Cabling Dictionary




A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0-9


A

A

Ampere
– A unit of measure of electrical current.

AC

see
Alternating Current.

Acceptance
Angle

The
largest angle that a guided ray of light is accepted by a fiber optic
cable.

Access
Method

The
rules by which a network device gains the rights to transmit a communication
on the network. Common methods include carrier sense multiple access
with collision detection, token passing, and demand priority.

ACR

see
Attenuation Crosstalk Ratio.

Alternating
Current

An
electric current that cyclically reverses the direction of flow. Frequency
is the rate at which a full cycle occurs in one second.

Amplitude

The
maximum value of a varying signal.

Amplitude
Modulation

One
of three basic methods (see also Frequency and Phase Modulation) of
adding information to a sine wave signal in which the magnitude of
the signal is varied to impose information on it.

ANSI

American
National Standards Institute

Analog
Signal

An
electrical signal that varies continuously without having discrete
values (as with a “digital” signal).

AppleTalk

Apple
Computer’s networking scheme, integrated into most Apple system software,
that allows Apple computing systems to participate in peer to peer
computer networks and to also access the services of AppleTalk servers.
See also LocalTalk.

ARCnet

Attached
Resource Computer Network. A relatively low speed form of LAN data
link technology (2.5 Mbps) developed by Datapoint, in which all systems
are attached to a common coaxial cable. ARCnet uses a token-bus form
of medium access control in which a system transmits only when it
has the token

Asynchronous

Transmission
where sending and receiving devices are not synchronized. Data must
carry signals to indicate data division.

Asynchronous
Transfer Mode (ATM)

A
form of very fast packet switching in which data is carried in fixed
length units called “cells”. Each cell is 53 bytes in length,
with 5 bytes used as a header in each cell. ATM employs mechanisms
that can be used to set up virtual circuits between users, in which
a pair of users appear to have a dedicated circuit between them. ATM
is defined in specifications from the ITU and ATM Forum.

Attachment
Unit Interface.

The
IEEE 802.3 standard name for the cable connecting an Ethernet transceiver
(MAU) to a networked device. An AUI cable is equipped with a 15-pin
connector that mates with a 15-pin connector on the networked device.

Attenuation

The
decrease in magnitude of a signal as it travels through any transmission
medium such as a cable or optical fiber. Measured in dB per unit of
length.

Attenuation
Crosstalk Ratio (ACR)

The
difference between attenuation and crosstalk, measured in dB, at a
given frequency. A quality factor for cabling to assure that signal
sent down a twisted pair is stronger at the receiving end of the cable
than any interference imposed on the same pair by crosstalk from other
pairs.

Audio

Used
to describe the range of frequencies within range of human hearing;
approximately 20 to 20,000 Hz.

AUI

see
Attachment Unit Interface.

AWG

American Wire
Gage – A wire diameter specification. The smaller the AWG number,
the larger the wire diameter.

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B

Backbone

A
cable connection between telecommunication or wiring closets, floor
distribution terminals, entrance facilities, and equipment rooms either
within or between buildings. In star networks, the backbone cable
interconnects hubs and similar devices, as opposed to cables running
between hub and station. In a bus network, the bus cable.

Back
reflection

The
light reflected back towards the source from the fiber optic ends
and deformations.

Backscattering

Refers
to light diffraction at microscopic non-uniformities in the index
of refraction of the optical fiber causing back reflection of optical
power towards the source.

Balanced
Cable, Balanced Line

A
cable having two identical conductors that carry voltages of opposite
polarities and equal magnitude with respect to ground. The conductors
are twisted to maintain balance over a distance.

Balanced
Transmission

A
mode of signal transmission in which each conductor carries the signal
of equal magnitude, but opposite polarity. A 5 volt signal for example,
appears as a +2.5 Volts on one conductor and -2.5 Volts on the other.

Balun

An
impedance matching transformer that converts the impedance of one
interface to the impedance of another interface. Generally used to
connect balanced twisted pair cabling with unbalanced coaxial cabling.
The term is derived from “balanced / unbalanced”.

Band
pass

A
range of frequencies or wavelengths within which a component operates.

Baseband

A
transmission method in which the entire bandwidth of the transmission
medium is used to transmit a single digital signal. The signal is
driven directly onto the transmission medium without modulation of
any kind. Baseband is simpler, cheaper and less sophisticated than
Broadband.

Bandwidth

The
range of frequencies required for proper transmission of a signal.
Expressed in Hertz (cycles per second). The higher the bandwidth,
the more information that can be carried. A continuous range starting
from zero is said to be “baseband”, while a range starting
substantially above zero is “broadband”.

Baud

The
number of changes in signal per second. A given baud rate does not
necessarily transmit an equal number of bits/sec. For example, a signal
with four voltage levels may be used to transfer two bits of information
for every baud.

Beacon

A
special frame in Token-Ring systems indicating a serious problem with
the ring such as a break.

BEL

A
unit that represents the logarithm of the ratio of two levels.

Bend
Loss

A
form of increased attenuation in an optical fiber caused by an excessively
small bend radius. The attenuation may be permanent if micro fractures
caused by the bend continue to affect transmission of the light signal.

Bend
Radius

Radius
of curvature that a fiber optic or metallic cable can bend before
the risk of breakage or increased attenuation occurs.

BER

see
Bit Error Rate

BICSI

Building
Industry Consulting Service International.

Binder

A
tape or thread used to hold assembled cable components in place.

BISDN

Broadband
ISDN

Bit

One
binary digit.

Bit
Error Rate

A
measure of data integrity, expressed as the ratio of received bits
that are in error, relative to the amount of bits received. Often
expressed as a negative power of ten.

Bit
Stream

A
continuous transfer of bits over some medium.

Bit
Stuffing

A
method of breaking up continuous strings of 1 bits by inserting a
0 bit. The 0 bit is removed at the receiver.

Bit
Time

The
length of time required to transmit one bit of information.

BL

Blue.

BNC

A
coaxial connector that uses a “bayonet” style turn and lock
mating method. Used with RG-58 or smaller coaxial cable. Used with
10Base2 Ethernet thin coaxial cable. BNC is an acronym for Bayonet-Neill-Concelman.

Bonding

A
method used to produce good electrical contact between metallic parts.
Also refers to the grounding bars and straps used in buildings to
bond equipment to an approved ground.

BPS

Bits
per second.

BR

Brown.

Braid

Fine
wires interwoven to form a tubular flexible structure that may be
applied over one or more wires for the purpose of shielding. May also
be formed into a flattened conductor to be used as a grounding strap.

BRI

ISDN
Basic Rate Interface

Bridged
Tap

Multiple
appearances of the same cable pair at several distribution points.

Broadband

A
transmission facility having a bandwidth sufficient to carry multiple
voice, video or data channels simultaneously. Each channel occupies
(is modulated to) a different frequency bandwidth on the transmission
medium and is demodulated to its original frequency at the receiving
end. Channels are separated by “guard bands” (empty spaces)
to ensure that each channel will not interfere with its neighboring
channels. This technique is used to provide many CATV channels on
one coaxial cable.

Broadcast

Sending
data to more than one receiving device at a time.

Buffer

A
protective coating over a strand of optical fiber.

Bus
Topology

1.
In general, a physical layout of network devices in which all devices
must share a common medium to transfer data, and no two devices may
transmit simultaneously. 2. With LANs, a linear network topology in
which all computers are connected to a single cable.

Butyl
Rubber

A
synthetic rubber with good electrical insulating properties.

Byte

A group of 8
bits.

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C

c

A
small “c” is the symbol for the speed of light in a vacuum.

C

A
capital “C” is the designation for Celsius.

Cable

A
group of insulated conductors enclosed within a common jacket.

Cable
Sheath

A
covering over the conductor assembly that may include one or more
metallic members, strength members, or jackets.

Campus

The
buildings and grounds of a complex, such as a university, college,
industrial park or military establishment.

Capacitance

The
ability to store electric charge between two conductors separated
by a dielectric material. Capacitance is expressed in Farads.

Carrier

An
electrical signal of a set frequency that can be modulated in order
to carry data.

Carrier
Detect

A
circuit that detects the presence of a carrier.

Carrier
Sense

With
Ethernet, a method of detecting the presence of signal activity on
a common channel.

Carrier
Sense Multiple Access with Collision Detect

A
network access method used by Ethernet in which a station listens
for traffic before transmitting. If two stations transmit simultaneously,
a collision is detected and both stations wait a brief time before
attempting to transmit again.

Category
1, Cat 1

Unshielded
twisted pair used for transmission of audio frequencies. Used as speaker
wire, door bell wire, etc. Not suitable for networking applications.

Category
2, Cat 2

Unshielded
twisted pair used for transmission at frequencies up to 1.5 Mhz. Used
in analog telephone applications. Not suitable for networking applications.

Category
3, Cat 3

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 16 MHz. Defined by the
TIA/EIA 568-A specification.

Category
4, Cat 4

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 20 MHz. Defined by the
TIA/EIA 568-A specification.

Category
5, Cat 5

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 100 MHz. Defined by the
TIA/EIA 568-A specification.

Category
5e, Cat 5e, Enhanced Cat 5, Cat 5+

Category
5e is a new standard that will specify transmission performance that
exceeds Cat 5. Cat 5e has improved specifications for NEXT, PSELFEXT,
and Attenuation. Like Cat 5, it consists of unshielded twisted pair
with 100 ohm impedance and electrical characteristics supporting transmission
at frequencies up to 100 MHz. To be defined in the TIA 568-A-5 update.

Category
6, Cat 6

Category
6 is a proposed standard that aims to support transmission at frequencies
up to 250 MHz over 100 ohm twisted pair.

