Like most industries, cables uses terminology, references and abbreviations that are unfamiliar to many people. This glossary explains the main terms that are used, in alphabetical order.
A B C D E F G H I J L M N O P Q R S T U V W X
A
Alternating Current (AC)
A type of electrical current, in which the direction of the flow of electrons switches back and forth at regular intervals or cycles.
Alternating Current (AC) Resistance
Cable AC resistance, usually measured in ohms/km, is the resistance a material has to the flow of alternating current (AC). It is used for circuit rating calculations. AC resistance is different from direct current (DC) resistance, which is constant.
Ambient Temperature
Ambient temperature is the average temperature of the air in a given environment. It’s also known as the ordinary or baseline temperature.
American Wire Gauge (AWG)
An American logarithmic stepped standardized wire gauge system for the diameters of round, solid, nonferrous, electrically conducting wire.[1] The cross-sectional area of each gauge is an important factor for determining its current-carrying capacity.
Ampacity
A term for the maximum current carrying capacity, in amperes or amps, of a particular device
Ampere (Amp)
The unit of current flowing through one ohm of resistance at one volt potential.
Anneal
A process of heating and then cooling a material, such as steel or copper, usually for softening and making less brittle, for improved flex-life.
Aramid Yarn
A strong synthetic material often used in cable construction to create tensile strength.
Armour
A braid or wrapping of metal, or non-metallic material used to protect a cable from mechanical stress. Usually placed under the outer sheath.
Attachment cable
The cable between a wall socket and active equipment, usually a computer or data terminal equipment.
Attenuation
Power loss in an electrical system. For cables, this is generally written as db per unit length, usually a km.
Attenuator
A passive electronic device that reduces the power of a signal without appreciably distorting its waveform.
B
Backbone Cable
The network cable which connects across various rooms and communication panels, normally forming the longest cable run
Balanced Cable
Balanced cables have two conductor wires and a ground (earth) wire. The extra conductor makes it possible to significantly reduce noise in an audio signal.
Balanced Pair
A balanced line or balanced signal pair of cables consist of two conductors of the same type, both of which have equal impedances along their lengths, to ground (earth) and to other circuits. The main advantage is good noise reduction when fed into a transformer or amplifier.
Balun
A device used to convert an unbalanced circuit to a balanced circuit.
Bandwidth
The maximum amount of data that can be transmitted over a network within a given time frame. It’s often measured in megabits per second (Mbps) or gigabits per second (Gbps).
Baseband
A type of signal that can be analog or digital, and is used to transmit data and synchronize components.
Bedding
A layer of fibrous material like jute or hessian tape. It is used to protect cores against corrosion and from mechanical damage due to armouring.
Bps
Bits per second. A unit of measure that describes the rate of data transmission.
Braiding
Interwoven textile or metallic filaments forming a tubular flexible structure around a cable.
C
Cable Assembly
A finished cable with appropriate fixings.
Cable Core
The metal conductor lying under the outer protective coverings of a cable.
Cable Drum
A (wooden) cylinder of various sizes. Cable is wound round during manufacture, and used for storage, transportation and installation.
Capacitance
The ability of a cable to store electric charge. It is measured in farad to explain the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities.
Coaxial Cable
Coaxial cable, or coax is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material). Many coaxial cables also have a protective outer sheath or jacket.
Common-mode
The mode where the voltage of both conductors of a pair, relative to ground potential is equal and in phase.
Composite Cable
A cable containing more than one gauge size or a variety of circuit types, e.g. pairs, triples, quads, coaxials.
Concentric Stranding
A conductor with a central wire or core surrounded by layers of spiral wound wires.
Conductivity
The ability of a material to carry an electrical current. Usually expressed as a percentage of copper conductivity – copper being one hundred (100%) percent.
Conductor
A material (metal) capable of carrying electric current. The most common metals for wire and cable use are aluminium and copper.
Conductor Resistance
The ratio of the potential difference across to the current flowing through a conductor. Usually expressed in ohms/km. Required for voltage drop and current rating calculations. (See also Resistance).
