set of agree-upon
rules and message formats for exchanging information among devices
on a network. |
PSELFEXT
|
Power Sum Equal
Level Far End Crosstalk |
PSNEXT
|
Power Sum Near
End Crosstalk |
Public
Data Network
|
A network established
and operated for the specific purpose of Providing data transmission
services to the public. |
Public
Switched Network
|
Any common carrier
network that provides circuit switching between public users, such
as the public telephone network, telex or MCI's Execunet. |
Pull
Strength, Pull Tension
|
The pulling force
that can be applied to a cable without affecting the specified characteristics
of the cable. |
Pulse
|
A current or voltage
which changes abruptly from one value to another and back to the original
value in a finite length of time. |
Pulse
Code Modulation (PCM)
|
The most common
method of representing an analog signal, such as speech, by sampling
at a regular rate and converting each sample to an equivalent digital
code. |
PVC
|
Polyvinyl Chloride |
PVDF
|
Polyvinylidene
Fluoride
|
|
| Q |
|
|
Quartet
Signaling
|
The signaling
method used by 100VG-AnyLAN, in which the 100 Mbps signal is divided
into four 25 Mbps channels and then transmitted over different pairs
of a cable. Category 3 cables transmit one channel on each of four
pairs.
Top
|
|
| R |
|
|
R
|
Symbol
for Resistance |
Raceway
|
Any
channel designated for holding wires or cables. Raceways may be metallic
or nonmetallic and may totally or partially enclose the wiring. (e.g.
conduit, cable trough, cellular floor, electrical metallic tubing,
sleeves, slots, under floor raceways, surface raceways, lighting fixture
raceways, wire ways, bus ways, auxiliary gutters, and ventilated flexible
cableways) |
Radio
Frequency
|
The
frequencies in the electromagnetic spectrum that are used for radio
communications. |
RBOC
|
Regional
Bell Operating Company. One of the seven Bell operating companies
that were formed during the divestiture of AT&T. |
RCDD
|
Registered
Communication Distribution Designer. A certification of BICSI, an
industry organization, for individuals qualified to consult and design
telecommunications distribution systems. |
Reactance
|
A
measure of the combined effects of capacitance and inductance on an
alternating current. The amount of such opposition varies with the
frequency of the current. The reactance of a capacitor decreases with
an increase in frequency. The opposite occurs with an inductance. |
Receiver
|
A
device whose purpose is to capture transmitted signal energy and convert
that energy for useful functions. In fiber optic systems, an electronic
component that converts light energy to electrical energy. |
Reflection
|
A
return of electromagnetic energy that occurs at an impedance mismatch
in a transmission line, such as a LAN cable. |
Refractive
Index.
|
The
ratio of the speed of light in a vacuum to its velocity in a transmitting
medium, such as an optical fiber core. |
Repeater
|
A
device that receives, amplifies (and sometimes reshapes), and retransmits
a signal. It is used to boost signal levels and extend the distance
a signal can be transmitted. It can physically extend the distance
of a LAN or connect two LAN segments. |
Resistance
|
In
dc circuits, the opposition a material offers to current flow, measured
in ohms. In ac circuits, resistance is the real component of impedance
and may be higher than the value measured at dc. |
Resonance
|
An
ac circuit condition in which inductive and capacitive interact to
cause a minimum or maximum circuit impedance. |
Retractile
Cord
|
A
cord having specially treated insulation or jacket so that it will
retract like a spring. Retractibility may be added to all or part
of a cord's length. |
Reversed
Pair
|
A
wiring error in twisted pair cabling where the conductors of a pair
are reversed between connector pins at each end of a cable. |
RF
|
see
Radio Frequency |
RFI
|
Radio
Frequency Interference. Electromagnetic interference at radio frequencies. |
RFP
|
Request
for Proposal |
RFQ
|
Request
for Quote (or Quotation) |
RG/U
|
Radio
Grade/Universal. RG is the common military designation for coaxial
cable. |
Ring
|
1.