Category
7, Cat 7

Category
7 is a proposed standard that aims to support transmission at frequencies
up to 600 MHz over 100 ohm twisted pair.

CATV

Community
antenna television, or “Cable TV”. CATV is a broadband transmission
facility which generally uses a 75 Ohm coaxial cable to carry numerous
frequency-divided TV channels simultaneously.

CBX

Computerized
Branch Exchange.

Cellular
Polyethylene

Expanded
or “foam” polyethylene, a material with a reduced dielectric
constant consisting of individual closed cells of inert gas suspended
in a polyethylene medium.

CDDI

Copper
Distributed Data Interface – A version of FDDI that uses copper wire
media instead of fiber optic cable.

Channel

The
end to end transmission path between two points at which application
specific equipment is connected.

Channel
Insertion Loss

For
fiber optic links, the static loss of a link between a transmitter
and receiver. It includes the loss of the fiber, connectors, and splices.

Characteristic
Impedance

The
impedance that an infinitely long transmission line would have at
its input terminal. If a transmission line is terminated in its characteristic
impedance, it will appear (electrically) to be infinitely long, thus
minimizing signal reflections from the end of the line.

Cheapernet

Another
name for thin Ethernet or 10Base2 systems.

Chirping

Refers
to the change of optical frequency of laser diodes when the laser
diode is pulsed between two different optical power levels. Chirp
broadens the laser’s spectral width causing chromatic dispersion.

Chromatic
Dispersion

Synonym
for “material dispersion”.

Circuit

1.
A system of conducting media designed to pass a signal or voltage
between two points. 2. A bi-directional communications path between
two pieces of associated equipment.

Cladding

The
material surrounding the core of a fiber optic cable. The cladding
must have a lower index of refraction than the core in order to contain
the light in the core.

Class

ISO/IEC
11801 designation for twisted pair cabling rated to 100 KHz. Used
in voice and low frequency applications. Comparable to Category 1
cabling. Not suitable for networking applications

Class
B

ISO/IEC
11801 designation for twisted pair cabling rated to 1 MHz. Used in
medium bit rate applications. Comparable to Category 2 cabling. Not
suitable for networking applications

Class
C

ISO/IEC
11801 designation for twisted pair cabling rated to 16 MHz. Used in
high bit rate applications. Corresponds to TIA/EIA Category 3 cabling.

Class
D

ISO/IEC
11801 designation for twisted pair cabling rated to 100 MHz. Used
in very high bit rate applications. Corresponds to TIA/EIA Category
5 cabling.

Class
E

ISO/IEC
proposal for twisted pair cabling rated to 250 MHz. Corresponds to
the proposed TIA/EIA Category 6 cabling standard.

Closet

An
enclosed space for housing telecommunications and networking equipment,
cable terminations, and cross-connect cabling. It contains the horizontal
cross connect where the backbone cable cross-connects with the horizontal
cable.

Coating

Material
surrounding the cladding of the fiber for protection.

Coax,
Coaxial Cable

A
type of communication transmission cable in which a solid center conductor
is 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. Coaxial cables have a wide bandwidth and can carry many
data, voice and video conversations simultaneously.

Coherence

Refers
to the phase stability of two wave trains, from the same optical wave,
separated in time

Collision

When
electrical signals from two or more devices sharing a common data
transfer medium crash into one another. This commonly happens on Ethernet
type systems.

Conduit

A
rigid or flexible metallic or nonmetallic raceway of circular cross
section in which cables are housed for protection and to prevent burning
cable from spreading flames or smoke in the event of a fire.

Conductivity

The
ability of a material to allow the flow of electrical current. It
is the reciprocal of resistivity. Measured in “mhos” (ohms
backwards).

Conductor

A
material that offers low resistance to the flow of electrical current.

Continuity

An
uninterrupted pathway for electrical signals.

Cord

A
very flexible insulated cable.

Core

The
central region of an optical fiber through which light is transmitted.

Coupling
ratio

The
percentage of optical power transferred to the secondary output port
of a coupler relative to the total power of the primary and the secondary
output ports.

CRC

see
Cyclic Redundancy Check

Critical
angle

The
angle at the interface between core and cladding where a guided ray
in the core undergoes total internal reflection.

Cross
Connect

A
facility enabling the termination of cable elements and their interconnection,
and/or cross-connection, primarily by means of a patch cord or jumper.

Cross
Connection

A
connection scheme between cabling runs, subsystems, and equipment
using patch cords or jumpers that attach to connecting hardware at
each end.

Crossover

A
conductor which connects to a different pin number at each end.

Crossover
Cable

A
twisted pair patch cable wired in such a way as to route the transmit
signals from one piece of equipment to the receive signals of another
piece of equipment, and vice versa.

Crosstalk

The
coupling of unwanted signals from one pair within a cable to another
pair. Crosstalk can be measured at the same (near) end or far end
with respect to the signal source.

CS

Canadian
Standards Association

CSMA/CD

see
Carrier Sense Multiple Access with Collision Detect.

Current

The
flow of charge in a conductor. See “alternating current”
and “direct current”.

Current
Loop

A
two wire transmit/receive interface.

Customer
Premises

Buildings,
offices, and other structures under the control of a telecommunications
customer.

Cutoff
Wavelength

A
distinct boundary, in the wavelength spectrum, which characterizes
the mode of operation of a fiber. A fiber operating at wavelengths
lower than the cutoff wavelength is multimode while the same fiber
operating at wavelengths higher than cutoff wavelength is single mode.

Cut-through
Resistance

The
ability of a material to withstand mechanical pressure without damage.

Cyclic
Redundancy Check (CRC)

An error checking
technique used to ensure the accuracy of transmitting digital code
over a communications channel. The transmitted messages are divided
into predetermined lengths which, used as dividends, are divided
by a fixed divisor. The remainder of the calculation is appended
onto and sent with the message. At the receiving end, the computer
recalculates the remainder. If it does not match the transmitted
remainder, and error is detected.

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D

D
Connector

see Subminiature
D Connector
Data
Connector
A four position
connector for 150-ohm STP used primarily with Token-Ring networks.
Data
Grade
A term used
for twisted-pair cable used in networks to carry data signals. Data
grade media has a higher frequency rating than voice grade media
used in telephone wiring.

>
DAS Dual Attachment
Station. Term used with FDDI networks to denote a station that attaches
to both the primary and secondary rings.
dB
>
Decibel. A
unit for measuring the relative strength of a signal. Usually expressed
as the logarithmic ratio of the strength of a transmitted signal
to the strength of the original signal. A decibel is one tenth of
a “bel”.
DB-9 Nine pin D
connector.
DB-15 Fifteen pin
D connector.
DB-25 Twenty-five
pin D connector.
DC see Direct
Current.

>
DCE Data Communications
Equipment. Any equipment that connects to Data Terminal Equipment
(DTE) to allow transmission between DTEs.
DC
Loop Resistance
The total DC
resistance of a cable. For twisted pair cable, it includes the round
trip resistance, down one wire of the pair and back up the other
wire.

Demand
Priority

A network access
method used by 100VG-AnyLAN. The hub arbitrates requests for network
access received from stations, assigning access based on priority
and traffic loads.
Demarcation
Point
A point where
the operational control or ownership changes, such as the point
of interconnection between telephone company facilities and a user’s
building or residence.
DGM Data Grade
Media (see Data Grade)

>
Dielectric An insulating
(non-conducting) material.
Dielectric
Constant
The property
of a dielectric which determines the amount of electrostatic energy
that can be stored by the material when a given voltage is applied
to it. Also called permattivity.

>
Digital
Signal

>
An electric
signal which possesses two distinct states (on/off, positive/negative,
one/zero).
Direct
Current
An electric
current that flows in one direction and does not reverse direction
as with “alternating current”.
Dispersion The phenomenon
in an optical fiber whereby light photons arrive at a distant point
in different phase than they entered the fiber. Dispersion causes
receive signal distortion that ultimately limits the bandwidth and
usable length of the fiber cable. The two major types of dispersion
are 1) mode (or modal) dispersion caused by differential optical
path lengths in a multimode fiber, and 2) material dispersion caused
by differing transmission times of different wavelengths of light
in the fiber optic material.

>
Distortion Any undesired
change in a wave for or signal.
Distribution
Frame
A structure
with terminations for connecting the permanent cabling of a facility
in a manner that interconnections or cross connects may be readily
made.
DIW Direct Inside
Wire. Twisted pair wire used inside a building, usually two or four
pair AWG 26.
Drain
Wire
An uninsulated
wire in contact with a shield throughout its length. Used to terminate
the shield.
Drop
Cable
The cable which
allows connection and access to and from the trunk cables of a network
such as the cables that connect individual PCs to the bus on a bus
LAN. In a CATV system, the transmission cable from the distribution
cable to a dwelling.
DS1/DS3 see T1 and
T3
DTE Data Terminal
Equipment. Any piece of equipment at which a communications path
begins or ends.
Duct 1. A single
enclosed raceway for wires or cable. 2. An enclosure in which air
is moved.
Duplex 1. (data communications)
A circuit used to transmit signals simultaneously in both directions.
2. (general) Two receptacles or jacks in a common housing which
accepts two plugs.
align=”right”>Top

E

E1/E3

The
European versions of T1 and T3. E1 runs at 2.048 Mbps and E3 runs
at 34 Mbps.

Earth

A
term for zero reference ground.

EC

European
Community

ECM

European
Computer Manufacturer’s Association. A European trade organization
that issues its own standards and is a member of the ISO.

EI

Electronic
Industry Association (formerly RMA or RETMA). An association of manufacturers
and users that establishes standards and publishes test methodologies.

Electromagnetic
Coupling

The
transfer of energy by means of a varying magnetic field. Inductive
coupling.

Electromagnetic
Field

The
combined electric and magnetic field caused by electron motion in
conductors.

