Glossary Of Terms

About PCS Products Services Contacts What's New Information
Careers Price List Index Vendor Partners Training Promotions Clearance



5-Mil Copper

Solid Copper Shield. Provides added electrical protection.


IEEE's Cable TV MAC and PHY Protocol Working Group.




Available Bit Rate.

Abrasion Resistance

Ability of a wire, cable or material to resist surface wear.

Abrasion Stripper

More accurately described as "buffing stripper", which is a motorized device for removing flat cable insulation by means of one or two buffing wheels that melt the insulation and brush it away from the conductors.


Alternating current. Electric current that alternates or reverses polarity in a cyclical manner (e.g. 60 Hertz AC power)

Accelerated Aging

A test that simulates long time environmental conditions in a relatively short time.


Attenuation Crosstalk Ratio. The difference between attenuation and crosstalk, measured in dB, at a given frequency. Important characteristic in networking transmission to assure that signal sent down a twisted pair is stronger at the receiving end of the cable than are any interference signals imposed on that same pair by crosstalk from other pairs.


Asymmetric Digital Subscriber Line


Informal name of a digital audio standard established jointly by the AES (Audio Engineering Society) and EBU (European Broadcast Union) organizations.


Audio frequency.

Air Core

Cables that are not gel filled.

Air-Gap Dielectric

A coaxial design in which a monofilament of plastic holds the center conductor in place in a hollow plastic tube allowing the remainder of the dielectric to be air. Typical velocities of up to 84% can be achieved in this design.


A combination of two or more different polymers/metals. Usually combined to make use of different properties of each polymer/ metal.


Coated Aluminum Polyethylene.  Basic sheath.

Alternating Current (AC)

Electric current that alternates or reverses polarity in a cyclical manner (e.g. 60 Hertz AC power)


Amplitude modulation.


Conditions that exist in the environment of the cable. Conditions existing at a test or operating location prior to energizing equipment (e.g.: ambient temperature).

American Wire Gauge (AWG)

A standard for expressing wire diameter. As the AWG number gets smaller, the wire diameter gets larger.


Current handling capability expressed in amperes. The maximum current a conductor can carry without being heated beyond a safe limit.


A standard unit of current. Defined as the amount of current that flows when one volt of electromotive force (EMF) is applied across one ohm of resistance. One ampere of current is produced by one coulomb of charge passing a point in one second.


The magnitude of a current or voltage. It can be the maximum, minimum, average, or RMS value of an alternating current (AC) signal. These four magnitudes are the same for a direct current (DC) signal.


Representation of data by continuously variable quantities as opposed to a finite number of discrete quantities in digital.

Analog Signal

An electrical signal which varies continuously, not having discrete values. Analog signals are copies or representations of other waves in nature. An analog audio signal, for instance, is a representation of the pressure waves which make up audible sound.


To soften and relieve strains in any solid material, such as metal or glass, 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.


American National Standards Institute.


Aluminum Steel Polyethylene.  Provides mechanical and electrical protection.


The American Society for Testing and Materials, a standards organization which suggests test methods, definitions and practices.

Asynchronous Transfer Mode

The SONET standard for a packet switching technique which uses packets of a fixed length.


Asynchronous Transfer Mode.


The decrease in magnitude of a signal as it travels through any transmitting medium, such as a cable or circuitry. Attenuation is usually expressed logarithmically as the ratio of the original and decreased signal amplitudes. It is usually expressed in decibels (dB).


A term used to describe sounds within the range of human hearing (20 Hz to 20 kHz). Also used to describe devices which are designed to operate within this range.

Audio Frequency

Frequencies within the range of human hearing (approximately 20 Hz to 20 kHz).


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


Appliance Wiring Material. A UL designation for a type of wire.


The cable used to connect all systems of a multi-level distributed system to an intermediate system.


Housing on a connector that covers the area where the cable conductors connect to the connector contacts. It can be a metal housing providing continuity of the shield through IDC connectors.

Balanced Line

A cable having two identical conductors which carry voltages opposite in polarity, but equal in magnitude with respect to ground, suitable for differential signal transmission.


Balanced to unbalanced (Bal-un) transformer used to connect an unbalanced transmission line (i.e. coaxial cable) to a balanced system or cable, or vice versa. It can also provide impedance transformation, as 300 ohm balanced to 75 ohm unbalanced.


The difference between the upper and lower limits of a given band of frequencies. It is expressed in hertz.  The range of frequencies that a transmitted communications signal occupies or that a receiving system can accept.  For example, it takes more bandwidth to download a photograph in a second than to download a page of text.  Virtual reality and three-dimensional audio/visual presentations require even more.


Rate of digital transmission equal to the reciprocal of the time of one output signaling element.


A unit that represents the logarithm of the ratio of two levels. One bel equals the base 10 logarithm of the ratio of two power levels. It is also equal to the base 10 logarithm of square of the ratio of two voltage or current levels, provided the impedances are the same at the two levels. See dB.


A leading manufacturer of the specialty wire, cable and fiber products needed for new applications in data, audio, video and voice signal transmission, among other things.