A polarity designation of one wire of a pair indicating that the wire
is that of the secondary color of a 5-pair group (e.g. the blue white
wire of the blue pair). 2. A wiring contact to which the ring wire
is attached. 3. The negative wiring polarity (see Tip). |
Ring
Network
|
A
network topology in which terminals are connected in a point-to-point
serial fashion in an unbroken circular configuration. Many logical
rings are wired as a star for greater reliability. |
Ripcord
|
A
cord placed directly under the jacket of a cable in order to facilitate
stripping (removal) of the jacket. |
Riser
|
The
conduit or path between floors of a building into which telephone,
networking, and other utility cables are placed to bring service from
one floor to another. |
Riser
Cable
|
A
type of cable used in vertical building shafts, such as telecommunications
and utility shafts. Riser cable typically has more mechanical strength
than general use cable and has an intermediate fire protection rating. |
RJ
|
A
term from the telephone industry, used for jacks (connectors) that
were registered for use with particular types of telephone services.
RJ stands for "registered jack". |
RJ-45
|
A
USOC code identifying an 8-pin modular plug or jack used with unshielded
twisted pair cable. Officially, an RJ-45 connector is a telephone
connector designed for voice grade circuits only. RJ-45 type connectors
with better signal handling characteristics are called 8-pin connectors
in most standards documents, though most people continue to use the
RJ-45 name for all 8-pin connectors. |
RMS
|
Root
Mean Square. |
Rope
Strand
|
A
conductor composed of groups of twisted strands. |
Rubber
|
A
general term used to describe wire insulations made of thermosetting
elastomers, such as natural or synthetic rubbers, neoprene, Hypalon,
butyl rubber, and others. |
Rx
|
Receive |
RZ
|
Return to Zero
Top
|
|
| S |
|
|
SAS
|
Single
Attachment Station. Term used with FDDI networks to denote a station
that attaches to only one of two rings in a dual ring environment. |
SBR
|
A
copolymer of styrene and butadiene. Also GR-S or Buna-S. Most commonly
used type of synthetic rubber. |
SC
Connector
|
A
fiber optic connector having a 2.5mm ferrule, push-pull latching mechanism,
and the ability to be snapped together to form duplex and multifiber
connectors. SC connectors are the preferred fiber optic cable for
premises cabling, and are recommended by the TIA/EIA-568-A Standard
for structured cabling. Used with Ethernet 100Base-FX and 1000Base-LX/SX
fiber optic media systems. |
Scanner
|
A
cable testing device which uses TDR methods to detect cable transmission
anomalies and error conditions. |
Screen
|
see
Shield |
Screened
Twisted Pair (ScTP) cable
|
Four
pair UTP, with a single foil or braided screen surrounding all four
pairs in order to minimize EMI radiation or susceptibility. Screened
twisted pair is sometimes called Foil Twisted Pair (FTP). ScTP can
be thought of as a shielded version of the Category 3, 4, & 5
UTP cables. |
Screened/Shielded
Twisted Pair (SSTP)
|
Four
pair cabling, with each pair having its own individual Shield, in
addition to an overall shield surrounding all four pairs. SSTP offers
similar performance to Type 1 STP except with 4 pairs (rather than
2) and in a 100 ohm impedance (rather than 150). |
ScTP
|
see
Screened Twisted Pair cable |
SDH
|
see
Synchronous Digital Hierarchy. |
Segment
|
On
Ethernet a media segment may be made up of one or more cable sections
joined together to produce a continuous cable for carrying Ethernet
signals. |
Semiconductor
|
In
wire industry terminology, a material possessing electrical conductivity
that falls somewhere between that of conductors and insulators. Usually
made by adding carbon particles to an insulator. Not the same as semiconductor
materials such as silicon, germanium, etc. |
Separator
|
Pertaining
to wire and cable, a layer of insulating material such as textile,
paper, Mylar, etc. which is placed between a conductor and its dielectric,
between a cable jacket and the components it covers, or between various
components of a multiple conductor cable. It can be utilized to improve
stripping qualities, flexibility, or can offer additional mechanical
or electrical protection to the components it separates. |
Sheath
|
see
Jacket |
Shield
|
A
metallic foil or multiwire screen mesh that is used to prevent electromagnetic
fields from penetrating or exiting a transmission cable. Also referred
to as a "screen". |
Shield
Coverage
|
The
physical area of a cable that is actually covered by shielding material,
often expressed as a percentage. |
Shield
Effectiveness
|
The
relative ability of a shield to screen out undesirable interference.