Electromagnetic
Interference

An
interfering electromagnetic signal. Network wiring and equipment may
be susceptible to EMI as well as emit EMI.

Electrostatic

Electrical
charge that exists when the charge is at rest.

Electrostatic
Coupling

The
transfer of energy by means of a varying electrostatic field. Capacitive
coupling.

ELFEXT

Equal
Level Far End Crosstalk

EMI

see
Electromagnetic Interference.

Encoding

A
means of combining clock and data information into a self-synchronized
stream of signals.

Entrance
Facility

An
entrance to a building for both public and private network service
cables (including antennae) including the entrance at the building
wall and continuing to the entrance room or space.

Entrance
Point

The
point of emergence of telecommunications conductors through an exterior
wall, a concrete floor slab, or from a rigid metal conduit or intermediate
metal conduit.

Entrance
Room

A
space in which the joining of inter- or intra-building telecommunications
or networking backbone facilities takes place. An entrance room may
also serve as an equipment room.

Equipment
Room

An
enclosed area housing telecommunications and network equipment, distinguished
from the telecommunications or wiring closet by its increased complexity
and presence of active equipment.

EPDM

Ethylene-propylene-diene
monomer rubber. A material with good insulating properties.

EPR

Ethylene-propylene
copolymer rubber. A material with good insulating properties.

Ethernet

A local area
network (LAN) protocol defined in the IEEE 802.3 standard in which
computers access the network through a Carrier Sense Multiple Access
/ Collision Detect (CSMA/CD) protocol.

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F

f

Frequency

Farad

A
unit of capacitance that stores one coulomb of electrical charge when
one volt of electrical pressure is applied.

Far
End Cross Talk (FEXT)

Crosstalk
that is measured on the quiet line at the opposite end as the source
of energy on the active line. FEXT is not typically measured in cabling,
with Near End Cross Talk (NEXT) being the preferred crosstalk measurement.

Fast
Ethernet

Ethernet
standard supporting 100 Mbps operation.

FCC

Federal
Communications Commission.

FCS

Frame
Check Sequence. Error detection field.

FDDI

Fiber
Distributed Data Interface. An ANSI Standard (ANSI X3T12) for a 100
Mbps token passing network based on fiber-optic (FDDI) and twisted-pair
(CDDI) cabling.

Feeder
Cable

In
a CATV system, the transmission cable from the head end (signal pickup)
to the trunk amplifier. Also called a trunk cable.

FEP

Fluorinated
ethylene propylene. A thermoplastic with excellent dielectric properties
which is often used as insulation in fire rated cables.

FEXT

see
Far End Cross Talk

Fiber
Optics

The
technology in which communication signals in the form of modulated
light beams are transmitted over a glass fiber transmission medium.
Fiber optic technology offers high bandwidth, small space needs and
protection from electromagnetic interference, eavesdropping and radioactivity.

Fifty-pin
Connector

Commonly
referred to as a Telco, CHAMP, or blue ribbon connector, this connector
is used on Ethernet 10Base-T hubs as an alternate twisted-pair segment
connection method. The 50-pin connector connects to 25-pair cables,
which are frequently used in telephone wiring systems and which typically
meet Category 3 specifications.

Fillers

Nonconducting
components cabled with the insulated conductors or optical fibers
to impart roundness, flexibility, tensile strength, or a combination
of all three.

Floating

Refers
to a circuit that has no connection to ground.

FOIRL

Fiber
Optic Inter-Repeater Link. An Ethernet fiber optic connection method
intended for connection of repeaters.

Frequency

The
number of times a periodic action occurs in a unit of time. Expressed
in hertz (abbreviated Hz). One hertz equals one cycle per second.

Frequency
Division Multiplexing (FDM)

A
technique for combining many signals on a single circuit by dividing
the available transmission bandwidth by frequency into narrower bands,
each used for a separate communication channel.

Frequency
Modulation (FM)

One
of three basic methods (see also Amplitude and Phase Modulation) of
adding information to a sine wave signal in which its frequency is
varied to impose information on it.

Frequency
Response

The
range of frequencies over which a device operates as expected.

FTP

see
Screened Twisted Pair (ScTP) cable

Full
Duplex Transmission

Data transmission
over a circuit capable of transmitting in both directions simultaneously.

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G

G

Green

Gbps

Gigabits
per second.

Gig

A
prefix meaning one billion

GigaHertz
(GHz)

One
billion hertz.

GIPOF

Graded
Index Plastic Optical Fiber

Graded
Index Fiber

A
multimode fiber optic cable design in which the index of refraction
of the core is lower toward the outside of the core and progressively
increases toward the center of the core, thereby reducing modal dispersion
of the signal.

Ground

A
common point of zero potential such as a metal chassis or ground rod.

Ground
Loop

A condition
where an unintended connection to ground is made through an interfering
electrical conductor.

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H

Half
Duplex Transmission

Data
transmission over a circuit capable of transmitting in either direction,
but not simultaneously.

HC

see
Horizontal Cross Connect.

Head
end

The
equipment in a cable system which receives the various program source
signals, processes them, and retransmits them to subscribers.

Headroom

The
amount by which a cable ACR exceeds 10dB.

Hertz

The
unit of frequency, one cycle per second (abbreviated Hz).

HF

High
Frequency

Home
Run

A
cable run that connects a user outlet directly with the telecommunications
or wiring closet, with no intermediate splices, bridges, taps, or
other connections.

Horizontal
Cabling, Horizontal Wiring

The
portion of the cabling system that extends from the work area outlet
to the horizontal cross connect in the telecommunications or wiring
closet.

Horizontal
Cross Connect

A
cross connect of horizontal cabling to other cabling, e.g. horizontal,
backbone, or equipment.

Host

Computer
that offers services on a network.

Hub

A
hardware device that contains multiple independent but connected modules
of network and internetworking equipment. Hubs can be active (where
they repeat signals set to them) or passive (where they do not repeat
but merely split signals sent through them). Hub may also refer to
a repeater, bridge, switch, router, or any combination of these.

HVAC

Heating,
ventilation, and air conditioning system.

Hybrid
Cable

An
assembly of two or more cables (of the same or different types or
categories) covered by one overall sheath.

Hypalon

A Dupont trade
name for a synthetic rubber (chlorosulfonated polyethylene) used
as insulating and jacketing material for cabling.

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I

I

Symbol
used to designate current.

IC

see
Intermediate Cross Connect.

ICE

Insulated
Cable Engineers Association

ICS

IBM
Cabling System

IDC

Insulation
Displacement Contact/Connector

IDF

Intermediate
Distribution Frame. This is usually located on each floor within a
building. It is tied directly to the Main Distribution Frame via cables.

IEC

International
Electro technical Commission

IEEE

Institute
of Electrical and Electronics Engineers. A professional organization
and standards body. The IEEE Project 802 is the group within IEEE
responsible for LAN technology standards.

IEEE
802.1

The
IEEE standards committee defining High Level Interfaces, Network Management,
Internetworking, and other issues common across LAN technologies.

IEEE
802.2

The
IEEE standards committee defining Logical Link Control (LLC).

IEEE
802.3

The
IEEE standards committee defining Ethernet networks.

IEEE
802.5

The
IEEE standards committee defining Token-Ring standards.

Impedance

A
unit of measure, expressed in Ohms, of the total opposition (resistance,
capacitance and inductance) offered to the flow of an alternating
current.

Impedance
Match

A
condition where the impedance of a particular circuit cable or component
is the same as the impedance of the circuit, cable, or device to which
it is connected.

Impedance
Matching Transformer

A
transformer designed to match the impedance of one circuit to another.

Index
of Refraction

The
ratio of light velocity in a vacuum to its velocity in a given transmission
medium.

Infrastructure,
Telecommunications

A
collection of those telecommunications components, excluding equipment,
that together provide the basic support for the distribution of all
information within a building or campus.

Interconnection

A
connection scheme that provides for the direct connection of a cable
to another cable or to an equipment cable without a patch cord or
jumper.

Intermediate
Cross Connect

A
cross-connect between 1st level and 2nd level backbone cabling.

Injection
Laser Diode

A
semiconductor laser in which the lasing occurs at the junction of
n-type and p-type semiconductor materials.

Insertion
Loss

A
measure of the attenuation of a device by determining the output of
a system before and after the device is inserted into the system.
For example, a connector causes insertion loss across the interconnection
(in comparison to a continuous cable with no interconnection).

ISDN

Integrated
Services Digital Network

ISO

International
Standards Organization

Isolated
Ground

A
separate ground conductor which is insulated from the equipment or
building ground.

Isolation

The
ability of a circuit or component to reject interference.

Insulation

A
material which is nonconductive to the flow of electrical current.

Interference

Undesirable
signals which interfere with the normal operation of electronic equipment
or electronic transmission.

Isochronous

Signals
which are dependent on some uniform timing or carry their own timing
information imbedded as part of the signal. Voice and video signals
are isochronous signals, but data transfer is generally not.

ITU

International
Telecommunications Union. An international organization that develops
communications standards.

Top


J

Jabber

Term
used with Ethernet to describe the act of continuously sending data.
A jabbering station is one whose circuitry or logic has failed, and
which has locked up a network channel with its incessant transmission.

Jack

A
female connector.

Jacket

The
outer protective covering of a cable.

Jitter

The
slight movement of a transmission signal in time or phase that can
introduce errors and loss of synchronization. More jitter will be
encountered with longer cables, cables with higher attenuation, and
signals at higher data rates. Also, called phase jitter, timing distortion,
or intersymbol interference.

Jumper

An assembly
of twisted pairs without connectors used to used to join telecommunications
circuits at the cross connect. Similar to a patch cable (which has
connectors).