Connector
A device used to physically and electrically connect two or more conductors.
Core
The central component(s), usually copper or aluminium, which other materials are applied on top of, such as a shield, sheath, or armour.
Core Identification
The method of distinguishing between multiple cores, either with a colour or a number.
Crimp Termination
A wire termination that is attached by compression to the conductor.
Cross sectional area (CSA)
The area of the cut surface of the conductor of a cable cut at right angles to the length of the cable.
Crosstalk
Electrical interference between adjacent conductors.
Current Carrying Capacity
This is the maximum allowable continuous current carrying capacity of a conductor without exceeding either the insulation or jacket material limitations. (See also Ampacity)
D
Dielectric
An insulating material between conductors in a cable.
Dielectric Strength
The voltage which an insulating material can withstand before breaking down.
Differential-mode
The mode of transmission where the voltage is equal and in opposite phase on each conductor relative to ground potential.
Direct Burial Cable
A cable installed directly in the ground without a conduit.
Direct Current (DC)
Electrical current that flows in one direction only.
Direct Current Resistance
A measure (in Ohms) of how much a material or component resists the flow of direct current.
Direction of Lay
The direction, clockwise or anti-clockwise, of conductor(s) when looking down a cable length.
Dissipation
The loss of energy, as the production of waste heat in a circuit.
Drain Wire
An uninsulated wire usually placed directly underneath an electrical contact with a grounded shield, used for making ground connections.
Duct
A trough used for carrying electrical conductors for mechanical protection
E
Earth Continuity Conductor
A conductor used to connect equipment (or the earth circuit of a wiring system) to a grounding electrode.
Electrical Length
The length of cable multiplied by the relative propagation velocity.
Electrical Screen
A metallic shield which isolates a device from external fields.
Electromagnetic Disturbance
The disturbance of a signal by a superimposed electromagnetic field.
EL-FEXT (Equal Level of FEXT)
Calculation that normalises the results of Far End Cross Talk (FEXT) as it takes attenuation into account. It is calculated by subtracting attenuation of interfering pairs from the FEXT.
Ethylene Propylene Diene Monomer (EPDM)
An ozone resistant rubber consisting mainly of ethylene propylene diene terpolymer.
Ethylene Propylene Rubber (EPR)
An ozone resistant rubber consisting mainly of ethylene propylene copolymer.
F
Fault current
The maximum electrical current that flows through a circuit during an electrical fault condition prior to the activation of a current limiting device.
Fire Integrity
The amount of time a cable can be exposed to a flame and continue to function.
Fire Resistance
The ability of a cable to continue to function and transmit power when exposed to extreme heat during a fire
Flame Retardance
The ability of a cable to restrict the spread of flames during a fire.
Foam Filled
The cellular structured insulation typically found in coaxial cable which acts as a dielectric.
Foil
The film of metal or composite polymer used as a screen in cable production.
Foiled Twisted Pairs Cable (FTP)
A cable containing multiple twisted pairs of wire wrapped in a foil screen. Also known as Screened Twisted Pairs.
Frequency
The number of cycles which occur in one second. Frequency is measured in Hertz.
FTP
Foiled Twisted Pair. Cat 5e FTP Cable contains an Aluminium Foil (Al-Foil) screen, which provides protection against external electromagnetic interference or cross talk.
Full duplex
Allows data to travel in two directions at once. One pair of wires transmit and one pair receive simultaneously.
G
Grounding Conductor
A conductor used to connect equipment (or the earth circuit of a wiring system) to a grounding electrode.
GSWB
Galvanised Steel Wire Braid.
H
Halogen
A particular group of elements with similar bonding properties, consisting of flourine, chlorine, bromine and iodine. NOTE: Halogen gases are poisonous when inhaled.
Heat Endurance
Cables that are designed to withstand extreme temperatures – up to 260°C.
Heat Resistance
The property of a material to resist the deteriorating effects of high temperatures.
Helix
A spiral winding.