Frequently confused with the term shield coverage. |
Shielded
Twisted Pair (STP)
|
A
type of twisted pair cable in which the pairs are enclosed in an outer
braided shield, although individual pairs may also be shielded. STP
most often refers to the 150 ohm IBM Type 1, 2, 6, 8, & 9 cables
used with Token Ring networks. |
Signal
|
The
information conveyed through a communication system. |
Signal
to noise ratio
|
The
ratio of received signal level to received noise level, expressed
in dB. Abbreviated S/N. A higher S/N ratio indicates better channel
performance. |
Silicone
|
General
Electric trademark for a material made from silicone and oxygen. Can
be in thermosetting elastomer or liquid form. The thermosetting elastomer
form is noted for high heat resistance. |
Silver
Satin
|
The
name for the silver-gray voice-grade patch cable used to connect a
telephone to a wall jacket. Typical silver satin patch cables do not
have twisted pair wires, which makes them unsuitable for use in LAN
applications. The lack of twisted pairs will result in high levels
of crosstalk. |
Simplex
Transmission
|
Data
transmission over a circuit capable of transmitting in one preassigned
direction only. |
Single
Mode Fiber
|
An
optical fiber that will allow only one mode to propagate. The fiber
has a very small core diameter of approximately 8 µm. It permits signal
transmission at extremely high bandwidth and allows very long transmission
distances. |
Single-ended
|
An
unbalanced circuit or transmission line, such as a coaxial cable transmission
line (see also Balanced Line). |
Sinusoidal
|
A
signal which varies over time in proportion to the sine of an angle.
Ordinary alternating current is sinusoidal. |
Skew
Rays
|
A
ray that does not intersect the fiber axis. Generally, a light ray
that enters the fiber at a very high angle. |
Skin
Effect
|
The
tendency of alternating current to travel on the surface of a conductor
as the frequency increases. |
SMA
Connector
|
A
threaded type fiber optic connector. The 905 version is a straight
ferrule design, whereas the 906 is a stepped ferrule design. |
SMF
|
see
Single Mode Fiber |
S/N
|
see
Signal to noise ratio |
SNR
|
see
Signal to noise ratio |
SONET
|
see
Synchronous Optical Network. |
Source
|
In
fiber optics, the device which converts the electrical information
carrying signal to an optical signal for transmission over an optical
fiber. A fiber-optic source may be a light emitting diode or laser
diode. |
Spectral
Bandwidth
|
The
difference between wavelengths at which the radiant intensity of illumination
is half its peak intensity. |
Spectrum
|
Frequencies
that exist in a continuous range and have a common characteristic.
A spectrum may be inclusive of many spectrums (e.g. the electromagnetic
radiation spectrum includes the light spectrum, radio spectrum, infrared
spectrum, etc.) |
Speed
of Light (c)
|
In
a vacuum, 299,800,000 meters per second. |
Splice
|
A
joining of conductors generally from separate sheaths. |
Splice
Closure
|
A
device used to protect a cable or wire splice. |
Split
Pair
|
A
wiring error in twisted pair cabling where one of a pair's wires is
interchanged with one of another pair's wires. Split pair conditions
may be determined with a transmission test. Simple DC continuity testing
will not reveal the error, because the correct pin-to-pin continuity
exists between ends. However, the error may result in impedance mismatch,
excessive crosstalk, susceptibility to interference, and signal radiation. |
SRL
|
see
Structural Return Loss |
SSTP,
S/STP
|
see
Screened/Shielded Twisted Pair |
ST
Connector
|
Designation
for the "straight tip" connector developed by AT&T.