Top


K

Keying

The mechanical
feature of a connector system that guarantees correct orientation
of a connection, or prevents the connection to a jack, or to an
optical fiber adapter, of the same type intended for another purpose.

Top


L

L

Symbol
used to designate inductance.

LAN

Local
Area Network

LAN
Adapter

see
Network Interface Card

Laser

Light
Amplification by Stimulated Emission of Radiation. A device which
produces light with a narrow spectral width. Used in fiber optic communication
systems, usually single mode, where high capacity and low attenuation
are required.

LAT

Local
Access and Transport Area.

Lay

The
axial distance required for one cabled conductor or conductor strand
to complete one revolution about the axis around which it is cabled.

Lay
Direction

The
direction of the progressing spiral twist in while looking along the
axis of the cable away from the observer. The lay direction can be
either “left” or “right”.

LCL

see
Longitudinal Conversion Loss

LCTL

see
Longitudinal Conversion Transfer Loss

Leakage

An
undesirable passage of current over the surface of or through a connector.

Leased
Line

A
private telephone line rented for the exclusive use of a leasing customer,
without interchange switching arrangements.

LED

see
Light Emitting Diode.

LF

Low
frequency.

Light
Emitting Diode

A
semiconductor diode which emits incoherent light when a current is
passed through it. Used as a light source in fiber optic transmission.

Link

A
transmission path between two points not including terminal equipment,
work area cables, or equipment cables.

Listed

Equipment
included on a list published by an organization, acceptable to the
authority having jurisdiction, that maintains periodic inspection
of production of listed equipment, and whose listing states either
that the equipment or material meets appropriate standards or has
been tested and found suitable for use in a specified manner.

Lobe

An
arm of a Token-Ring which extends from a Multistation Access Unit
(MSAU) to a workstation adapter.

LocalTalk

A
low-speed form of LAN data link technology, part of Apple Computer’s
AppleTalk networking scheme, that uses a carrier sense multiple access
with collision avoidance (CSMA/CA) form of medium access control.
Supports transmission at 230 Kbps.

Longitudinal
Conversion Loss (LCL)

Also
called near-end unbalance attenuation, measures cable balance by comparing
the signal appearing across the pair to the signal applied between
ground and the pair, where the applied signal and the across pair
signal are at the same end of the cable.

Longitudinal
Conversion Transfer Loss (LCTL)

Also
called far-end unbalance attenuation, measures cable balance by the
comparison of the signal appearing across the pair to the signal between
ground and the pair, where the applied signal is at the opposite end
of the cable from where the across pair signal is measured.

Loopback

A
type of diagnostic test in which a transmitted signal is returned
to the sending device after passing through a data communications
link or network. This test allows the comparison of a returned signal
with the transmitted signal.

Loss

The
portion of energy applied to a system that is dissipated and performs
no useful work.

Lossy

Having poor
efficiency.

Top


M

M

Mutual
Inductance

m

Milliampere
(one thousandth of an ampere)

MAC

see
Medium Access Control

Main
Cross Connect

A
cross connect for first level backbone cables, entrance cables, and
equipment cables. The main cross connect is at the top level of the
premises cabling tree.

Manchester
Coding

A
method of LAN signal encoding in which each bit time that represents
a data bit has a transition in the middle of the bit time. Used with
10 Mbps Ethernet (10Base2, 10Base5, 10Base-F, & 10Base-T), and
Token-Ring LANs.

Material
Dispersion

Dispersion
that results from each wavelength traveling at a different speed than
other wavelengths through an optical fiber. Also called “chromatic
dispersion”.

MAU

Media
Attachment Unit. The transceiver in Ethernet networks. Also a common
name for the MSAU (Multi-station Access Unit) in Token-Ring networks.

Mbaud

Megabaud.
One million baud.

Mbps

Megabits
per second.

MC

see
Main Cross Connect

MDF

Main
Distribution Frame

MDI

see
Media Dependent Interface

Medi

Wire,
cable, or conductors used for transmission of signals.

Media
Filter

An
impedance matching component used in Token-Ring networks to transform
the 100 ohm impedance of UTP cabling to the 150 ohm impedance of media
interface connections.

Medium
Access Control (MAC)

A
mechanism operating at the data link layer of local area networks
which manages access to the communications channel (medium).

Medium
Dependent Interface (MDI)

In
Ethernet, the connector used to make the mechanical and electrical
interface between a transceiver and a media segment. An 8-pin RJ-45
connector is the MDI for the 10Base-T, 100Base-TX, 100Base-T2, 100Base-T4,
and 1000Base-T media systems.

Medium
Independent Interface (MII)

Used
with 100 Mbps Ethernet systems to attach MAC level hardware to a variety
of physical media systems. Similar to the AUI interface used with
10 Mbps Ethernet systems. An MII provides a 40-pin connection to outboard
transceivers (also called PHY devices).

Meg

Prefix
meaning one million.

Megahertz
(MHz)

One
million hertz.

MIC

Medium
Interface Connector. Duplex fiber optic connector used with Fiber
Distributed Data Interface (FDDI) networks.

Micro

Prefix
meaning one millionth.

Microfarad

One
millionth of a farad. Abbreviated µF (less commonly µfd, mf, and mfd).

Micron

One
millionth of a meter. Abbreviated µm.

Midsplit
Broadband

A
broadcast network configuration in which the cable is divided into
two channels, each using a different range of frequencies. One channel
is used to transmit signals and the other is used to receive.

MII

see
Medium Independent Interface.

Mil

Unit
of length equal to one thousandth of an inch (0.001 inch).

Milli

Prefix
meaning one thousandth.

Mixing
Segment

Ethernet
term used in IEEE 802.3 standards to describe a segment that may have
more than two MDI connections.

MMF

set
Multimode Fiber

Modal
Dispersion

Dispersion
that results from the different transit lengths of different propagating
modes in a multimode optical fiber.

Mode

A
single electromagnetic wave traveling in an optical fiber.

Mode
Field Diameter

The
diameter of optical energy in a single mode fiber. Because the mode-field
diameter is larger than the core diameter, it replaces core diameter
as a practical parameter.

Modem

A
device that implements “modulator-demodulator” functions
to convert between digital data and analog signals.

Modular
Jack

The
equipment mounted half of a modular interconnection. Typically a female
connector. A modular jack may be keyed or unkeyed and may have six
or eight contact positions, but not all the positions need to be equipped
with jack contacts.

Modular
Plug

The
cable mounted half of a modular interconnection. Typically a male
connector. A modular plug may be keyed or unkeyed and may have six
or eight contact positions, but not all the positions need to be equipped
with contacts.

Modulation

Altering
the characteristics of a carrier wave to convey information. Modulation
techniques include amplitude, frequency, phase, plus many other forms
of digital encoding.

MSAU

Multi-station
Access Unit. Device used to interconnect lobe cables from stations
on a Token-Ring network.

MT-RJ

Proposal
for a new duplex fiber optic connector standard from AMP/Siecor.

Multimode
Fiber

A
fiber optic cable which supports the propagation of multiple modes.
Multimode fiber may have a typical core diameter of 50 to 100 µm with
a refractive index that is graded or stepped. It allows the use of
inexpensive LED light sources and connector alignment and coupling
is less critical than single mode fiber. Distances of transmission
and transmission bandwidth are less than with single mode fiber due
to dispersion.

Mutual
Capacitance

Capacitance
between two conductors when all other conductors are connected together.

mV

Millivolt
(one thousandth of a volt)

mW

Milliwatt
(one thousandth of a watt)

Mylar

Dupont
trademark for polyethylene terephtalete (polyester) film.

N

N

see
Numerical Aperture

N
connector

A
coaxial connector used for Ethernet 10Base5 thick coax segments.

Nanometer
(nm)

One
billionth of a meter.

Nanosecond
(ns)

Butadiene-acrylonitrile
copolymer rubber, a material with good oil and chemical resistance.

NBR

One
billionth of a second.

Near-End
Crosstalk

Crosstalk
between two twisted pairs measured at the same end of the cable as
the disturbing signal source. NEXT is the measurement of interest
for crosstalk specifications.

NEC

National
Electrical Code.

NEM

National
Electrical Manufacturers Association.

Neoprene

A
synthetic rubber with good resistance to oil, chemical, and flame.
Also called polychloroprene.

Network

An
interconnection of computer systems, terminals or data communications
facilities.

Network
Interface Card

A
circuit board installed in a computing device used to attach the device
to a network. A NIC performs the hardware functions that are required
to provide a computing device with physical communications capabilities.
Also Network Interface Unit (NIU).

NEXT

see
Near-End Crosstalk.

NFP

National
Fire Protection Association

Nibble

One
half byte.

NIC

see
Network Interface Card.

NIR

Near-end
Crosstalk-to-Insertion Loss Ratio

Node

End
point of a network connection. Nodes include any device connected
to a network such as file servers, printers, or workstations.

Noise

In
a cable or circuit, any extraneous signal which interferes with the
desired signal.

Nomex

Dupont
trademark for a temperature-resistant, flame retardant nylon.

NRZ

Non
Return to Zero.

NRZI

Non
Return to Zero Inverted.

Numerical
Aperture (NA)

The
“light gathering ability” of an optical fiber, defining
the maximum angle to the fiber axis at which light will be accepted
and propagated.

NVP

Nominal
Velocity of Propagation. The speed a signal propagates through a cable
expressed as a decimal fraction of the speed of light in a vacuum.

Nylon

An abrasion
resistant thermoplastic with good chemical resistance.

Top

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

Top


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-

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”.

TI

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
Medi

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
1

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
2

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
6

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
9

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.

V

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
Are

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

Top



A B
C D
E F
G H
I J
K L
M N
O
P
Q R
S T
U V
W X
Y Z
0-9





Ampere
– A unit of measure of electrical current.