Hertz (Hz)
The term to denote cycles-per-second as an indication of frequency.
HOFR
Stands for Heat and Oil Resistant, Flame Retardant cables
Horizontal Cabling
The data cables connecting wall outlets to data cabinets in a data room. This includes Cat 5E and Cat 6.
I
Impedance
The total opposition that a circuit offers to the flow of a current at a particular frequency.
Inductance
The property of wire which stores electrical current in a magnetic field around the wire. This can be intensified by coiling the wire.
Insulation
A material having high resistance to the flow of electric current. Often called a dielectric.
Insulation Resistance
That property of an insulating material which resists electrical current flow through the insulating material when a potential difference is applied.
Interference
Undesired electrical or electromagnetic signal induced into a conductor.
J
Jacket
The material, usually an extruded plastic or elastomer, applied outermost to a wire or cable to provide mechanical and environmental protection. (See also Sheath).
Jumper
A short length of conductor used to make a connection between terminals or around a break in a circuit.
L
LAN
A Local Area Network is a computer network that covers a small area.
Lay
The length measured along the axis of a wire or cable of one complete helix of a strand or conductor.
Loss Factor
The dissipation multiplied by the dielectric constant of an insulation material.
LSF
Low Smoke and Fume cables usually made with a modified PVC compound to produce less smoke.
LSZH
Low Smoke Zero Halogen cable considerably reduces the amount of toxic and corrosive gas emitted during combustion. When burned, it emits a less dense smoke that releases at a lower rate.
M
MAN
A Metropolitan Area Network is a data network designed for a town or city.
Marker Tape
A tape, printed with the manufacturer’s name, and other relevant information and laid parallel to the conductors in a cable under the outer sheath.
Mechanical Splice
A semi-permanent joint created by mechanical means, which ensures the electrical/optical continuity of conductors or fibres.
Messenger Wire
A longitudinal wire supporting the weight and enhancing the tensile strength of a suspended cable.
Minimum Bending Radius
The radius to which a copper or fibre cable can be bent before the risk of breakage or the degradation of performance occurs.
Miss-Wire (see Crossed Pairs)
Happens when single wires in a UTP cable are attached to the connector in the wrong sequence.
Mode
A single wave that travels in a Fibre Optic Cable.
Moisture Absorption
The amount of moisture, in percentage, that an insulation or a jacket will absorb under specified conditions.
Multiconductor
More than one conductor within a single cable complex.
Multifibre Cable
An optical fibre cable containing two or more fibres.
Multimode Fibre
Fibre with a comparatively wide optical core, permitting several light modes to pass at once.
Mutual Capacitance
Capacitance between two conductors when all other conductors are connected together.
N
N Connector
An electrical connector designed to join coaxial cables.
NBR
Nitrile Butadiene Rubber, which has good oil and chemical resistance.
Neoprene
A polychloroprene synthetic rubber with excellent flame retarding and abrasion resisting qualities used as a jacketing material. (Also see Polychloroprene).
Neutral Conductor
The wire in a two-wire AC electrical system that carries the return current.
NEXT
Near End Cross Talk. Signal interference between two neighbouring twisted pairs.
NIR
Near End Cross Talk (see NEXT) to Insertion loss Ratio.
Node
An electronic device attached to a network, such as a printer or computer.
Nominal Thickness
The specified, indicated, or named thickness of an extruded layer in a wire or cable.
Numerical Aperture
The “light gathering ability” of a fibre, defining the maximum angle to the fibre axis at which light will be accepted and propagated through the fibre.
Numerical Aperture
The angle at which an optical fibre will gather light and spread down the core.
O
Ohm
The unit of electrical resistance. It is the value of resistance through which a potential difference of one volt will maintain a current of one ampere.
Ohm’s Law
Stated V=IR, I=V/R or R=V/I, the current I in a circuit is directly proportional to the voltage V, and inversely proportional to the resistance R.
Operating Temperature
The range of temperatures between which cables will continue to function acceptably.
Optical Fibre
Translucent fibre which can transmit beams of laser light.