This fiber optic connector features a physically contacting non-rotating
2.5mm ferrule design and bayonet connector-to-adapter mating. Used
with Ethernet 10Base-FL and FOIRL links. |
Standing
Wave
|
The
stationary pattern of waves produced by two waves of the same frequency
traveling in opposite directions on the same transmission line. The
existence of voltage and current maxima and minima along a transmission
line is a result of reflected energy from an impedance mismatch. |
Standing
Wave Ratio (swr)
|
A
ratio of the maximum amplitude to the minimum amplitude of a standing
wave stated in current or voltage amplitudes. |
Star
Network
|
A
network in which all stations are connected through a single point. |
Star
Topology
|
A
topology in which each outlet/connector is wired directly to the distribution
device. |
Static
Charge
|
An
electrical charge that is bound to an object. An unmoving electrical
charge. |
Station
|
A
unique, addressable device on a network. |
Stay
Cord
|
A
component of a cable, usually of high tensile strength, used to anchor
the cable ends at their points of termination and keep any pull on
the cable from being transferred to the electrical conductors. |
Step
Index Fiber
|
An
optical fiber in which the core is of uniform refractive index with
a sharp decrease in the index of refraction at the core-cladding interface.
Step index multimode fibers generally have lower bandwidths than graded
index multimode fibers. |
Step
Insulated
|
Process
of applying insulation in two layers. Typically used in shielded networking
cables such that the outer layer of insulation can be removed and
remaining conductor and insulation can be terminated in a RJ-45 type
connector. |
Stitching
|
The
activity of terminating multiconductor cables on a punch down block. |
STP
|
see
Shielded Twisted Pair |
STP-A
|
Refers
to the enhanced IBM Cabling System specifications with the Type "A"
suffix. The original IBM Type 1, 2, 6, & 9 specifications were
designed to support operation of 4 and 16 Mbps Token-Ring. The enhanced
Type 1A, 2A, 6A, & 9A cable specifications were designed to support
operation of 100 Mbps FDDI signals over copper. |
Strain
Gauge
|
A
device for determining the amount of strain (change in dimensions)
when a stress is applied. |
Strength
Member
|
That
part of a fiber optic cable that increases the cable's tensile strength
and serves as a load bearing component. Usually made of Kevlar aramid
yarn, fiberglass filaments, or steel strands. |
Structural
Return Loss (SRL)
|
A
measure of the impedance uniformity of a cable. It measures energy
reflected due to structural variations in the cable. A higher SRL
number indicates better performance (more uniformity and lower reflections). |
Structured
Wiring
|
Telecommunications
cabling that is organized into a hierarchy of wiring termination and
interconnection structures. The concept of structured wiring is used
in the common standards from the TIA and EIA. |
STS-n
|
Synchronous
Transport Signal-n (see Optical Carrier-n). |
Subminiature
D Connector
|
A
family of multipin data connectors available in 9, 15, 25 and 37 pin
configurations. Sometimes referred to as DB9, DB15, DB25 and DB37
connectors respectively. |
Surge
|
A
temporary and relatively large increase in the voltage or current
in an electric circuit or cable. Also called transient. |
Surge
Suppression
|
The
process by which transient voltage surges are prevented from reaching
sensitive electronic equipment. |
Sweep
Test
|
Pertaining
to cable, the frequency response is verified by generating an RF voltage
whose frequency is swept repeatedly through a given frequency range
at a rapid constant range. The cable response is observed on an oscilloscope.
The structural return loss sweep test measures the magnitude of internal
cable reflections. A high structural return loss is desirable. |
Synchronous
|
Transmission
in which the data character and bits are transmitted at a fixed rate
with the transmitter and receiver being synchronized. |
Synchronous
Digital Hierarchy (SDH)
|
International
standard for optical digital transmission at hierarchical rates from
155 Mbps to 2.5 Gbps and beyond. |
Synchronous
Optical Network (SONET)
|
A USA standard
for optical digital transmission at hierarchical rates from 155
Mbps to 2.5 Gbps and beyond.