AC

see
Alternating Current.

Acceptance
Angle

The
largest angle that a guided ray of light is accepted by a fiber optic
cable.

Access
Method

The
rules by which a network device gains the rights to transmit a communication
on the network. Common methods include carrier sense multiple access
with collision detection, token passing, and demand priority.

ACR

see
Attenuation Crosstalk Ratio.

Alternating
Current

An
electric current that cyclically reverses the direction of flow. Frequency
is the rate at which a full cycle occurs in one second.

Amplitude

The
maximum value of a varying signal.

Amplitude
Modulation

One
of three basic methods (see also Frequency and Phase Modulation) of
adding information to a sine wave signal in which the magnitude of
the signal is varied to impose information on it.

ANSI

American
National Standards Institute

Analog
Signal

An
electrical signal that varies continuously without having discrete
values (as with a “digital” signal).

AppleTalk

Apple
Computer’s networking scheme, integrated into most Apple system software,
that allows Apple computing systems to participate in peer to peer
computer networks and to also access the services of AppleTalk servers.
See also LocalTalk.

ARCnet

Attached
Resource Computer Network. A relatively low speed form of LAN data
link technology (2.5 Mbps) developed by Datapoint, in which all systems
are attached to a common coaxial cable. ARCnet uses a token-bus form
of medium access control in which a system transmits only when it
has the token

Asynchronous

Transmission
where sending and receiving devices are not synchronized. Data must
carry signals to indicate data division.

Asynchronous
Transfer Mode (ATM)

A
form of very fast packet switching in which data is carried in fixed
length units called “cells”. Each cell is 53 bytes in length,
with 5 bytes used as a header in each cell. ATM employs mechanisms
that can be used to set up virtual circuits between users, in which
a pair of users appear to have a dedicated circuit between them. ATM
is defined in specifications from the ITU and ATM Forum.

Attachment
Unit Interface.

The
IEEE 802.3 standard name for the cable connecting an Ethernet transceiver
(MAU) to a networked device. An AUI cable is equipped with a 15-pin
connector that mates with a 15-pin connector on the networked device.

Attenuation

The
decrease in magnitude of a signal as it travels through any transmission
medium such as a cable or optical fiber. Measured in dB per unit of
length.

Attenuation
Crosstalk Ratio (ACR)

The
difference between attenuation and crosstalk, measured in dB, at a
given frequency. A quality factor for cabling to assure that signal
sent down a twisted pair is stronger at the receiving end of the cable
than any interference imposed on the same pair by crosstalk from other
pairs.

Audio

Used
to describe the range of frequencies within range of human hearing;
approximately 20 to 20,000 Hz.

AUI

see
Attachment Unit Interface.

AWG

American Wire
Gage – A wire diameter specification. The smaller the AWG number,
the larger the wire diameter.

Top


B

Backbone

A
cable connection between telecommunication or wiring closets, floor
distribution terminals, entrance facilities, and equipment rooms either
within or between buildings. In star networks, the backbone cable
interconnects hubs and similar devices, as opposed to cables running
between hub and station. In a bus network, the bus cable.

Back
reflection

The
light reflected back towards the source from the fiber optic ends
and deformations.

Backscattering

Refers
to light diffraction at microscopic non-uniformities in the index
of refraction of the optical fiber causing back reflection of optical
power towards the source.

Balanced
Cable, Balanced Line

A
cable having two identical conductors that carry voltages of opposite
polarities and equal magnitude with respect to ground. The conductors
are twisted to maintain balance over a distance.

Balanced
Transmission

A
mode of signal transmission in which each conductor carries the signal
of equal magnitude, but opposite polarity. A 5 volt signal for example,
appears as a +2.5 Volts on one conductor and -2.5 Volts on the other.

Balun

An
impedance matching transformer that converts the impedance of one
interface to the impedance of another interface. Generally used to
connect balanced twisted pair cabling with unbalanced coaxial cabling.
The term is derived from “balanced / unbalanced”.

Band
pass

A
range of frequencies or wavelengths within which a component operates.

Baseband

A
transmission method in which the entire bandwidth of the transmission
medium is used to transmit a single digital signal. The signal is
driven directly onto the transmission medium without modulation of
any kind. Baseband is simpler, cheaper and less sophisticated than
Broadband.

Bandwidth

The
range of frequencies required for proper transmission of a signal.
Expressed in Hertz (cycles per second). The higher the bandwidth,
the more information that can be carried. A continuous range starting
from zero is said to be “baseband”, while a range starting
substantially above zero is “broadband”.

Baud

The
number of changes in signal per second. A given baud rate does not
necessarily transmit an equal number of bits/sec. For example, a signal
with four voltage levels may be used to transfer two bits of information
for every baud.

Beacon

A
special frame in Token-Ring systems indicating a serious problem with
the ring such as a break.

BEL

A
unit that represents the logarithm of the ratio of two levels.

Bend
Loss

A
form of increased attenuation in an optical fiber caused by an excessively
small bend radius. The attenuation may be permanent if micro fractures
caused by the bend continue to affect transmission of the light signal.

Bend
Radius

Radius
of curvature that a fiber optic or metallic cable can bend before
the risk of breakage or increased attenuation occurs.

BER

see
Bit Error Rate

BICSI

Building
Industry Consulting Service International.

Binder

A
tape or thread used to hold assembled cable components in place.

BISDN

Broadband
ISDN

Bit

One
binary digit.

Bit
Error Rate

A
measure of data integrity, expressed as the ratio of received bits
that are in error, relative to the amount of bits received. Often
expressed as a negative power of ten.

Bit
Stream

A
continuous transfer of bits over some medium.

Bit
Stuffing

A
method of breaking up continuous strings of 1 bits by inserting a
0 bit. The 0 bit is removed at the receiver.

Bit
Time

The
length of time required to transmit one bit of information.

BL

Blue.

BNC

A
coaxial connector that uses a “bayonet” style turn and lock
mating method. Used with RG-58 or smaller coaxial cable. Used with
10Base2 Ethernet thin coaxial cable. BNC is an acronym for Bayonet-Neill-Concelman.

Bonding

A
method used to produce good electrical contact between metallic parts.
Also refers to the grounding bars and straps used in buildings to
bond equipment to an approved ground.

BPS

Bits
per second.

BR

Brown.

Braid

Fine
wires interwoven to form a tubular flexible structure that may be
applied over one or more wires for the purpose of shielding. May also
be formed into a flattened conductor to be used as a grounding strap.

BRI

ISDN
Basic Rate Interface

Bridged
Tap

Multiple
appearances of the same cable pair at several distribution points.

Broadband

A
transmission facility having a bandwidth sufficient to carry multiple
voice, video or data channels simultaneously. Each channel occupies
(is modulated to) a different frequency bandwidth on the transmission
medium and is demodulated to its original frequency at the receiving
end. Channels are separated by “guard bands” (empty spaces)
to ensure that each channel will not interfere with its neighboring
channels. This technique is used to provide many CATV channels on
one coaxial cable.

Broadcast

Sending
data to more than one receiving device at a time.

Buffer

A
protective coating over a strand of optical fiber.

Bus
Topology

1.
In general, a physical layout of network devices in which all devices
must share a common medium to transfer data, and no two devices may
transmit simultaneously. 2. With LANs, a linear network topology in
which all computers are connected to a single cable.

Butyl
Rubber

A
synthetic rubber with good electrical insulating properties.

Byte

A group of 8
bits.

Top


C

c

A
small “c” is the symbol for the speed of light in a vacuum.

C

A
capital “C” is the designation for Celsius.

Cable

A
group of insulated conductors enclosed within a common jacket.

Cable
Sheath

A
covering over the conductor assembly that may include one or more
metallic members, strength members, or jackets.

Campus

The
buildings and grounds of a complex, such as a university, college,
industrial park or military establishment.

Capacitance

The
ability to store electric charge between two conductors separated
by a dielectric material. Capacitance is expressed in Farads.

Carrier

An
electrical signal of a set frequency that can be modulated in order
to carry data.

Carrier
Detect

A
circuit that detects the presence of a carrier.

Carrier
Sense

With
Ethernet, a method of detecting the presence of signal activity on
a common channel.

Carrier
Sense Multiple Access with Collision Detect

A
network access method used by Ethernet in which a station listens
for traffic before transmitting. If two stations transmit simultaneously,
a collision is detected and both stations wait a brief time before
attempting to transmit again.

Category
1, Cat 1

Unshielded
twisted pair used for transmission of audio frequencies. Used as speaker
wire, door bell wire, etc. Not suitable for networking applications.

Category
2, Cat 2

Unshielded
twisted pair used for transmission at frequencies up to 1.5 Mhz. Used
in analog telephone applications. Not suitable for networking applications.

Category
3, Cat 3

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 16 MHz. Defined by the
TIA/EIA 568-A specification.

Category
4, Cat 4

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 20 MHz. Defined by the
TIA/EIA 568-A specification.

Category
5, Cat 5

Unshielded
twisted pair with 100 ohm impedance and electrical characteristics
supporting transmission at frequencies up to 100 MHz. Defined by the
TIA/EIA 568-A specification.

Category
5e, Cat 5e, Enhanced Cat 5, Cat 5+

Category
5e is a new standard that will specify transmission performance that
exceeds Cat 5. Cat 5e has improved specifications for NEXT, PSELFEXT,
and Attenuation. Like Cat 5, it consists of unshielded twisted pair
with 100 ohm impedance and electrical characteristics supporting transmission
at frequencies up to 100 MHz. To be defined in the TIA 568-A-5 update.

Category
6, Cat 6

Category
6 is a proposed standard that aims to support transmission at frequencies
up to 250 MHz over 100 ohm twisted pair.