Belden trademark for highly effective electrostatic shield of reinforced metallic foil.


Solderable Belden magnet wire combining insulating films of polyurethane for excellent dielectric characteristics and nylon for mechanical protection.

Belflex® A premium hybrid matte-finish jacket material that exhibits superior flexibility at low temperatures along with excellent abrasion resistance compared to standard PVC jacketing materials.

Bend Loss

A form of increased attenuation caused by (a) having an optical fiber curved around a restrictive radius of curvature or (b) microbends caused by minute distortions in the fiber imposed by externally induced perturbations.

Bend Radius

Radius of curvature that a flat, round, fiber optic or metallic cable can bend without any adverse effects.


A tape or thread used for holding assembled cable components in place.


One binary digit.

Bit Error Rate

The number of errors occurring in a system per unit of time (e.g. bits per second)

Bits Per Second

The number of binary bits that can be transmitted per second (bps) - i.e. Mbps (Mega = million), Gbps (Giga = billion).


Abbreviation for "Bayonet Neil Concelman". A coaxial cable connector used extensively in video and R. F. applications and named for its inventors.


1. Adhesive application of a metallic shielding tape to the dielectric of a coaxial cable to improved electrical performance and ease of connector installation. Also refers to adhesive application of a metallic shielding taper to the jacket of a cable. 2. Steel is bonded to polyethylene with a copolymer adhesive All STALPETH and some ASP cables are bonded.  Provides extra strength to jacket, primarily used in underground applications.

Bonded ASP

Aluminum Steel Polyethylene where the steel is bonded to polyethylene for strength.  Filled cables for use in ducts.


The method used to produce good electrical contact between metallic parts of any device. Used extensively in automobiles and aircraft to prevent static buildup. Also refers to the connectors and straps used to bond equipment.


An amplifier inserted into a cable to increase the signal amplitude in order to compensate for signal loss due to attenuation. This extends the transmission range of the cable. Transformers may be employed to boost ac voltages. The term booster is also applied to amplifiers used in television receiving antenna systems.


Bits per second (see).


Binary Phase Sift Keying. A type of digital transmission where two phases of the signal are possible to represent binary one and zero.


A group of textile or metallic filaments interwoven to form a tubular flexible structure which may be applied over one or more wires, or flattened to form a strap.

Braid Angle

The angle between a strand of wire in a braid shield and the longitudinal axis (i.e.axis along the length of the center) of the cable it is wound around.

Breakdown Voltage

The voltage at which the insulation between two conductors will fail and allow electricity to conduct or 'arc'.


The point at which a conductor or conductors are separated from a multi-conductor cable to complete circuits at various points along the main cable.


Basic Rate Interface ISDN.


The technique used to multiplex multiple networks on a single cable without interfering with each other.  Technologies that allow you to transmit or receive higher volumes of data at higher speeds.


A protective coating over an optical fiber.

Buffing Stripper

A motorized device for removing flat cable insulation by means of one or two buffing wheels that melt the insulation and brush it away from the conductors. Also called Abrasion Stripper.

Bunch Strand

Conductors twisted together with the same lay and direction without regard to geometric pattern.


Cables that are required to go underground.

Bus-bar Wire

Uninsulated tinned copper wire used as a common lead.

Butyl Rubber

A synthetic rubber with good electrical insulating properties.


A group of eight adjacent binary digits (8 bits).


Capacitance (electrical). Celsius (temperature).


A group of individually insulated conductors or subcomponents twisted helically.

Cable Modem

A device that enables you to hook up your PC to a local cable TV line and receive data at much faster rates than telephone modems and ISDN lines.  A strong competitor to DSL telephone service.


The grouping or twisting together of two or more insulated conductors or subcomponents to form a cable.


Coated Aluminum, Coated Steel, Polyethylene.  Provides additional strength and protection.

Canadian Electrical Code (CEC)

Canadian version of the US National Electrical Code (NEC).


Carrierless Amplitude Phase Modulation.


The ability of a dielectric material between conductors to store energy when a difference of potential exists between the conductors. The unit of measurement is the farad. Cable capacitance is usually measured in picofarads (pF).

Capacitive Crosstalk

Cable crosstalk or interference resulting from the coupling of the electrostatic field of one conductor upon one or more others.

Capacitive Reactance

The opposition to alternating current due to the capacitance of a capacitor, cable, or circuit. It is measured in ohms and is equal to 1/(2*pi*f*C) where pi is approximately 3.1416, f is the frequency in Hz, and C is the capacitance in farads.


Two conducting surfaces separated by a dielectric material. The capacitance is determined by the area of the surfaces, type of dielectric, and spacing between the conducting surfaces.

Carrier Strip

Also referred to as substrate. A film that is on one side of a laminated flat cable.


Coated Aluminum, Coated Steel.


Rating of a local area network (LAN) cable established by TIA/EIA to indicate the level of electrical performance.

Category Cables

Belden manufactures Category 3 to 7 cables, all high performance twisted pair data cables.  The higher the category number, the greater the bandwidth.  Category 7 is currently the highest performance telecommunication wire available.  Ours is certified to applicable UL standards.