Top
|
|
| T |
|
|
T1
|
T1
is a 1.544 Mbps multichannel digital transmission system for voice
or data provided by long distance carriers. Also referred to as DS1
(Data Services). |
T3
|
T3
is a 44.736 Mbps multichannel digital transmission system for voice
or data provided by long distance carriers. Also referred to as DS3
(Data Services). |
Tap
|
On
Ethernet 10Base5 thick coaxial cable, a tap is a method of connecting
a transceiver to the cable by drilling a hole in the cable, inserting
a contact to the center conductor, and clamping the transceiver onto
the cable at the tap. |
TC
|
Telecommunications
Cross Connect. |
TDR
|
See
Time Domain Reflectometry |
Teflon
|
Dupont
Company trademark for fluorocarbon resins (see FEP and TFE). |
Telecommunications
Closet
|
see
Closet |
Telecommunications
Equipment Room
|
see
Equipment Room |
Terminal
|
1.
A point at which information may enter or leave a communications network.
2. A device by means of which wires may be connected to each other. |
Terminator
|
A
device that provides electrical resistance at the end of a transmission
line. Its function is to absorb signals on the line, thereby keeping
them from bouncing back and being received again by the network. |
TFE
|
Tetraflouroethylene.
A thermoplastic material with good electrical insulating properties
and chemical and heat resistance. |
Thermal
Rating
|
The
temperature range in which a material will perform its function without
undue degradation. |
Thermoplastic
|
A
material which will soften, flow, or distort appreciably when subjected
to sufficient heat and pressure. Examples are polyvinyl chloride and
polyethylene. |
Thermosetting
|
A
material which will not soften, flow, or distort appreciably when
subjected to sufficient head and pressure. Examples are rubber and
neoprene. |
Thicknet
|
Ethernet
10Base5 coaxial cable. |
Thinnet
|
Ethernet
10Base2 coaxial cable. Also called "Cheapernet". |
TIA
|
Telecommunications
Industry Association. Body which authored the TIA/EIA 568-A "Commercial
Building Telecommunications Wiring Standard" in conjunction with
EIA. |
Time
Division Multiplexing (TDM)
|
A
technique for combining many signals on a single circuit by interleaving
bits or bytes of data from successive channels. |
Time
Domain Reflectometry
|
A
technique for measuring cable lengths by timing the period between
a test pulse and the reflection of the pulse from an impedance discontinuity
on the cable. The returned waveform reveals many undesired cable conditions,
including shorts, opens, and transmission anomalies due to excessive
bends or crushing. The length to any anomaly, including the unterminated
cable end, may be computed from the relative time of the wave return
and nominal velocity of propagation of the pulse through the cable.
See also Optical Time Domain Reflectometry. |
Tinsel
|
A
type of electrical conductor comprised of a number of tiny threads,
each having a fine, flat ribbon of copper or other metal closely spiraled
about it. Used for small size cables requiring limpness and extra-long
flex life. |
Tip
|
1.
A polarity designation of one wire of a pair indicating that the wire
is that of the primary (common) color of a 5-pair group (e.g. the
white-blue wire of the blue pair). 2. A wiring contact to which the
tip wire is connected. 3. The positive wiring polarity (also see "ring"). |
TNC
|
A
threaded connector used to terminate coaxial cables. TNC is an acronym
for threaded Neill-Concelman. |
Token
Passing
|
A
network access method in which a station must wait to receive a special
token frame before transmitting. |
Token-Ring
|
A
local area network (LAN) protocol defined in the IEEE 802.5 standard
in which computers access the network through a token passing scheme.