Category
7, Cat 7

Category
7 is a proposed standard that aims to support transmission at frequencies
up to 600 MHz over 100 ohm twisted pair.

CATV

Community
antenna television, or “Cable TV”. CATV is a broadband transmission
facility which generally uses a 75 Ohm coaxial cable to carry numerous
frequency-divided TV channels simultaneously.

CBX

Computerized
Branch Exchange.

Cellular
Polyethylene

Expanded
or “foam” polyethylene, a material with a reduced dielectric
constant consisting of individual closed cells of inert gas suspended
in a polyethylene medium.

CDDI

Copper
Distributed Data Interface – A version of FDDI that uses copper wire
media instead of fiber optic cable.

Channel

The
end to end transmission path between two points at which application
specific equipment is connected.

Channel
Insertion Loss

For
fiber optic links, the static loss of a link between a transmitter
and receiver. It includes the loss of the fiber, connectors, and splices.

Characteristic
Impedance

The
impedance that an infinitely long transmission line would have at
its input terminal. If a transmission line is terminated in its characteristic
impedance, it will appear (electrically) to be infinitely long, thus
minimizing signal reflections from the end of the line.

Cheapernet

Another
name for thin Ethernet or 10Base2 systems.

Chirping

Refers
to the change of optical frequency of laser diodes when the laser
diode is pulsed between two different optical power levels. Chirp
broadens the laser’s spectral width causing chromatic dispersion.

Chromatic
Dispersion

Synonym
for “material dispersion”.

Circuit

1.
A system of conducting media designed to pass a signal or voltage
between two points. 2. A bi-directional communications path between
two pieces of associated equipment.

Cladding

The
material surrounding the core of a fiber optic cable. The cladding
must have a lower index of refraction than the core in order to contain
the light in the core.

Class

ISO/IEC
11801 designation for twisted pair cabling rated to 100 KHz. Used
in voice and low frequency applications. Comparable to Category 1
cabling. Not suitable for networking applications

Class
B

ISO/IEC
11801 designation for twisted pair cabling rated to 1 MHz. Used in
medium bit rate applications. Comparable to Category 2 cabling. Not
suitable for networking applications

Class
C

ISO/IEC
11801 designation for twisted pair cabling rated to 16 MHz. Used in
high bit rate applications. Corresponds to TIA/EIA Category 3 cabling.

Class
D

ISO/IEC
11801 designation for twisted pair cabling rated to 100 MHz. Used
in very high bit rate applications. Corresponds to TIA/EIA Category
5 cabling.

Class
E

ISO/IEC
proposal for twisted pair cabling rated to 250 MHz. Corresponds to
the proposed TIA/EIA Category 6 cabling standard.

Closet

An
enclosed space for housing telecommunications and networking equipment,
cable terminations, and cross-connect cabling. It contains the horizontal
cross connect where the backbone cable cross-connects with the horizontal
cable.

Coating

Material
surrounding the cladding of the fiber for protection.

Coax,
Coaxial Cable

A
type of communication transmission cable in which a solid center conductor
is 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. Coaxial cables have a wide bandwidth and can carry many
data, voice and video conversations simultaneously.

Coherence

Refers
to the phase stability of two wave trains, from the same optical wave,
separated in time

Collision

When
electrical signals from two or more devices sharing a common data
transfer medium crash into one another. This commonly happens on Ethernet
type systems.

Conduit

A
rigid or flexible metallic or nonmetallic raceway of circular cross
section in which cables are housed for protection and to prevent burning
cable from spreading flames or smoke in the event of a fire.

Conductivity

The
ability of a material to allow the flow of electrical current. It
is the reciprocal of resistivity. Measured in “mhos” (ohms
backwards).

Conductor

A
material that offers low resistance to the flow of electrical current.

Continuity

An
uninterrupted pathway for electrical signals.

Cord

A
very flexible insulated cable.

Core

The
central region of an optical fiber through which light is transmitted.

Coupling
ratio

The
percentage of optical power transferred to the secondary output port
of a coupler relative to the total power of the primary and the secondary
output ports.

CRC

see
Cyclic Redundancy Check

Critical
angle

The
angle at the interface between core and cladding where a guided ray
in the core undergoes total internal reflection.

Cross
Connect

A
facility enabling the termination of cable elements and their interconnection,
and/or cross-connection, primarily by means of a patch cord or jumper.

Cross
Connection

A
connection scheme between cabling runs, subsystems, and equipment
using patch cords or jumpers that attach to connecting hardware at
each end.

Crossover

A
conductor which connects to a different pin number at each end.

Crossover
Cable

A
twisted pair patch cable wired in such a way as to route the transmit
signals from one piece of equipment to the receive signals of another
piece of equipment, and vice versa.

Crosstalk

The
coupling of unwanted signals from one pair within a cable to another
pair. Crosstalk can be measured at the same (near) end or far end
with respect to the signal source.

CS

Canadian
Standards Association

CSMA/CD

see
Carrier Sense Multiple Access with Collision Detect.

Current

The
flow of charge in a conductor. See “alternating current”
and “direct current”.

Current
Loop

A
two wire transmit/receive interface.

Customer
Premises

Buildings,
offices, and other structures under the control of a telecommunications
customer.

Cutoff
Wavelength

A
distinct boundary, in the wavelength spectrum, which characterizes
the mode of operation of a fiber. A fiber operating at wavelengths
lower than the cutoff wavelength is multimode while the same fiber
operating at wavelengths higher than cutoff wavelength is single mode.

Cut-through
Resistance

The
ability of a material to withstand mechanical pressure without damage.

Cyclic
Redundancy Check (CRC)

An error checking
technique used to ensure the accuracy of transmitting digital code
over a communications channel. The transmitted messages are divided
into predetermined lengths which, used as dividends, are divided
by a fixed divisor. The remainder of the calculation is appended
onto and sent with the message. At the receiving end, the computer
recalculates the remainder. If it does not match the transmitted
remainder, and error is detected.

Top


D

D
Connector

see Subminiature
D Connector
Data
Connector
A four position
connector for 150-ohm STP used primarily with Token-Ring networks.
Data
Grade
A term used
for twisted-pair cable used in networks to carry data signals. Data
grade media has a higher frequency rating than voice grade media
used in telephone wiring.

>
DAS Dual Attachment
Station. Term used with FDDI networks to denote a station that attaches
to both the primary and secondary rings.
dB
>
Decibel. A
unit for measuring the relative strength of a signal. Usually expressed
as the logarithmic ratio of the strength of a transmitted signal
to the strength of the original signal. A decibel is one tenth of
a “bel”.
DB-9 Nine pin D
connector.
DB-15 Fifteen pin
D connector.
DB-25 Twenty-five
pin D connector.
DC see Direct
Current.

>
DCE Data Communications
Equipment. Any equipment that connects to Data Terminal Equipment
(DTE) to allow transmission between DTEs.
DC
Loop Resistance
The total DC
resistance of a cable. For twisted pair cable, it includes the round
trip resistance, down one wire of the pair and back up the other
wire.

Demand
Priority

A network access
method used by 100VG-AnyLAN. The hub arbitrates requests for network
access received from stations, assigning access based on priority
and traffic loads.
Demarcation
Point
A point where
the operational control or ownership changes, such as the point
of interconnection between telephone company facilities and a user’s
building or residence.
DGM Data Grade
Media (see Data Grade)

>
Dielectric An insulating
(non-conducting) material.
Dielectric
Constant
The property
of a dielectric which determines the amount of electrostatic energy
that can be stored by the material when a given voltage is applied
to it. Also called permattivity.

>
Digital
Signal

>
An electric
signal which possesses two distinct states (on/off, positive/negative,
one/zero).
Direct
Current
An electric
current that flows in one direction and does not reverse direction
as with “alternating current”.
Dispersion The phenomenon
in an optical fiber whereby light photons arrive at a distant point
in different phase than they entered the fiber. Dispersion causes
receive signal distortion that ultimately limits the bandwidth and
usable length of the fiber cable. The two major types of dispersion
are 1) mode (or modal) dispersion caused by differential optical
path lengths in a multimode fiber, and 2) material dispersion caused
by differing transmission times of different wavelengths of light
in the fiber optic material.

>
Distortion Any undesired
change in a wave for or signal.
Distribution
Frame
A structure
with terminations for connecting the permanent cabling of a facility
in a manner that interconnections or cross connects may be readily
made.
DIW Direct Inside
Wire. Twisted pair wire used inside a building, usually two or four
pair AWG 26.
Drain
Wire
An uninsulated
wire in contact with a shield throughout its length. Used to terminate
the shield.
Drop
Cable
The cable which
allows connection and access to and from the trunk cables of a network
such as the cables that connect individual PCs to the bus on a bus
LAN. In a CATV system, the transmission cable from the distribution
cable to a dwelling.
DS1/DS3 see T1 and
T3
DTE Data Terminal
Equipment. Any piece of equipment at which a communications path
begins or ends.
Duct 1. A single
enclosed raceway for wires or cable. 2. An enclosure in which air
is moved.
Duplex 1. (data communications)
A circuit used to transmit signals simultaneously in both directions.
2. (general) Two receptacles or jacks in a common housing which
accepts two plugs.
align=”right”>Top

E

E1/E3

The
European versions of T1 and T3. E1 runs at 2.048 Mbps and E3 runs
at 34 Mbps.

Earth

A
term for zero reference ground.

EC

European
Community

ECM

European
Computer Manufacturer’s Association. A European trade organization
that issues its own standards and is a member of the ISO.

EI

Electronic
Industry Association (formerly RMA or RETMA). An association of manufacturers
and users that establishes standards and publishes test methodologies.

Electromagnetic
Coupling

The
transfer of energy by means of a varying magnetic field. Inductive
coupling.