Abbreviation for Community Antenna Television.  Cable TV.


Citizens band.


Constant Bit Rate.


Closed-circuit television.

Cellular Polyethylene

Expanded or "foam" polyethylene, consists of individual closed cells of inert gas suspended in a polyethylene medium. The result is a desirable reduction of the dielectric constant compared to solid polyethylene, which decreases attenuation and increases the velocity of propagation.

Center-to-Center Distance

Pitch. Nominal distance from center-to-center of adjacent conductors within a cable. When conductors are flat, pitch is usually measured from the reference edge of a conductor to the reference edge of the adjacent conductor.


The horizontal cable including the workstation outlet and patch panel in the telecommunications closet plus a maximum combined length of up to ten meters of patch cable at each end (maximum length of 100 meters).

Characteristic Impedance

In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. Or the impedance which makes a transmission cable seem infinitely long, when connected across the cable's output terminals.

Chrominance Signal

The portion of a video signal that contains the color information.


A system of conducting media designed to pass an electric current.

Circular Mil

Area of a wire that is one-thousandth of an inch (.001 inch, one mil) in diameter. This area is pi/4 of a square mil. The circular mil area (CMA, cmil) equals the diameter in mils squared. By knowing the CMA of various conductors, they can be used to determine what conductivity and gage size various combinations will produce.


A low refractive index material that surrounds the core of an optical fiber causing the transmitted light to travel down the core and protects against surface contaminant scattering or a layer of metal applied over another. Cladding is often chosen to improve conductivity or to resist corrosion.


Central Office.

Coaxial Cable

A cylindrical transmission line comprised of a conductor centered inside a metallic tube or shield, separated by a dielectric material, and usually covered by an insulating jacket. Used by cable TV companies to distribute signals to homes and businesses. Also used by telephone companies in some applications and by cellular telephone, radio, and television installations.

Coil Effect

The inductive effect exhibited by a spiral-wrapped shield, especially above audio frequencies.

Color Code

A system of different colors or stripes used to identify components of cables such as individual conductors or groups of conductors.


Commercial Online Service.

Component Video

The unencoded output of a camera, video tape recorder, etc., whereby each red, green, and blue video signal is transmitted down a separate cable (usually coax) to improve picture quality. Can also refer to a video system where the luminance and chrominance video components are kept separate.

Composite Cable

Cable having conductors with two or more AWG sizes or more than one cable type.

Composite Video

The encoded output of a camera, video tape recorder, etc., whereby the red, green, and blue video signals are combined with the synchronizing, blanking, and color burst signals and are transmitted simultaneously down one cable.

Concentric Stranding

A group of uninsulated wires twisted together and containing a center core with subsequent layers spirally wrapped around the core with alternating lay directions to form a single conductor.


The ability of a material to allow electrons to flow, measured by the current per unit of voltage applied. It is the reciprocal of resistivity and is measured in siemens (S) or mhos.


A substance, usually metal, used to transfer electrical energy from point to point.


A tube of metal or plastic through which wire or cable can be run. Used to protect the wire or cable and, in the case of metal conduit, to contain the fire of a burning wire or cable.


A device designed to allow electrical flow from one wire or cable to a device on another cable. A connector will allow interruption of the circuit or the transfer to another circuit without any cutting of wire or cable or other preparation.


Trademark of Copperweld Steel Co. for copper-clad steel conductor.


A very flexible insulated cable.


The light conducting central portion of an optical fiber with a refractive index higher than that of the cladding. The center of a cable construction. Most often applies to a coaxial cable, where the core is the center conductor and the dielectric material applied to it.


The ionization of gasses about a conductor that results when the potential gradient reaches a certain value.


The transfer of energy (without direct electrical contact) between two or more cables or components of a circuit.


How well a metal shield covers the underlying surface. Measured in percent.


Chlorinated polyethylene can be used as either a thermoplastic or thermoset. It is a tough chemical and oil-resistant material and makes an excellent jacket for industrial control cable. As a thermoset, it can be used as an oil resistant cord jacket. Other outstanding properties include low water absorption and superior crush resistance, which are important attributes in industrial control applications.


Abbreviation for cycles per second. This term has been replace by hertz is common usage.


Central Processing Unit.


A type of interference caused by signals from one pair or cable being coupled into adjacent pairs or cables. Can occur with audio, data, or RF signals.


Cathode Ray Tube.


Abbreviation for Canadian Standards Association, the Canadian version of the Underwriters Laboratories.


Carrier Sense Multiple Access/Collision Detection.


Customer Service Representative.



Current Carrying Capacity

The maximum current a conductor can carry without being heated beyond a safe limit. Ampacity.

Current Loop

A two wire transmit/receive interface.

Current, Alternating (ac)

Electric current that alternates or reverses polarity in a cyclical manner (e.g. 60 Hertz AC power).

Current, Direct (dc)

Electrical current whose electrons flow in one direction only and is generally constant.

Cut-through Resistance

A test to determine the ability of a material to withstand the application of blades or sharp edges without being cut.