Uses a star-wired ring topology. |
Topology
|
The
physical or logical interconnection pattern of a network. |
Transceiver
|
A
combination of the words Transmitter and receiver. A transceiver is
the set of electronics that send and receive signals on the Ethernet
media system. Transceivers may be small outboard devices, or may be
built into an Ethernet port. Also called Media Attachment Unit, or
MAU. |
Tracer
|
The
contrasting color coding stripe along an insulated conductor of a
wire pair. |
Transducer
|
A
device for converting mechanical energy into electrical energy. |
Transfer
Impedance
|
For
a specified cable length, transfer impedance relates to a current
on one surface of a shield to the voltage drop generated by this current
on the opposite surface of the shield. Transfer impedance is used
to determine shield effectiveness against both ingress and egress
of interfering signals. Shields with lower transfer impedance are
more effective than shields with higher transfer impedance. |
Transmission
Line
|
An
arrangement of two or more conductors or a wave guide used to transfer
a signal from one location to another. |
Transmission
Media
|
Anything
such as wire, coaxial cable, fiber optics, air or vacuum, that is
used to carry a signal. |
Transmitter
|
A
device that converts electrical signals for transmission to a distant
point. In fiber optic systems, the electronic component that converts
electrical energy to light energy. |
Transition
Point
|
A
location in the horizontal cabling where flat under carpet cable connects
to round cable. |
Tree
Topology
|
LAN
topology similar to linear bus topology, except that tree networks
can contain branches with multiple nodes. |
Triaxial
Cable, Triax
|
Triax
cable is coax cable with an additional outer copper braid insulated
from signal carrying conductors. It has a core conductor and two concentric
conductive shields. |
Triboelectric
Noise
|
Noise
generated in a shielded cable due to variations in capacitance between
the shield and conductor as the cable is flexed. |
Trunk
Cable
|
see
Feeder Cable. |
TSB
|
Telecommunications
Systems Bulletin |
Turn-key
|
A
contractual arrangement in which one party designs and installs a
system and "turns over the keys" to another party who will
operate the system. |
Twin
axial Cable, Twinax
|
A
type of communication transmission cable consisting of two center
conductors surrounded by an insulating spacer which in turn is surrounded
by a tubular outer conductor (usually a braid, foil or both). The
entire assembly is then covered with an insulating and protective
outer layer. It is similar to coaxial cable except that there are
two conductors at the center. |
Twin-lead
|
A
transmission line having two parallel conductors separated by insulating
material. Line impedance is determined by the diameter and spacing
of the conductors and the insulating material and is usually 300 ohms
for television receiving antennas. |
Twisted
Pair
|
A
multiple conductor cable whose component wires are paired together,
twisted, and enclosed in a single jacket. Each pair consists of two
insulated copper wires twisted together. When driven as a balanced
line, the twisting reduces the susceptibility to external interference
and the radiation of signal energy. Most twisted-pair cabling contains
either 2, 4, or 25 pairs of wires. |
Tx
|
Transmit |
Type
N Connector
|
A
threaded barrel constant impedance coaxial connector for large diameter
cable such as Ethernet 10Base5 thicknet cable. |
Type
1
|
150
ohm shielded twisted pair (STP) cabling conforming to the IBM Cabling
System Specifications. Two twisted pairs of 22 AWG solid conductors
for data communications are enclosed in a braided shield covered with
a sheath. Tested for operation up to 16 MHz. Available in plenum,
non-plenum, riser, and outdoor versions. |
Type
1A
|
Enhanced
version of IBM Type 1 cable rated for operation up to 300 Mhz. Meets
electrical specifications for 150 ohm STP-A Cable as documented in
the TIA/EIA 568-A standard. |
Type
2
|
150
ohm shielded twisted pair (STP) cabling conforming to the IBM Cabling
System specifications. Two twisted pairs of 22 AWG solid conductors
for data communications are enclosed in a braided shield. Four additional
pairs of 22 AWG solid conductors for telephones are also included
in the cable jacket but outside the braided shield. Tested for operation
up to 16 MHz. Available in plenum and non-plenum versions. |
Type
2A
|
Enhanced
version of IBM Type 2 cable rated for operation up to 300 Mhz. Meets
electrical specifications for 150 ohm STP-A Cable as documented in
the TIA/EIA 568-A standard. |
Type
3
|
IBM
Cabling System designation for 100 ohm unshielded twisted pair (UTP)
cabling similar to TIA/EIA Category 3 cabling. 22 AWG or 24 AWG conductors
with a minimum of two twists per linear foot. Typically four twisted
pairs enclosed within cable jacket. |
Type
5
|
100/140
micron optical fiber cable conforming to the IBM Cabling System specifications.
Two optical fibers are surrounded by strength members and a polyurethane
jacket. Type 5J is a 50/125 micron version defined for use in Japan. |
Type
6
|
150
ohm shielded twisted pair (STP) cabling conforming to the IBM Cabling
System specifications. Two twisted pairs of 26 AWG stranded conductors
for data communications. Flexible for use in making patch cables.