Electromagnetic
Field

The
combined electric and magnetic field caused by electron motion in
conductors.

Electromagnetic
Interference

An
interfering electromagnetic signal. Network wiring and equipment may
be susceptible to EMI as well as emit EMI.

Electrostatic

Electrical
charge that exists when the charge is at rest.

Electrostatic
Coupling

The
transfer of energy by means of a varying electrostatic field. Capacitive
coupling.

ELFEXT

Equal
Level Far End Crosstalk

EMI

see
Electromagnetic Interference.

Encoding

A
means of combining clock and data information into a self-synchronized
stream of signals.

Entrance
Facility

An
entrance to a building for both public and private network service
cables (including antennae) including the entrance at the building
wall and continuing to the entrance room or space.

Entrance
Point

The
point of emergence of telecommunications conductors through an exterior
wall, a concrete floor slab, or from a rigid metal conduit or intermediate
metal conduit.

Entrance
Room

A
space in which the joining of inter- or intra-building telecommunications
or networking backbone facilities takes place. An entrance room may
also serve as an equipment room.

Equipment
Room

An
enclosed area housing telecommunications and network equipment, distinguished
from the telecommunications or wiring closet by its increased complexity
and presence of active equipment.

EPDM

Ethylene-propylene-diene
monomer rubber. A material with good insulating properties.

EPR

Ethylene-propylene
copolymer rubber. A material with good insulating properties.

Ethernet

A local area
network (LAN) protocol defined in the IEEE 802.3 standard in which
computers access the network through a Carrier Sense Multiple Access
/ Collision Detect (CSMA/CD) protocol.

Top


F

f

Frequency

Farad

A
unit of capacitance that stores one coulomb of electrical charge when
one volt of electrical pressure is applied.

Far
End Cross Talk (FEXT)

Crosstalk
that is measured on the quiet line at the opposite end as the source
of energy on the active line. FEXT is not typically measured in cabling,
with Near End Cross Talk (NEXT) being the preferred crosstalk measurement.

Fast
Ethernet

Ethernet
standard supporting 100 Mbps operation.

FCC

Federal
Communications Commission.

FCS

Frame
Check Sequence. Error detection field.

FDDI

Fiber
Distributed Data Interface. An ANSI Standard (ANSI X3T12) for a 100
Mbps token passing network based on fiber-optic (FDDI) and twisted-pair
(CDDI) cabling.

Feeder
Cable

In
a CATV system, the transmission cable from the head end (signal pickup)
to the trunk amplifier. Also called a trunk cable.

FEP

Fluorinated
ethylene propylene. A thermoplastic with excellent dielectric properties
which is often used as insulation in fire rated cables.

FEXT

see
Far End Cross Talk

Fiber
Optics

The
technology in which communication signals in the form of modulated
light beams are transmitted over a glass fiber transmission medium.
Fiber optic technology offers high bandwidth, small space needs and
protection from electromagnetic interference, eavesdropping and radioactivity.

Fifty-pin
Connector

Commonly
referred to as a Telco, CHAMP, or blue ribbon connector, this connector
is used on Ethernet 10Base-T hubs as an alternate twisted-pair segment
connection method. The 50-pin connector connects to 25-pair cables,
which are frequently used in telephone wiring systems and which typically
meet Category 3 specifications.

Fillers

Nonconducting
components cabled with the insulated conductors or optical fibers
to impart roundness, flexibility, tensile strength, or a combination
of all three.

Floating

Refers
to a circuit that has no connection to ground.

FOIRL

Fiber
Optic Inter-Repeater Link. An Ethernet fiber optic connection method
intended for connection of repeaters.

Frequency

The
number of times a periodic action occurs in a unit of time. Expressed
in hertz (abbreviated Hz). One hertz equals one cycle per second.

Frequency
Division Multiplexing (FDM)

A
technique for combining many signals on a single circuit by dividing
the available transmission bandwidth by frequency into narrower bands,
each used for a separate communication channel.

Frequency
Modulation (FM)

One
of three basic methods (see also Amplitude and Phase Modulation) of
adding information to a sine wave signal in which its frequency is
varied to impose information on it.

Frequency
Response

The
range of frequencies over which a device operates as expected.

FTP

see
Screened Twisted Pair (ScTP) cable

Full
Duplex Transmission

Data transmission
over a circuit capable of transmitting in both directions simultaneously.

Top


G

G

Green

Gbps

Gigabits
per second.

Gig

A
prefix meaning one billion

GigaHertz
(GHz)

One
billion hertz.

GIPOF

Graded
Index Plastic Optical Fiber

Graded
Index Fiber

A
multimode fiber optic cable design in which the index of refraction
of the core is lower toward the outside of the core and progressively
increases toward the center of the core, thereby reducing modal dispersion
of the signal.

Ground

A
common point of zero potential such as a metal chassis or ground rod.

Ground
Loop

A condition
where an unintended connection to ground is made through an interfering
electrical conductor.

Top


H

Half
Duplex Transmission

Data
transmission over a circuit capable of transmitting in either direction,
but not simultaneously.

HC

see
Horizontal Cross Connect.

Head
end

The
equipment in a cable system which receives the various program source
signals, processes them, and retransmits them to subscribers.

Headroom

The
amount by which a cable ACR exceeds 10dB.

Hertz

The
unit of frequency, one cycle per second (abbreviated Hz).

HF

High
Frequency

Home
Run

A
cable run that connects a user outlet directly with the telecommunications
or wiring closet, with no intermediate splices, bridges, taps, or
other connections.

Horizontal
Cabling, Horizontal Wiring

The
portion of the cabling system that extends from the work area outlet
to the horizontal cross connect in the telecommunications or wiring
closet.

Horizontal
Cross Connect

A
cross connect of horizontal cabling to other cabling, e.g. horizontal,
backbone, or equipment.

Host

Computer
that offers services on a network.

Hub

A
hardware device that contains multiple independent but connected modules
of network and internetworking equipment. Hubs can be active (where
they repeat signals set to them) or passive (where they do not repeat
but merely split signals sent through them). Hub may also refer to
a repeater, bridge, switch, router, or any combination of these.

HVAC

Heating,
ventilation, and air conditioning system.

Hybrid
Cable

An
assembly of two or more cables (of the same or different types or
categories) covered by one overall sheath.

Hypalon

A Dupont trade
name for a synthetic rubber (chlorosulfonated polyethylene) used
as insulating and jacketing material for cabling.

Top


I

I

Symbol
used to designate current.

IC

see
Intermediate Cross Connect.

ICE

Insulated
Cable Engineers Association

ICS

IBM
Cabling System

IDC

Insulation
Displacement Contact/Connector

IDF

Intermediate
Distribution Frame. This is usually located on each floor within a
building. It is tied directly to the Main Distribution Frame via cables.

IEC

International
Electro technical Commission

IEEE

Institute
of Electrical and Electronics Engineers. A professional organization
and standards body. The IEEE Project 802 is the group within IEEE
responsible for LAN technology standards.

IEEE
802.1

The
IEEE standards committee defining High Level Interfaces, Network Management,
Internetworking, and other issues common across LAN technologies.

IEEE
802.2

The
IEEE standards committee defining Logical Link Control (LLC).

IEEE
802.3

The
IEEE standards committee defining Ethernet networks.

IEEE
802.5

The
IEEE standards committee defining Token-Ring standards.

Impedance

A
unit of measure, expressed in Ohms, of the total opposition (resistance,
capacitance and inductance) offered to the flow of an alternating
current.

Impedance
Match

A
condition where the impedance of a particular circuit cable or component
is the same as the impedance of the circuit, cable, or device to which
it is connected.

Impedance
Matching Transformer

A
transformer designed to match the impedance of one circuit to another.

Index
of Refraction

The
ratio of light velocity in a vacuum to its velocity in a given transmission
medium.

Infrastructure,
Telecommunications

A
collection of those telecommunications components, excluding equipment,
that together provide the basic support for the distribution of all
information within a building or campus.

Interconnection

A
connection scheme that provides for the direct connection of a cable
to another cable or to an equipment cable without a patch cord or
jumper.

Intermediate
Cross Connect

A
cross-connect between 1st level and 2nd level backbone cabling.

Injection
Laser Diode

A
semiconductor laser in which the lasing occurs at the junction of
n-type and p-type semiconductor materials.

Insertion
Loss

A
measure of the attenuation of a device by determining the output of
a system before and after the device is inserted into the system.
For example, a connector causes insertion loss across the interconnection
(in comparison to a continuous cable with no interconnection).

ISDN

Integrated
Services Digital Network

ISO

International
Standards Organization

Isolated
Ground

A
separate ground conductor which is insulated from the equipment or
building ground.

Isolation

The
ability of a circuit or component to reject interference.

Insulation

A
material which is nonconductive to the flow of electrical current.

Interference

Undesirable
signals which interfere with the normal operation of electronic equipment
or electronic transmission.

Isochronous

Signals
which are dependent on some uniform timing or carry their own timing
information imbedded as part of the signal. Voice and video signals
are isochronous signals, but data transfer is generally not.

ITU

International
Telecommunications Union. An international organization that develops
communications standards.

Top


J

Jabber

Term
used with Ethernet to describe the act of continuously sending data.
A jabbering station is one whose circuitry or logic has failed, and
which has locked up a network channel with its incessant transmission.

Jack

A
female connector.

Jacket

The
outer protective covering of a cable.

Jitter

The
slight movement of a transmission signal in time or phase that can
introduce errors and loss of synchronization. More jitter will be
encountered with longer cables, cables with higher attenuation, and
signals at higher data rates. Also, called phase jitter, timing distortion,
or intersymbol interference.

Jumper

An assembly
of twisted pairs without connectors used to used to join telecommunications
circuits at the cross connect. Similar to a patch cable (which has
connectors).

