FAQ: Cable Glossary

Providing definitions for as many cable related terms as we can, across Power, Data, Instrumentation, and Control cable applications and installations.

• Air Spaced Cables

A cable in which air is the essential dielectric material. A spirally wound synthetic filament or spacer may be used to center the conductor.

• Alien Crosstalk

Crosstalk from an adjacent cable or cables.

• Alternating Current Resistance

Electrical resistance (usually ohms/km) of a cable when measured with alternating current. (This will generally be higher than the direct current resistance, and is needed for the purpose of circuit rating calculations.)

• Ambient Temperature

The temperature of any medium surrounding an object.

• American Wire Gauge (AWG)

An American standard system to indicate wire diameter. The smaller the AWG number, the larger the wire diameter.

• Ampacity

The maximum allowable continuous current carrying capacity of a conductor without exceeding either the insulation or jacket material limitations. (See also Current Carrying Capacity).

• Ampere

The unit of current flowing through one ohm of resistance at one volt potential.

• Anneal

To soften and relieve strains in any solid material by heating to just below its melting point and then slowly cooling it. Annealing generally lowers the tensile strength of the material, while improving its flex-life and flexibility.

• Aramid Yarn

Generic name for a tough synthetic material that is often used in cable construction to provide tensile strength.

• Armour

A braid or wrapping of metal, (usually steel), or non-metallic material used to protect a cable from mechanical stress. This is generally placed under the outer sheath.

• Attachment cable

The cable between the wall socket and active equipment - usually a PC or DTE. See Patch Lead.

• Attenuation

The power loss in an electrical system. In cables, this is generally expressed as db per unit length, usually a km.

• Attenuator

An electronic device that reduces the amplitude or power of a signal without distorting its waveform. Attenuators are usually passive devices made from resistors.

• Backbone Cable

A cable used to interconnect buildings.

• Balanced Cable

Cables of which the transmission lines are symmetrical pairs. (See also Symetrical Cable).

• Balanced Pair

The assembly of two insulated conductors twisted together. (See also Symetrical Pair).

• Balun

A device used to convert an unbalanced circuit to a balanced circuit.

• Bandwidth

A measure of the amount of data that can be transmitted via a communications channel.

• Baseband

A type of transmission where data is sent over a single unmultiplexed channel, such as an Ethernet LAN. Baseband transmissions send simultaneous bits of data along the full bandwidth of the transmission channel.

• Bedding

The additional underlying sheath of a cable which protects the cores from mechanical stress.

• 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.

• Bundle

A number of individual cable elements contained within a single jacket or sheath and distinguished from other groups in the same cable.

• Buried cable

A cable installed directly into the earth without the use of a conduit.

• Cable

An insulated group of one or more conductors or optical fibres in twisted or parallel configuration with a protective sheath.

• Cable Assembly

A completed cable and its associated hardware.

• Cable Core

The conductor with its own insulation (and screens if any) lying under the outer protective covering(s) of a cable.

• Cable Drum

A cylinder onto which cable is wound during manufacture, for storage, transportation and installation.

• Capacitance

The ability of a dielectric material between conductors to store electric charge when a difference of potential exists between the conductors. The unit of measurement is the farad, which is the capacitance value that will store a charge of one coulomb when a one-volt potential difference exists between the conductors. In AC, one farad is the capacitance value which will permit one ampere of current when the voltage across the capacitor changes at the rate of one volt per second.

• CATV System

Community antenna television.

• Cladding

A low refractive index material that surrounds the core of an optical fibre causing the transmitted light to travel down the core and protects against surface contaminant scattering.

• Coaxial Cable

A cable consisting of two conductors with a common axis separated by a dielectric.

• 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, eg. pairs, triples, quads, coaxials, etc.

• Concentric Stranding

A conductor consisting of a central wire or core surrounded by one or more layers of helically wound wires.

• Conductivity

The capability 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 capable of carrying electric current. The most common materials for wire and cable applications 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. This parameter is 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 or assembly of components over which other materials are applied, 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

The electrical interference between adjacent conductors.