A component digital video recording format that conforms to the CCIR-601 standard. Records on 19 mm magnetic tape. (Often used incorrectly to indicate component digital video).


A composite digital video recording format. Records on 19 mm magnetic tape.


A composite digital video recording format. Records on 1/2 inch (12.7 mm) magnetic tape.

Daisy Chain

A cable assembly with three or more termination areas.


Belden trademark for foam polyolefin.


Digital Audio Video Council.




Direct Broadcast Satellite.


Direct current.

DC Resistance

See resistance.

Decibel (dB)

A decibel is one-tenth of a bel and is equal to 10 times the logarithm of the power ratio, 20 times the log of the voltage ratio, or 20 times the log of the current ratio. Decibels are also used to express acoustic power, such as the apparent level of a sound. The decibel can express an actual level only when comparing with some definite reference level that is assumed to be zero dB.

Delay Line

A transmission line or equivalent device designed to delay a wave or signal for a specific length of time.


Dual Expanded Plastic Insulated Conductor (Foam Skin).  Decreases outside diameter of cable.

Derating Factor

A multiplier used to reduce the current carrying capacity of conductors in more adverse environments, such as higher temperature, or where multiple conductors are together in one conduit.


Data Encryption Standard.


Dynamic Host Configuration Protocol.


An insulating (non-conducting) medium. It is the insulating material between conductors carrying a signal in a cable. In coaxial cables it is between the center conductor and the outer conductor. In twisted pair cables it is the insulation between conductors plus any surrounding air or other material.

Dielectric Breakdown

Any change in the properties of a dielectric that causes it to become conductive. Normally a catastrophic failure of an insulation because of excessive voltage.

Dielectric Constant

Also called relative permittivity. That 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. Actually, the ratio of the capacitance of a capacitor using the dielectric to the capacitance of an identical capacitor using a vacuum (which has a dielectric constant of 1) as a dielectric. A number which indicates the quality of a material to resist holding an electrical charge when placed between two conductors.

Dielectric Heating

The heating of an insulating material when placed in a radio-frequency field, caused by internal losses during the rapid polarization reversal of molecules in the material.

Dielectric Loss

The power dissipated in a dielectric as the result of the friction produced by molecular motion when an alternating electric field is applied.

Dielectric Strength

The voltage an insulation can withstand before it breaks down. Usually expressed as "volts per mil".

Dielectric Withstand Voltage

The voltage an insulation can withstand before it breaks down. Usually expressed as "volts per mil".

Digital Signal

An electrical signal which possesses two distinct states (on/off, positive/negative).


The cause of bandwidth limitations in an optical fiber. Dispersion causes a broadening of input pulses along the length of the fiber. Two major types are (a) mode dispersion caused by differential optical path lengths in a multimode fiber, and (b) material dispersion caused by a differential delay of various wavelengths of light in a wave guide material.


Any undesired change in a wave form or signal.

Distribution Cables

In a CATV system, the transmission cable between the distribution amplifier and the drop cable.

Disturbed Conductor

A conductor that receives energy generated by the field of another conductor or an external source. e.g. the quiet line.


Discrete Multitone.


Data Over Cable Service Interface Specification (trade mark). Defines interface requirements for cable modems involved in high-speed data distribution over cable television system networks.

Drain Wire

A non-insulated wire in contact with parts of a cable, usually the shield, and used in the termination to that shield and as a ground connection.

Drop Cable

In a CATV system, the transmission cable from the distribution cable to a dwelling.


Digital Subscriber Line.  A technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines.  A DSL line can carry both data and voice signals, with the data part of the line remaining continuously connected.  Currently competes with the cable modem in bringing broadband services to homes and small businesses.

Duobond II

Belden trademark for a laminated shielding tape consisting of heat sensitive adhesive, aluminum foil, polyester or polypropylene, and aluminum foil.


Belden trademark for a shield in which metallic foil is applied to both sides of a supporting plastic film.


Digital Video Broadcasting.


Voltage (electromotive force).


British terminology for zero-reference ground.

Edge Margin



Electronic Field Production. Video production for commercials, television shows and other non-news purposes done outside the studio.


Electronic Industries Association (formerly RMA or RETMA).


Any material that will return to its original dimensions after being stretched or distorted.


Referring to the combined electric and magnetic fields caused by electron motion through conductors.

Electromagnetic Coupling

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

Electron Volt

A measure of the energy gained by an electron passing through an electric field produced by one volt.


Pertaining to static electricity, or electricity at rest. An electric charge, for example.

Electrostatic Coupling

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


Equal Level Far End Crosstalk (dB). A subtraction of attenuation from FEXT. By subtracting the attenuation, ELFEXT negates the effects of attenuation on the interference as it propagates down the cable, thus bringing it to an "equal level".


The increase in length of a wire or cable cause by longitudinal tension.


Electromotive force (voltage).


Electromagnetic Interference.


The capability of doing work.

Energy Dissipation

Loss of energy from a system due to the conversion of work energy into an undesirable form usually heat. Dissipation of electrical energy occurs when current flows through a resistance.