Optical Fibre Cable
A cable in which the transmission elements are optical fibres.
OSI
Open System Interconnection. This is the network rule book – a standard for worldwide communications that defines the networking framework for implementing protocols in seven layers. The seven layers include the Physical layer and the Application layer.
OTDR
Optical Time Domain Reflectometer. An optoelectronic instrument that sends pulses into optical fibre to measure length and find faults in the cable.
Outer Protection
The outer layer of a cable intended to enhance the mechanical protection from external factors.
Outside Diameter
The length of a straight line passing through the centre of a cable and connecting two points on the circumference.
Ovality
Distortion of pipe or round tube from its normal, round shape to an oval shape.
Overhead (Aerial) Cable
A cable suspended in the air on poles or other overhead structures
Oxygen Index (OI)
Percentage of Oxygen required to support combustion.
P
Packet
A string of bits containing command information, destination and source addresses and data. Messages are broken down into packets for transmission across a network.
Partial Discharge Test
A test to measure the electrical discharge or spark that bridges a portion of the insulation between two conducting electrodes. Partial discharge can occur at any location within the insulation system (between the two electrodes) where the electric field strength exceeds the breakdown strength of that portion of the insulating material.
Patch Lead
Also known as a Patch Cable or Patch Cord, this is the cable that connects the network panel and the active switch or hub. It also runs from the wall outlet to the electrical appliance in structured cabling networks – it has flexible copper stranded conductors so it portable and suitable for domestic and office environments.
PCM
Pulse Code Modulation. A sampling technique used to digitise analogue signals.
Physical layer
A physical layer is the first level in the seven-layer OSI model of computer networking. This layer is responsible for the transmission of signals between computers
Pigtail
A short length of optical fibre or cable that has a connector installed on one end.
Polychloroprene (PCP)
A synthetic rubber with excellent flame retarding and abrasion resisting qualities used as a jacketing material. (Also see Neoprene).
Polyethylene (PE)
A thermoplastic material composed of polymers of ethylene. It has excellent dielectric properties.
Polyvinyl Chloride (PVC)
A family of vinyl compounds widely used as insulation on low voltage applications and jacketing for many types of cables.
POTS
Plain Old Telephone Service is a term used when referring to the basic telephone network that exists across much of the world.
Power Rating
The maximum continuous input power when the cable is terminated with its nominal impedance.
Premises cabling
Cabling for voice, data and video transmission throughout a given building.
Primary coating
The plastic coating applied directly to the cladding surface during manufacture of optical fibres to preserve the integrity of the surface.
Propagation delay
The amount of time it takes for a number of bytes to travel from the input to the output of a device.
Propagation Time
Time required for a wave to travel between two points on a transmission line.
Protocol
A protocol is an agreed standard that controls or enables the transfer of data between two devices.
PSACR
The Power Sum Attenuation to Cross Talk Ratio
PSELFEXT
Power Sum Equal Level Far End Cross (X) Talk. In a four-pair cable, PSELFEXT measures the effect of cross talk from 3 pairs on the remaining pair.
PS-ELFEXT (Power Sum Equal Level FEXT)
Sum of EL-FEXT, which is the calculation that normalises the results of Far End Cross Talk (FEXT) as it takes attenuation into account. It is calculated by subtracting attenuation of interfering pairs from the FEXT.
PSNEXT
Power Sum Near End Cross Talk. In a four-pair cable, PSNEXT refers to the crosstalk affecting one pair from the three other pairs.
PS-NEXT (Power Sum NEXT)
Power Sum NEXT (PS-NEXT) is the sum of the total NEXT power coupled to a wire pair from all other adjacent pairs.
PSTN
Public Switched Telephone Networks or PSTN is the term used to describe the international telephone system.
Pull Strength
The pulling force that can be safely applied to a cable without damage.
Pulling tension
The maximum pulling force that can be applied to data fibre optic cable without affecting its electrical characteristics and network performance.
Q
Quad
A term used to describe a cable consisting of four separately insulated conductors twisted together.