• Crosstalk

When wires are placed next to each other in parallel (within a cable) there is usually some crosstalk - signal interference between the cables. (see also alien crosstalk).

• CSMA/CD

Carrier Sense Multiple Access with Collision Detection. When a Network Interface Card is ready to transmit data, it first checks for a signal within the cable. If no signal is present it will begin transmission, but if there is a signal the transmission is delayed. If two NICs detect an idle cable simultaneously a collision may occur. The two NICs involved will experience a time delay before bring able to transmit again.

• 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)

• Dielectric

An insulating material between conductors in a cable.

• Dielectric Strength

The voltage which an insulating material can withstand before breakdown occurs.

• 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 earth without a conduit.

• Direct Current

An electrical current that flows in one direction only.

• Direct Current Resistance

The resistance offered by a circuit to the flow of direct current.

• Direction of Lay

The direction, clockwise or counter-clockwise, of a conductor or group of conductors when looking axially down a cable length.

• Dissipation

The loss of energy, as the production of waste heat in a circuit.

• Distribution Cable

The transmission cable between the distribution amplifier and the drop cable in a CATV system.

• Drain Wire

An uninsulated wire usually place directly beneath an electrical contact with a grounded shield, which is used for making ground connections.

• Drop Cable

The transmission cable from the distribution cable to a dwelling in a CATV system.

• Duct

A tube or trough used for carrying electrical conductors and designed for mechanical protection.

• 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 primarily of ethylene propylene diene terpolymer.

• Ethylene Propylene Rubber (EPR)

An ozone resistant rubber consisting primarily of ethylene propylene copolymer.

• Extrusion

The process of applying an insulation or sheath compound over a conductor, or core by forcing material through a die.

• 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.

• Filler

The material used in multi-conductor cables to occupy large interstices formed by the assembled conductors, which imparts flexibility, strength and shape to the cable.

• Fire Integrity

This refers to 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 transmit a signal for a specific period of time while in the presence of a fire.

• Flame Retardance

The ability of a cable to restrict the propagation of flames in the event of a fire.

• Flexible Cable

A cable or cable component which is capable of repeated bending under the influence of an outside force.

• Foam Filled

The cellular structured insulation typically found in coaxial cable which acts as a dielectric.

• Foil

The film of metal or composite polymer which is used as a screen in the cable construction.

• Foiled Twisted Pairs Cable (FTP)

A cable containing multiple twisted pairs of wire enclosed 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 will transmit and one pair will receive simultaneously.

 

• Graded-Index Fibre

A multimode optical fibre in which the refractive index of the core is lower toward the outside of the fibre core and increases toward the centre.

• 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.

• Half Duplex

Allows data to travel in one direction at a time. Both Ethernet are capable of transmitting and receiving data but not simultaneously. They must use CSMA/CD to contend the right to send data.

• Halogen

A particular group of elements with similar bonding properties, consisting of flourine, chlorine, bromine and iodine. Halogen gases are poisonous when inhaled.

• Heat Endurance

The time of heat aging that a material can withstand before failing a specific physical test.

• Heat Resistance

The property of a material to resist the deteriorating effects of elevated temperatures.

• Helix

A spiral winding.

• Hertz

The term to denote cycles-per-second as an indication of frequency.

• HOFR

Heat and Oil Resistant, Flame Retardant (also Hypalon/CSP Chlorosulphated Polyethylene).

• Horizontal Cabling

The data cables connecting the wall outlets to the data cabinets in a data room. This includes Cat 5E and Cat 6.

• 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.

• Insertion Loss

The loss of power that results from inserting a component, such as a connector or splice, into a previously continuous path.

• 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

The undesired electrical or electromagnetic signal induced into a conductor.

• ISO

The International Organisation for Standardisation is a developer and publisher of standards and a network of the national standards institutes of 157 countries.

• ISP

Internet Service Provider. A company that provides a connection to the internet.

 

• Jabber

When a transceiver on an Ethernet network fails it may transmit continuously causing all other devices to think the network is busy. Its jabbering could stop all traffic on a network.

• 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.

• 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.

• LocalTalk

A slow form of LAN supported by the AppleTalk network protocol for MACs. A faster alternative would be Ethernet.