Electronic News Gathering.


Ethylene-propylene-diene monomer rubber. A chemically cross-linked elastomer with good electrical insulating properties and excellent flexibility at high and low temperatures. It has good insulation resistance and dielectric strength, as well as excellent abrasion resistance and mechanical properties. EPDM has better cut-through resistance than Silicone rubber, which it replaces in some applications.


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


More than one layer of helically laid wires with the length of the lay the same for each layer.


Abbreviation for a copper refining process called Electrolytic Tough Pitch. This process produces a conductor that is 99.95% pure copper (per ASTM B115) resulting in high conductivity.


Electron volt.

Expanded Polyethylene

Expanded or "foam" polyethylene, consists of individual closed cells of inert gas suspended in a polyethylene medium, resulting in a desirable reduction of the dielectric constant.

Extruded Cable

Conductors are simultaneously insulated and the cable is formed by a continuous extrusion process.




A unit of capacity that will store one coulomb of electrical charge when one volt of electrical pressure is applied.


Fire Alarm and Signal Cable, CSA (Canadian Standards Association) Cable Designation.


Frequently Asked Question.


Abbreviation for flat conductor flat cable.


Fiber Distributed Data Interface.


Forward Error Correction.


Energy that is extracted from a high-level point in a circuit and applied to a lower level. Positive feedback reduces the stability of a device and is used to increase the sensitivity or produce oscillation in a system. Negative feedback, also called inverse feedback, increases the stability of a system as the feedback improves stability and fidelity.

Feeder Cable

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


Fluorinated ethylene-propylene. A thermo-plastic material with good electrical insulating properties and chemical and heat resistance.


Composed of and/or containing iron. A ferrous metal exhibits magnetic characteristics.


Far End Crosstalk. Crosstalk induced on the pairs, measured at the "far" end of the cable, referenced to the near end input signal. Usually expressed in decibels.


A single, separate optical transmission element characterized by core and cladding.

Fiber Optics

Light transmission through optical fibers for communication and signaling.  A technology that transmits information as light pulses along a glass or plastic fiber.  Optical fiber carries much more information than conventional copper wire and is generally not subject to interference.  Most telephone company long-distance lines are optical fiber.  See RUS 1755.900.

Fiber to the home (FTTH)

A technology that provides voice, data and video services from the phone company's branch office to local customers over an all-fiber optic link.  Still in its infancy, FTTH technology is substantially more expensive and labor-intensive to install and maintain than competing technologies.


An area through which electric and/or magnetic lines of force pass.


Cables that are gel filled.


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


Belden trademark for a plenum grade chloride-based thermoplastic jacketing material with low smoke and low flame spread properties; more flexible than traditional fluorocopolymer jacket materials. Cables jacketed with Flamarrest meet the UL Standard 910, Plenum Cable Flame Test.

Flame Resistance

The ability of a material not to fuel a flame once the source of heat is removed.

Flat Cable

Also referred to as planar and/or ribbon cable. Any cable with two or more parallel conductors in the same plane encapsulated by insulating material.

Flat Conductor

A conductor with a width-to-thickness ratio of arbitrarily 5 to 1 or greater.

Flat Conductor Cable

A flat cable with a plurality of flat conductors.

Flex Life

The qualification of the number of times a cable may bend before breaking.


The ability of a cable to bend in a short radius. The ability of a cable to lay flat or conform to a surface as with microphone cables.


Referring to a circuit which has no connection to ground.


Generic term for PVDF.


Frequency modulation.

Foam Polyethylene

Expanded or "foam" polyethylene, consists of individual closed cells of inert gas suspended in a polyethylene medium, resulting in a desirable reduction of the dielectric constant.


FR-TPE, flame retarded thermoplastic elastomer, is a rubber-like plastic that has properties similar to rubber yet is processed as a thermoplastic. It is used as the insulation and jacket in an all TPE construction which meets UL 13 and 1277 industrial cable requirements. It has good electrical properties, abrasion resistance, colorability and flame retardancy. This compound is ideal for cold weather applications.


Flame retardant ethylene propylene is a special flame retardant version of EPDM rubber. It is designed for use as an industrial control insulation and has excellent electrical characteristics, deformation resistance, and also meets the flame retardant needs of industrial control cables.


The number of times a periodic action occurs in one second. Measured in Hertz.

Frequency Response

The amplitude versus frequency characteristics of a device. Also may refer to the range of frequencies over which the device operates within prescribed performance

Frequency, Power

Normally, the 50 or 60 hertz power used to operate most AC powered equipment. The frequency of AC power supplied by electric utilities companies.


Frequency Shift Keying.




The physical diameter of a wire. A standard for expressing wire diameter. As the AWG number gets smaller, the wire diameter gets larger.


The increase of voltage, current, or power over a standard or previous reading. Usually expressed in decibels.


A solderable, extra tough film insulation developed b Belden for use in geophysical cables and miniature cables.


One billion.

Gigahertz (GHz)

A unit of frequency equal to one billion hertz.




Gopher Resistant Copper Alloy.  Provides shield and added protection in a single layer.