R
Reflected Wave
A wave that travels from the discontinuity in a transmission line in an opposite direction to that of the incident wave.
Reflection
The return of electromagnetic energy that takes place when components are mismatched in network cabling. Reflections are known to cause data errors.
Refraction
The bending of light as it passes from one medium to another.
Repeater
A device – usually a network hub or switch – that receives and retransmits data at a higher level/power or to the other side of an obstruction. The signal can travel over longer distances.
Resistance
The ratio of the potential difference across to the current flowing through a conductor. Usually expressed in ohms/km. This parameter is required for voltage drop and current rating calculations.(See also Conductor Resistance).
Resistor
A two-terminal electrical or electronic component that resists an electrical current by producing a voltage drop between its terminals in accordance with Ohm’s Law.
Return Loss
The ratio, at the junction of a transmission line and a terminating impedance or other discontinuity, of the amplitude of the reflected wave to the amplitude of the incident wave. The return loss value describes the reduction in the amplitude of the reflected energy, as compared to the forward energy.
Reversed Pairs (or Crossed Pairs)
A common fault where the single wires in a pair have been reversed.
RFI
Radio Frequency Interference – unwanted interference that affects an electrical circuit.
Ring Network
A Ring Network is a network topology where all nodes are connected in a circular formation. Data travels from node to node.
Riser Cable
Indoor cables made for between floor applications.
RX
An abbreviation of ‘receive’.
S
Screen
The conducting layer of a cable which has the function of controlling the electric field within the cable core or element.
Screened Twisted Pairs Cable (STP)
A cable where each twisted pair is individually screened. It may also have an additional overall screen.
Screening Effectiveness
The ratio of the power inside a cable to the total radiated power outside.
Secondary Coating
A coating applied directly to the primary coating of fibres to reinforce the protection of the optical fibre during handling and cabling. Also known as a buffer.
Secondary Insulation
Any extremely high resistance material which is placed over primary insulation to protect it from abrasion.
Semi Rigid Cable
A cable containing a flexible inner core and a relatively inflexible sheathing material, such as a metallic tube.
Semi-Conductor
A material possessing electrical conductivity that falls somewhere between that of conductors and insulators.
Semi-Flexible Cable
A cable not intended for applications requiring repeated flexing in service but bending or forming is possible during installation.
Sheath
The material, usually an extruded plastic or elastomer, applied to the outside of a wire or cable to provide mechanical and environmental protection.(See also Jacket).
Shield
A metallic layer of tape, braid or spiral wrapped wire construction (commonly aluminium or copper) with the primary purpose of preventing electrostatic or electromagnetic interference between adjacent wires and external sources.
Shield Coverage Percentage
Percentage of the surface are of a cable core surface area which is covered by the shield.
Shielded
Cable with metal shielding to reduce electromagnetic interference.
Single Mode Fibre
A fibre with a small core, usually between 2 and 9 microns that can only support one wavelength.
Skew
The difference in arrival time of data transmitted by two adjacent cables simultaneously.
SNMP
Simple Network Management Protocol. A protocol used in network management systems to monitor network-attached devices
Socket/Jack
A connector for attachment to the fixed end of a cable.
SOHO
An abbreviation of Small Office Home Office, SOHO refers to a small/home office environment. It often mixes voice, data and video on the same cables.
Solid Dielectric Cables
Cables where the space between the inner conductor and outer conductor is substantially filled by solid plastic dielectric.
Spark Test
A test designed to locate flaws in an insulated wire by application of an electrical potential across the material for a very short period of time while the wire is drawn through an electrode field.
Spike Test
A Spike Test is a test specifically designed to prove that the screen of a cable can withstand a full specified fault current for a defined period. It simulates the accidental “spiking” of a live cable installation and ensures that the circuit protection will operate and the circuit fails to safety.
Splice
A connection of two or more conductors or cables to provide good mechanical strength as well as good conductivity.