• Loss Factor

The dissipation multiplied by the dielectric constant of an insulation material.

• LSF

Low Smoke and Fume.

• LSZH

Low Smoke Zero Halogen.

• MAC

Media Access Control - a data communication protocol sub-layer, which is part of the Data Link layer (layer 2) of the OSI seven layer model.

• MAN

A Metropolitan Area Network is a data network designed for a town or city.

• Marker Tape

A tape, imprinted with the manufacturer's name, and various 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.

• Modem

A device that enables computers to transmit data over cables and telephone lines. It modulates and demodulates the signals between digital to analogue circuits.

• Moisture Absorption

The amount of moisture, in percentage, that an insulation or a jacket will absorb under specified conditions.

• MSAU

A Multistation Access Unit is a type of hub that connects network computers in a token ring network. It keeps the ring structure in tact at all times by bypassing single non-operating nodes.

• Multi mode

A type of Fibre Optic Cable used for signal tranmission over short distances. An MM Cable has a larger core than a Single Mode Cable and is therefore better at collecting light - it has higher numerical apertures. The information transmission capacity of a MM Cable is limited because it has higher pulse spreading rates.

• 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 Connector

An electrical connector designed to join Coaxial Cables.

• NBR

Nitrile Butadiene Rubber. 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.

• NIC

Network Interface Card - a piece of computer hardware to enable computers to communicate over a network.

• 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 propagate it down the core.

• NVP

NVP can refer to Nominal Velocity of Propagation or Network Voice Protocol. Nominal Velocity of Propagation is the speed an electrical signal will travel down a cable relative to the speed of light in space or vacuum. Network Voice Protocol predates Voice over Internet Protocol or VoIP. It was a computer networking protocol for transporting speech over packetised networks.

• 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 center 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.

• PABX

A Private Automatic Branch Exchange is a switchboard that serves a particular business or office.

• 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.

• Plug

A connector used for attachment on the free end of a cable.

• Polychloroprene (PCP)

A synthetic rubber with excellent flame retarding and abrasion resisting qualities used as a jacketing material. (Also see Neoprene).

• Polyethylene

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.

• POP

Point of Presence - an access point to the internet. POP can also stand for Post Office Protocol, a protocol used to retrieve email from the mail server.

• 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

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 - having taken into account the known attenuation of the cable.

• 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.

• Quad

A term used to describe a cable consisting of four separately insulated conductors twisted together.

• 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.

• RG 58

A specific type of coaxial cabled used for thin Ethernet networks.

• 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 especially for between floor applications.

• RJ11

Registered Jack number 11. RJ11 is a connector used for terminating telephone wires.

• RJ45

Registered Jack number 45. RJ45 is a standard connector for data communication systems - used for connecting computers to a Local Area Network.

• RL-DB

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.

• RS232

Recommended Standard 232 is a standard approved by the EIA for connecting serial devices. Updated versions of the standard have been introduced over the last two decades.

• RX

An abbreviation in the field of communications for the word ‘receive’.

• 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 in which each twisted pair is individually screened. It may also have an additional overall screen.

• Screening Effectiveness

The measure of the ratio of the power inside the cable to the total radiated power outside.

• SCSI

A Small Computer Systems Interface or SCSI (pronounced Skuzie) is a set of standards for connecting and transferring information between peripherals and computers.

• Secondary Coating

A coating applied directly to the primary coating of one or more 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.

• Segment

A segment is part of a computer network, separated from the rest of the network by a device such as a bridge, repeater or hub.

• 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 of the cable in service but bending or forming is permissible during installation.

• Sheath

The material, usually an extruded plastic or elastomer, applied outermost to 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 (such as foil) 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

Short for a 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 in which 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 (eg interference) in the first place are lost.

• Standards

An agreed set of guidelines used to maintain the level of quality in the production of cables and their component elements.

• Star network

A LAN where all devices (nodes) are attached to a central hub in a star configuration.

• Static Bending Radius

The smallest radius to which an installed cable can be bent once without impairing 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 composed of individual wires twisted together.