A type of optical fiber in which the refractive index of the core is in the form of a parabolic curve, decreasing toward the cladding. This type of fiber provides high bandwidth capabilities.


An electrical connection between a circuit and the earth. Also refers to a conductor connected to earth. In some instances, can refer to a central metallic point designated as having "zero" potential.

Ground Conductor

A conductor in a transmission cable or line that is grounded.

Ground Loop

A completed circuit between shielded pairs of a multiple pair created by random contact between shields. An undesirable circuit condition in which interference is created by ground currents when grounds are connected at more than one point.

Ground Potential

The potential of the earth. A circuit, terminal, or chassis is said to be at ground potential when it is used as a reference point for other potentials in the system.


Symbolic designation for magnetic field intensity. Abbreviation for henrys (unit of inductance).


Thermoplastic fluoropolymer material with excellent chemical resistance, electrical properties, thermal characteristics, and impact resistance.

Haloarrest I

Haloarrest I is a non-halogenated flame retarded thermoplastic polyolefin with excellent low smoke and flame properties. It is used as a jacket over the XLPE insulated singles (non-XHHW), and the entire construction meets the UL 13 and 1277 specifications as a non-halogenated PLTC/TC cable. Haloarrest I meets the European Specifications on acid gas evolution and % Halogen content. This jacket can also be used with XHHW conductors for wet ratings.


A flat cable or group of cables, usually with many breakouts with the wire ends prepared for termination or terminated to connectors and ready to install.


High bit-rate Digital Subscriber Line.


The amount by which a cable ACR exceeds the specified requirements. The TIA/EIA 568B standard specifies a minimum of 10 dB of ACR for Category 5e certification at 100 MHz.


Unit of inductance (H) that will produce a voltage drop of one volt when the current changes at the rate of one ampere per second.

Hertz (Hz)

Unit of frequency equal to one cycle per second.

Heterogeneous Insulation

A cable insulating system composed of two or more layers of different insulating materials.


High Frequency. International Telecommunication Union designation for the 3-30 MHz band of frequencies.


Hybrid Fiber/Coaxial.

High Frequency

International Telecommunication Union designation for the 3-30 MHz band of frequencies.

Homogeneous Insulation

A complete cable insulation structure whose components cannot be identified as layers of different materials.

Hook-Up Wire

Single conductor wire with various types of insulation.

Horizontal Cable

Cable used between the workstation outlet and the telecommunications closet. Limited to 90 meters maximum per TIA/EIA 568B.1.


High-Speed Cable Data Service.


Hypertext Markup Language.


Hypertext Transfer Protocol.


Term used to describe noise in a audio, video, or other system that comes from 60 Hz power or its harmonic(s). So named for the low-frequency humming sound produced in audio systems. Usually hum is the result of undesired coupling from a 60 Hz source or of inadequate filtering of the DC output of an AC input power supply.


A DuPont trade name for a synthetic rubber (chlorosulfonated polyethylene) used as insulating and jacketing material for wire and cable.


Symbol used to designate current.

I/O Interconnection

Input/Output interface to the "outside world."


Formula for power in watts, where I=current in amperes, R=resistance in ohms.


Insulated Cable Engineers Association.


Insulation Displacement Connector. Type of connector where contact is made to the cable conductor(s) by cutting through the individual conductor's insulation. The conductor does not need to have its insulation removed prior to connection. Flat cable often uses IDCs to simultaneous connect all conductors.


ISDN Digital Subscriber Line.


Institute of Electrical and Electronic Engineers.


Internet Engineering Task Force.


Intermediate Frequency.


Interrupted Feedback (Foldback). Interruptible Feedback (Foldback). A monitoring scheme often used in television where the feed of program audio to an on-air person can be interrupted with directions, cues, or other information. Usually integrated into the intercom system.


Internet Group Management Protocol.


The total opposition that a circuit offers to the flow of alternating current or any other varying current at a particular frequency.

Impedance Match

A condition whereby 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 Sub

A section of transmission line or pair of conductors cut to match the impedance of a load. Also called matching sub.

Impedance Matching Transformer

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

Impedance, Characteristic

In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. Or the impedance which makes a transmission cable seem infinitely long, when connected across the cable's output terminals.

Impedance, High

Generally, the area of 25,000 ohms or higher.

Impedance, Low

Generally, the area of 1 through 600 ohms.

Index Edge

Reference Edge.


The property of wire which stores electrical current in a magnetic field around the wire. By coiling wire, the effect can be intensified. It is measured in Henrys.


The phenomenon of a voltage, magnetic field, or electrostatic charge being produced in an object from the source of such fields.

Induction Heating

Heating a conducting material by placing it in a rapidly changing magnetic field. The changing field induces electric currents in the material and losses account for the resultant heat.

Inductive Crosstalk

Crosstalk resulting from the coupling of the electromagnetic field of one conductor upon another.

Injection Laser Diode

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


Integrated Network Management System.


A signal (or power) which is applied to a piece of electric apparatus or the terminals on the apparatus to which a signal or power is applied.