Split Pairs
A Split Pair is a common wiring error, where a connection is made using the single wires from two different pairs. The benefits brought about by twisting the pairs (e.g. interference) in the first place are lost.
Static Bending Radius
The smallest radius an installed cable can be bent once without damaging its transmission characteristics.
STP
Shielded Twisted Pair, with metal shielding over each individual pair of copper wires.
Strand
A single uninsulated wire.
Stranded Conductor
A conductor made of individual wires twisted together.
Strength Member
An element that mechanically reinforces a cable, especially for tension, compression or bending.
Structured cabling
Fixed data and telecommunications cabling used in a building.
SWA
Steel Wire Armour, as opposed to Aluminium Wire Armour (AWA) cables.
Symmetrical Pair
The assembly of two insulated conductors twisted together. (See also Balanced Pair).
T
TCP
Transmission Control Protocol. A protocol is an agreed standard that controls or enables the transfer of data between two devices. TCP enables two hosts to establish a connection and exchange streams of data.
TCWB
Tinned Copper Wire Braid, a type of cable shielding that protects against electrical interference.
TDR
Time Domain Reflectometer. An electronic instrument used to measure the length of cables to identify flaws.
Temperature Rating
The maximum temperature in °C that a cable can safely continuously operate without loss of its basic properties.
Terminator
A device attached to the end of a cable to reduce signal reflections and unwanted noise.
Thermoplastic Insulation
A material which will soften, flow or distort when subjected to heat and pressure. Examples are PVC (Polyvinyl Chloride) and PE (Polyethylene).
Thermoset Insulation
A material which will not soften, flow or distort when subjected to heat and pressure, e.g. XLPE (cross-linked Polyethylene) and Neoprene.
Tinned Wire
Tin-coated copper wire to make soldering easier and to prevent corrosion.
Topology
Topology can be the physical and the virtual design of a network.
TPE
Thermoplastic Elastomers – a class of plastics that are soft and rubbery, and can be recycled.
Transceiver
A device that can both transmit and receive signals, such as radio waves, light, or digital data.
Transfer Impedance
The ratio of the voltage applied to the input terminals to the current which flows at the output terminals when the output is grounded.
Transmission Line
A specialized cable or other structure designed to conduct electromagnetic waves in a contained manner, to minimise radiation.
Trefoil
A cross-sectional arrangement of cables that minimises electrodynamic forces during fault conditions.
Twisted Pair
A cable composed of two insulated conductors, twisted together without a common covering.
Twisted Pair
Pairs of wires that are twisted together to reduce the amount of electromagnetic interference from external sources and crosstalk between neighbouring pairs.
TX
An abbreviation of ‘transmit’.
U
UN-balanced cable
In an unbalanced cable, a single conductor carries a single unbalanced signal. The outer screen on the cable doubles up as the signal return path. A coax is an example of an un-balanced cable.
Underground Cable
A cable installed in an underground trough or duct system which separates the cable from direct contact with the soil.
Uscreened Twisted Pair Cable (UTP)
Unshielded twisted pair is the most common kind of copper telephone wiring.Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company.
V
Volt (V)
A unit of measurement for electric potential, electromotive force, and electric potential difference. It’s the difference in potential between two points in a conducting wire.
Voltage Drop
The decrease in voltage that occurs in an electrical circuit as current passes through it. It’s caused by the resistance of the wires and other components in the circuit.
Voltage Rating
The highest voltage that can be continuously applied to a wire or cord to conform with standards or specifications.
VoP
Velocity of Propagation. The speed at which an electrical signal passes through a medium. Expressed as a percentage, it is the ratio of a signal’s transmission speed compared to the speed of light in a vacuum.
W
WATT (W)
A measure of electrical power. Watts measure the actual power being used and is calculated by multiplying volts by amps (current)
Wave Length
The distance between positive peaks of a signal. As the frequency increases, and waves get closer together, the wavelength decreases.
X
XLPE
Cross-linked polyethylene – a type of electrical cable commonly used for power transmission and distribution. Made of a thermoset material, it is highly resistant to heat, moisture, and chemicals.