Tested for operation up to 16 MHz. Available in non-plenum version
only. |
Type
6A
|
Enhanced
version of IBM Type 6 cable rated for operation up to 300 Mhz. Meets
electrical specifications for 150 ohm STP-A Cable as documented in
the TIA/EIA 568-A standard. |
Type
8
|
150
ohm under-carpet cable conforming to the IBM Cabling System Specifications.
Two individually shielded parallel pairs of 26 AWG solid conductors
for data communications. The cable includes "ramped wings"
to minimize visibility when installed under carpeting. Tested for
operation up to 16 MHz. |
Type
9
|
150
ohm shielded twisted pair (STP) cabling conforming to the IBM Cabling
System Specifications. A plenum rated cable with two twisted pairs
of 26 AWG solid or stranded conductors for data communications enclosed
in a braided shield covered with a sheath. Tested for operation up
to 16 MHz. |
Type
9A
|
Enhanced version
of IBM Type 9 cable rated for operation up to 300 Mhz. Meets electrical
specifications for 150 ohm STP-A Cable as documented in the TIA/EIA
568-A standard.
Top
|
|
| U |
|
|
UL
|
Underwriters
Laboratories, Inc. |
Unbalanced
Line
|
A
transmission line in which voltages on the two conductors are unequal
with respect to ground. Generally one of the conductors is connected
to a ground point. An example of an unbalanced line is a coaxial cable. |
Underground
Cable
|
Cable
that is intended to be placed beneath the surface of the ground in
ducts or conduit. Not necessarily intended for direct burial in the
ground. |
Unilay
|
A
conductor with more than one layer of helically laid wires with the
direction of lay and length of lay the same for all layers. |
Unshielded
Twisted Pair (UTP)
|
Twisted
pair cabling that includes no shielding. UTP most often refers to
the 100 ohm Category 3, 4, & 5 cables specified in the TIA/EIA
568-A standard. |
USOC
|
Universal
Service Order Code. Pronounced "U-Sock". An old Bell System
term used to identify a particular service or device offered under
tariff. Often used to refer to an old cable color code scheme that
was current when USOC codes were in use. |
UTP
|
see Unshielded
Twisted Pair.
Top
|
|
| V |
|
|
V
|
Symbol
for Volt. |
VA
|
Volt-ampere.
A designation of power in terms of voltage and current. |
Vampire
Tap
|
see
Tap |
Velocity
of Propagation
|
The
transmission speed of electrical energy in a length of cable compared
to speed in free space. Usually expressed as a percentage. Test devices
use velocity of propagation to measure a signal's transit time and
thereby calculate the cable's length. |
VGM
|
Voice
Grade Media (see Voice Grade) |
VHF
|
Very
high frequency. The portion of the electromagnetic spectrum extending
from 30 to 300 MHz. |
Video
|
A
signal which contains visual information, such as a picture in a television
system. |
Voice
Grade
|
A
term used for twisted-pair cable used in telephone systems to carry
voice signals. |
Volt
|
The
unit of electrical potential. One volt is the electrical potential
that will cause one ampere of current to flow through one ohm of resistance. |
Voltage
|
Electrical
potential expressed in Volts. |
Voltage
Drop
|
The voltage
developed across a component by the current flow through the resistance
of the component.
Top
|
|
| W |
|
|
W
|
Symbol
for Watt or Wattage |
W
|
White |
Watt
|
A
unit of electrical power. One watt is equivalent to the power represented
by one ampere of current flowing through a load with a voltage drop
of one volt in a dc circuit. |
Wave
Form
|
A
graphical representation of the amplitude of a signal over time. |
Wavelength
|
The
distance between successive peaks or nodes of a wave. |
Wavelength
Division Multiplexing (WDM)
|
The
process of combining and splitting signals on the basis of difference
in their wavelengths. |
WAN
|
Wide
Area Network. A network connecting computers within very large areas,
such as states, countries, and the world. |
wire
fault
|
An
error condition caused by a break in the wires or a short between
the wires (or shield) in a segment of cable. |
Wiring
Closet
|
see
Closet |
Work
Area
|
That
area of the premises cabling where users are located. The area from
the communications outlet to the equipment connected to the premises
cabling. Loosely, an office, cubicle, and so forth. |
Workgroup
|
A
collection of workstations and servers on a LAN that are designated
to communicate and exchange data with one another. |
Workstation
|
A computer connected
to a network at which users interact with software stored on the
network.