Insertion Loss

A measure of the attenuation of a cable and/or component(s) by determining the output of a system before and after the device is inserted into the system.


A material having good dielectric properties which is used to separate close electrical components, such as cable conductors and circuit components.

Insulation Displacement Connector (IDC)

A mass termination connector for flat cable with contacts that displace the conductor insulation to complete termination.

Insulation Stress

The molecule separation pressure caused by a potential difference across an insulator. The practical stress on insulation is expressed in volts per mil.


The region where two systems or a major and a minor system meet and interact with each other.


Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into other electronic equipment.

Intermediate Frequency

A frequency to which a signal is converted for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages.


The formation of ions. Ions are produced when polar compounds are dissolved in a solvent and when a liquid, gas, or solid is caused to lose or gain electrons due to the passage of an electric current.

Ionization Voltage

The potential at which a material ionizes. The potential at which an atom gives up an electron.


Internet Protocol.


IP Over Cable Data Network working group of the IETF.


Insulation Resistance.

IR Drop

The designation of a voltage drop in terms of current and resistance. See also Voltage Drop.


Inter Relay Chat.


Ignition radiation suppression.


Integrated Services Digital Network.  An alternative to telephone modems that allows digital transmission over ordinary telephone copper wire and other media.  Home and business users can get highly graphic Web pages more quickly through ISDN adapters than through dial-up connections.


International Standards Organization.


The ability of a circuit or component to reject interference, usually expressed in dB.


Internet Service Provider.


Instructional Television Fixed Service.


International Telecommunications Union.


Pertaining to wire and cable, the outer protective covering that may also provide additional insulation.


A short length of conductor or flat cable used to make a connection between terminals or around a break in a circuit, or between circuit boards.




1000 electron volts.


One thousand.


Tensile strength in thousands of pounds per square inch.


Kilovolt (1000 volts).


Kilo Volt-ampere. One thousand volt-amperes (VA). See also VA.




Symbol for inductance.

Laminated Cable

Insulated or uninsulated wires which are encapsulated by two sheets of laminate material to maintain a predetermined pitch.


Local Area Network. A data network connecting any number of users, intended to serve a small area. A group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area.


A coherent source of light with a narrow beam and a narrow spectral bandwidth (about 2nm).


The length measured along the axis of a wire or cable required for a single strand (in stranded wire) or conductor (in cable) to make one complete turn about the axis of the conductor or cable. In a twisted pair cable, the lay length is the distance it takes for the two wires to completely twist around each other.

Lay Direction

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

Lead Dress

The placement or routing of wiring and component leads in an electrical circuit.


The cable that provides the path for r-f energy between the antenna and the receiver or transmitter.


The undesirable passage of current over the surface of or through an insulator.


Local Exchange Carrier.


A measure of the difference between a quantity or value and an established reference.


Low frequency.  International Telecommunication Union designation for the 30-300 kHz band of frequencies.

Light Emitting Diode (LED Source)

A semiconductor device that emits incoherent light formed by the P-N junction. Light intensity is roughly proportional to electrical current flow.


The ability of a cable to lay flat or conform to a surface as with microphone cables. The ability of a cable to bend in a short radius.

Line Drop

A voltage loss occurring between any two points in a power or transmission line. Such loss, or drop, is due to the resistance, reactance, or leakage of the line. See also Voltage Drop and IR Drop.

Line Equalizer

A reactance (inductance and/or capacitance) connected in series with a transmission line to alter the frequency-response characteristics of the line.

Line Level

Refers to the output voltage level of a piece of electronic equipment. Usually expressed in decibels (e.g.. 0 dBV).

Line Voltage

The value of the potential existing on a supply or power line.


Local Multipoint Distribution Service


A device that consumes power from a source and uses that power to perform a function.

Loaded Line

A transmission line that has lumped elements (inductance or capacitance) added at uniformly spaced intervals. Loading is used to provide a given set of characteristics to a transmission line.


A transmission line that has lumped elements (inductance or capacitance) added at uniformly spaced intervals. Loading is used to provide a given set of characteristics to a transmission line.

Local Area Network

A data network connecting any number of users, intended to serve a small area. See also LAN.

Long-wire Antenna

An antenna conductor length in excess of one-half of a wavelength.


Energy or signal lost without accomplishing useful work.


Having high losses resulting in efficiency.

Low Frequency

International Telecommunication Union designation for the 30-300 kHz band of frequencies.

Luminance Signal

The portion of the composite video signal that represents the brightness or the black and white information.


Prefix for milli or one-thousandth.


Mutual inductance. The abbreviation for mega or 1 million. And also indicates 1000 (one thousand) feet in the wire industry. Lower case m is for milli or one-thousandth. See also m.


Notation representing 1000 feet.


milliampere (one-thousandth of an ampere).


Media Access Control (layer of OSI Reference Model).


Metropolitan Area Network. A data network intended to serve the area of a city or an area of similar size.

Manufacturing Automation Protocol

A manufacturing automation protocol based on IEEE 802.4 standards.


Manufacturing Automation Protocol. A manufacturing automation protocol based on IEEE 802.4 standards.