• Strength Member

An element which mechanically reinforces a cable, in particular against tension, compression or bending.

• Structured cabling

The fixed data and telecommunications cabling found in a building.

• SWA

Steel Wire Armour.

• Switch

A device in networks that reads MAC addresses and routes data to the individual node or network hub. Switches divide networks into smaller collision domains.

• Symmetrical Cable

Cables of which the transmission lines are symmetrical pairs. (See also Balanced Cable).

• Symmetrical Pair

The assembly of two insulated conductors twisted together. (See also Balanced Pair).

• 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.

• TDR

Time Domain Reflectometer. This electronic instrument is used to measure the length of cables and locate flaws and problems.

• Temperature Rating

The maximum temperature at which the insulating material may be used in continuous operation 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, eg. XLPE (cross-linked Polyethylene) and Neoprene.

• TIA

The Telecommunications Industry Association (TIA) is a trade association representing the global information and communications technology (ICT) industries.

• TIA 568A-4

Specifications for Category 5E from the TIA.

• Tinned Wire

Copper wire coated with tin to make soldering easier and to inhibit corrosion.

• Token Ring

Token Ring is a type of computer network where all the computers are arranged in a ring. A single token travels around the ring between computers. To send a message, a computer grabs the token and attaches a message to it. After transmission, it releases the token back onto the network.

• Topology

Topology can refer to both the physical and virtual design of a network.

• TPE

Thermoplastic Elastomer.

• Transceiver

A device designed to transmit and receive data over a network. Network Interface Cards (NICs), hubs and switches contain transceivers.

• Transfer Impedance

The ratio of the induced voltage inside the cable to the inductive current outside the cable.

• Transmission Line

A way of conveying electromagnetic energy between two points with a minimum of 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 in the field of communications for the word ‘transmit’.

• 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. An example would be coax.

• Underground Cable

A cable installed in an underground trough or duct system which separates the cable from direct contact with the soil.

• USB

Universal Serial Bus or USB is a series of connectivitiy specifications designed to allow the quick and easy connection of printers, scanners and other computer peripherals.

• 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.

• USOC

The USOC or Universal Service Ordering Codes Cabling system was introduced in the 70s as a means of identifying telecommunication services and equipment – originally in American telephone systems.

• UTP

Unshielded Twisted Pair. It is found in cables such as Cat 5e UTP PVC Cable and Cat 5e UTP PE External Cable. Twisting the pairs reduces the amount of electromagnetic interference (EMI) from external sources or cross talk between neighbouring pairs.

• Volt

The potential difference across a conductor when a current of one ampere dissipates one watt of power.

• Voltage Drop

The voltage developed between the terminals of a circuit component by the flow of current through the resistance or impedance of that part.

• Voltage Rating

The highest voltage that may be continuously applied to a wire or cord in conformance with standards or specifications.

• Voltage Withstand Test

A test used to stress the insulation of a product far beyond what it would it encounter during normal operation.

• 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.

• WAN

A WAN or Wide Area Network is a computer network that covers a large area and is used to connect LANs and other types of network together.

• Wave Length

The distance between positive peaks of a signal. As the frequency increases, and waves get closer together, the wavelength decreases.

• XLPE

Cross-linked Polyethylene

• 10Base-2

10Base-2 is also called Thin Ethernet (or Thinnet). Thin Ethernet uses RG-58 Coax Cable. The '10' refers to 10 Mbps, 'base' refers to baseband signalling (takes the whole bandwidth of the cable so only one device can transmit at one time) and '2' means that it is capable of data transmissions up to 200 metres (185 metres maximum length).

• 10Base-5

Thick Ethernet Cable - the '10' refers to 10 Mbps, 'base' refers to baseband signalling (takes the whole bandwidth of the cable so only one device can transmit at one time) and '5' means that it is capable of data transmissions up to 500 metres.

• 10BaseT

10 Mbps Ethernet running baseband signalling (takes the whole bandwidth of the cable so only one device can transmit at one time) over twisted pair copper cable.

• 50/125 micron

The standard European size for Fibre Optic Cables.

• 62.5/125 micron

The standard US size for Fibre Optic Cables.