Top
|
|
| X |
|
|
X
|
1. Symbol for
reactance. 2. Symbol for cross-connect.
Top
|
|
| Y |
|
|
|
| Z |
|
|
Z
|
Symbol for impedance.
Top
|
|
| 0-9 |
|
|
1Base5
|
IEEE
802.3 shorthand term for StarLAN at 1Mbps data transfer rate. |
10Base2
|
IEEE
802.3 shorthand term for 10 Mbps Ethernet based on Manchester signal
encoding over thin coaxial cable. Also called "Thinnet"
or "Cheapernet". |
10Base5
|
IEEE
802.3 shorthand term for 10 Mbps Ethernet based on Manchester signal
encoding over thick coaxial cable. Also called "Thicknet". |
10Base-F
|
IEEE
802.3 shorthand term for 10 Mbps Ethernet based on Manchester signal
encoding over fiber optic cable. |
10Base-T
|
IEEE
802.3 shorthand term for 10 Mbps Ethernet based on Manchester signal
encoding over category 3 or better twisted pair cable. |
10Broad36
|
IEEE
802.3 shorthand term for 10 Mbps Ethernet on broadband cable. |
100Base-FX
|
IEEE
802.3 shorthand term for 100 Mbps Fast Ethernet based on 4B/5B signal
encoding over fiber optic cable. |
100Base-T
|
IEEE
802.3 shorthand term for entire 100 Mbps Fast Ethernet system. |
100Base-T2
|
IEEE
802.3 shorthand term for 100 Mbps Fast Ethernet based on PAM5x5 signal
encoding and using two pairs of category 3 twisted pair cable. |
100Base-T4
|
IEEE
802.3 shorthand term for 100 Mbps Fast Ethernet based on 8B6T signal
encoding and using four pairs of category 3 twisted pair cable. |
100Base-TX
|
IEEE
802.3 shorthand term for 100 Mbps Fast Ethernet based on 4B/5B signal
encoding and using two pairs of category 5 twisted pair cable. |
100Base-X
|
IEEE
802.3 shorthand term for any 100 Mbps Fast Ethernet system based on
4B/5B signal encoding. Includes 100Base-TX and 100Base-FX. |
1000Base-CX
|
IEEE
802.3 shorthand term for 1000 Mbps Gigabit Ethernet based on 8B/10B
signaling over copper cable. |
1000Base-LX
|
IEEE
802.3 shorthand term for 1000 Mbps Gigabit Ethernet based on 8B/10B
signaling using long wavelength laser transmitters over fiber optic
cable. |
1000Base-SX
|
IEEE
802.3 shorthand term for 1000 Mbps Gigabit Ethernet based on 8B/10B
signaling using short wavelength laser transmitters over fiber optic
cable. |
1000Base-T
|
IEEE
802.3 shorthand term for 1000 Mbps Gigabit Ethernet over twisted pair
cable. |
1000Base-X
|
IEEE
802.3 shorthand term for any 1000 Mbps Gigabit Ethernet based on 8B/10B
signaling. Includes 1000Base-CX, 1000Base-LX, and 1000Base-SX. |
2B+D
|
Describes
basic ISDN service (2B+D = Two bearer channels and one data channel). |
4B/5B
|
Signal
encoding method used in 100Base-TX/FX Fast Ethernet and and FDDI standards.
4-bit binary values are encoded into 5-bit symbols. |
66-type
Connecting Block
|
Used
by telephone company to terminate twisted pairs. Not recommended for
LAN use. |
8B6T
|
Signal
encoding method used in 100Base-T4 Fast Ethernet standard. |
8B/10B
|
Signal
encoding method used in the 1000Base-X Gigabit Ethernet standards. |
802.1
|
see
IEEE 802.1 |
802.2
|
see
IEEE 802.2 |
802.3
|
see
IEEE 802.3 |
802.5
|
see IEEE 802.5
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