Top


K

Keying

The mechanical
feature of a connector system that guarantees correct orientation
of a connection, or prevents the connection to a jack, or to an
optical fiber adapter, of the same type intended for another purpose.

Top


L

L

Symbol
used to designate inductance.

LAN

Local
Area Network

LAN
Adapter

see
Network Interface Card

Laser

Light
Amplification by Stimulated Emission of Radiation. A device which
produces light with a narrow spectral width. Used in fiber optic communication
systems, usually single mode, where high capacity and low attenuation
are required.

LAT

Local
Access and Transport Area.

Lay

The
axial distance required for one cabled conductor or conductor strand
to complete one revolution about the axis around which it is cabled.

Lay
Direction

The
direction of the progressing spiral twist in while looking along the
axis of the cable away from the observer. The lay direction can be
either “left” or “right”.

LCL

see
Longitudinal Conversion Loss

LCTL

see
Longitudinal Conversion Transfer Loss

Leakage

An
undesirable passage of current over the surface of or through a connector.

Leased
Line

A
private telephone line rented for the exclusive use of a leasing customer,
without interchange switching arrangements.

LED

see
Light Emitting Diode.

LF

Low
frequency.

Light
Emitting Diode

A
semiconductor diode which emits incoherent light when a current is
passed through it. Used as a light source in fiber optic transmission.

Link

A
transmission path between two points not including terminal equipment,
work area cables, or equipment cables.

Listed

Equipment
included on a list published by an organization, acceptable to the
authority having jurisdiction, that maintains periodic inspection
of production of listed equipment, and whose listing states either
that the equipment or material meets appropriate standards or has
been tested and found suitable for use in a specified manner.

Lobe

An
arm of a Token-Ring which extends from a Multistation Access Unit
(MSAU) to a workstation adapter.

LocalTalk

A
low-speed form of LAN data link technology, part of Apple Computer’s
AppleTalk networking scheme, that uses a carrier sense multiple access
with collision avoidance (CSMA/CA) form of medium access control.
Supports transmission at 230 Kbps.

Longitudinal
Conversion Loss (LCL)

Also
called near-end unbalance attenuation, measures cable balance by comparing
the signal appearing across the pair to the signal applied between
ground and the pair, where the applied signal and the across pair
signal are at the same end of the cable.

Longitudinal
Conversion Transfer Loss (LCTL)

Also
called far-end unbalance attenuation, measures cable balance by the
comparison of the signal appearing across the pair to the signal between
ground and the pair, where the applied signal is at the opposite end
of the cable from where the across pair signal is measured.

Loopback

A
type of diagnostic test in which a transmitted signal is returned
to the sending device after passing through a data communications
link or network. This test allows the comparison of a returned signal
with the transmitted signal.

Loss

The
portion of energy applied to a system that is dissipated and performs
no useful work.

Lossy

Having poor
efficiency.

Top


M

M

Mutual
Inductance

m

Milliampere
(one thousandth of an ampere)

MAC

see
Medium Access Control

Main
Cross Connect

A
cross connect for first level backbone cables, entrance cables, and
equipment cables. The main cross connect is at the top level of the
premises cabling tree.

Manchester
Coding

A
method of LAN signal encoding in which each bit time that represents
a data bit has a transition in the middle of the bit time. Used with
10 Mbps Ethernet (10Base2, 10Base5, 10Base-F, & 10Base-T), and
Token-Ring LANs.

Material
Dispersion

Dispersion
that results from each wavelength traveling at a different speed than
other wavelengths through an optical fiber. Also called “chromatic
dispersion”.

MAU

Media
Attachment Unit. The transceiver in Ethernet networks. Also a common
name for the MSAU (Multi-station Access Unit) in Token-Ring networks.

Mbaud

Megabaud.
One million baud.

Mbps

Megabits
per second.

MC

see
Main Cross Connect

MDF

Main
Distribution Frame

MDI

see
Media Dependent Interface

Medi

Wire,
cable, or conductors used for transmission of signals.

Media
Filter

An
impedance matching component used in Token-Ring networks to transform
the 100 ohm impedance of UTP cabling to the 150 ohm impedance of media
interface connections.

Medium
Access Control (MAC)

A
mechanism operating at the data link layer of local area networks
which manages access to the communications channel (medium).

Medium
Dependent Interface (MDI)

In
Ethernet, the connector used to make the mechanical and electrical
interface between a transceiver and a media segment. An 8-pin RJ-45
connector is the MDI for the 10Base-T, 100Base-TX, 100Base-T2, 100Base-T4,
and 1000Base-T media systems.

Medium
Independent Interface (MII)

Used
with 100 Mbps Ethernet systems to attach MAC level hardware to a variety
of physical media systems. Similar to the AUI interface used with
10 Mbps Ethernet systems. An MII provides a 40-pin connection to outboard
transceivers (also called PHY devices).

Meg

Prefix
meaning one million.

Megahertz
(MHz)

One
million hertz.

MIC

Medium
Interface Connector. Duplex fiber optic connector used with Fiber
Distributed Data Interface (FDDI) networks.

Micro

Prefix
meaning one millionth.

Microfarad

One
millionth of a farad. Abbreviated µF (less commonly µfd, mf, and mfd).

Micron

One
millionth of a meter. Abbreviated µm.

Midsplit
Broadband

A
broadcast network configuration in which the cable is divided into
two channels, each using a different range of frequencies. One channel
is used to transmit signals and the other is used to receive.

MII

see
Medium Independent Interface.

Mil

Unit
of length equal to one thousandth of an inch (0.001 inch).

Milli

Prefix
meaning one thousandth.

Mixing
Segment

Ethernet
term used in IEEE 802.3 standards to describe a segment that may have
more than two MDI connections.

MMF

set
Multimode Fiber

Modal
Dispersion

Dispersion
that results from the different transit lengths of different propagating
modes in a multimode optical fiber.

Mode

A
single electromagnetic wave traveling in an optical fiber.

Mode
Field Diameter

The
diameter of optical energy in a single mode fiber. Because the mode-field
diameter is larger than the core diameter, it replaces core diameter
as a practical parameter.

Modem

A
device that implements “modulator-demodulator” functions
to convert between digital data and analog signals.

Modular
Jack

The
equipment mounted half of a modular interconnection. Typically a female
connector. A modular jack may be keyed or unkeyed and may have six
or eight contact positions, but not all the positions need to be equipped
with jack contacts.

Modular
Plug

The
cable mounted half of a modular interconnection. Typically a male
connector. A modular plug may be keyed or unkeyed and may have six
or eight contact positions, but not all the positions need to be equipped
with contacts.

Modulation

Altering
the characteristics of a carrier wave to convey information. Modulation
techniques include amplitude, frequency, phase, plus many other forms
of digital encoding.

MSAU

Multi-station
Access Unit. Device used to interconnect lobe cables from stations
on a Token-Ring network.

MT-RJ

Proposal
for a new duplex fiber optic connector standard from AMP/Siecor.

Multimode
Fiber

A
fiber optic cable which supports the propagation of multiple modes.
Multimode fiber may have a typical core diameter of 50 to 100 µm with
a refractive index that is graded or stepped. It allows the use of
inexpensive LED light sources and connector alignment and coupling
is less critical than single mode fiber. Distances of transmission
and transmission bandwidth are less than with single mode fiber due
to dispersion.

Mutual
Capacitance

Capacitance
between two conductors when all other conductors are connected together.

mV

Millivolt
(one thousandth of a volt)

mW

Milliwatt
(one thousandth of a watt)

Mylar

Dupont
trademark for polyethylene terephtalete (polyester) film.

N

N

see
Numerical Aperture

N
connector

A
coaxial connector used for Ethernet 10Base5 thick coax segments.

Nanometer
(nm)

One
billionth of a meter.

Nanosecond
(ns)

Butadiene-acrylonitrile
copolymer rubber, a material with good oil and chemical resistance.

NBR

One
billionth of a second.

Near-End
Crosstalk

Crosstalk
between two twisted pairs measured at the same end of the cable as
the disturbing signal source. NEXT is the measurement of interest
for crosstalk specifications.

NEC

National
Electrical Code.

NEM

National
Electrical Manufacturers Association.

Neoprene

A
synthetic rubber with good resistance to oil, chemical, and flame.
Also called polychloroprene.

Network

An
interconnection of computer systems, terminals or data communications
facilities.

Network
Interface Card

A
circuit board installed in a computing device used to attach the device
to a network. A NIC performs the hardware functions that are required
to provide a computing device with physical communications capabilities.
Also Network Interface Unit (NIU).

NEXT

see
Near-End Crosstalk.

NFP

National
Fire Protection Association

Nibble

One
half byte.

NIC

see
Network Interface Card.

NIR

Near-end
Crosstalk-to-Insertion Loss Ratio

Node

End
point of a network connection. Nodes include any device connected
to a network such as file servers, printers, or workstations.

Noise

In
a cable or circuit, any extraneous signal which interferes with the
desired signal.

Nomex

Dupont
trademark for a temperature-resistant, flame retardant nylon.

NRZ

Non
Return to Zero.

NRZI

Non
Return to Zero Inverted.

Numerical
Aperture (NA)

The
“light gathering ability” of an optical fiber, defining
the maximum angle to the fiber axis at which light will be accepted
and propagated.

NVP

Nominal
Velocity of Propagation. The speed a signal propagates through a cable
expressed as a decimal fraction of the speed of light in a vacuum.

Nylon

An abrasion
resistant thermoplastic with good chemical resistance.

Top

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

Top


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-

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.

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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”.

TI

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
Medi

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
1

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
2

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
6

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
9

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.

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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.

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V

V

Symbol
for Volt.

V

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
Are

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

Top


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