Distance between reference edge of cable and nearest edge of first conductor or center of first conductor.


The process of simultaneously terminating all conductors in a single operation.

Matte Finish PVC

A special formulation of PVC which very closely looks and feels like rubber.


Abbreviation for Master Antenna Television.




Mega bits per second - the number of bits, in millions, transmitted per second.


Multimedia Cable Network System Partners Ltd.


Multipoint Distribution System.


Prefix meaning million.

Megahertz (MHz)

Unit of frequency equal to one million hertz.

Metropolitan Area Network

A data network intended to serve the area of a city or an area of similar size. See also MAN.


Microfarad (one-millionth of a farad). Modern abbreviation is uF (lower case Green mu followed by F).


The unit of conductance equal to the reciprocal of the unit of resistance (ohm).


Megahertz (see also).


Prefix meaning one-millionth.


One-millionth of a farad (uf, ufd, mf, and mfd are common abbreviations).


One-millionth of a microfarad (uuf, uufd, mmf, mmfd are common abbreviations). Modern usage is picofarad (pF).


Millionth of a meter.


Noise caused by mechanical excitation of a system component. In a single-conductor microphone cable, for example, microphonics can be caused by the shield rubbing against the dielectric as the cable is flexed.


A unit of length equal to one thousandth of an inch (.001").


Prefix meaning one-thousandth.


Multichannel Multipoint Distribution System.


A single electromagnetic wave traveling in an optical fiber.


Modulator-Demodulator. Device that converts signals in one form to another form compatible with another kind of equipment.


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

Molded Cable

Cable assemblies with molded connectors on one or both ends.

Mono Filament

A single strand filament as opposed to a braided or twisted filament.


Multiple System Operator. Cable TV term referring to companies that operator multiple cable TV systems in numerous cities.


Simple Mail Transfer Protocol.

Multi-Conductor Cable

Cable with more than one conductor.


A technique for putting two or more signals into a single channel.

Mutual Capacitance

Effective capacitance between two conductors when the effects of the other conductors and shield, if present, are removed.


Millivolt (one-thousandth of a volt).


Milliwatt (one-thousandth of a watt).


DuPont trademark for polyethylene terephtalate (polyester) film.


Type of coaxial connector named after its inventor, Paul Neil of Bell Labs.



Nanometer (nm)

One billionth of a meter.


One billionth of a second.


Network Access Point.

National Electrical Code (NEC)

A publication of the National Fire Protection Association (NFPA) which outlines requirements for electrical wiring and building construction.


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


National Electrical Code. A publication of the National Fire Protection Association (NFPA) which outlines requirements for electrical wiring and building construction.


National Electrical Manufacturers Association.


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


A network is a method of data communications between computers.


Near-end Crosstalk. Crosstalk induced on the pairs, measured at the end "near" the transmitter. Usually expressed in decibels.


National Fire Protection Association.


One half byte (4 bits).


Network Operations Center.


In a cable or circuit, any extraneous signal which tends to interfere with the signal normally present in or passing through the system.


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

Non-Paired Cable

Cable with two or more cabled conductors that are not in a paired configuration.


A description for a cable that does not meet the requirements of UL 910 CMP flame test. Such a cable cannot be installed in an area that is used for air return (plenum).


The removal of the web section between conductors of a flat cable to aid in stripping, slitting, and termination.


National Television System Committee.  Organization that formulated standards for the current U.S. color television system. This system is used in most countries of the Americas and in other parts of the world. It was designed to be compatible with the existing monochrome TV sets, so that they would not become obsolete. Color televisions would also be able to receive monochrome transmissions. NTSC uses a 3.579545 MHz subcarrier whose phase varies with the instantaneous hue of the televised color and whose amplitude varies with the instantaneous saturation of the color. NTSC employs 525 lines per frame, 29.97 frames per second and 59.94 fields per second.

Numerical Aperture (NA)

A measure of the angular acceptance for a fiber. It is approximately the sine of the half-angle of the acceptance cone.


An abrasion-resistant thermoplastic with good chemical resistance.


Orthogonal Frequency Division Multiplexing.


Abbreviation for oxygen-free, high conductivity copper. It has 99.95% minimum copper content and an average annealed conductivity of 101% compared to standard copper.


The unit of electrical resistance. The value of resistance through which a potential difference 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 Waveguide Fiber

A transparent filament of high refractive index core and low refractive index cladding that transmits light.


Open System Interconnect (Model for networking protocols).


Operations Support Systems.


The useful power or signal delivered by a circuit or device.


Extremely reactive form of oxygen, normally occurring around electrical discharges and present in the atmosphere in small but active quantities. In sufficient concentrations is can break down certain rubber insulations under tension (such as a bent cable).

Paired Cable

Cable with conductors cabled in groups of two.


Phase Alternation Line. PAL is a European color TV system featuring 625 lines per frame, 25 frames and 50 fields per second. Used mainly in Europe, China, Malaysia, Australia, New Zealand, the Middle East, and parts of Africa. PAL-M is a Brazilian color TV system with 525 lines per frame, 30 frames and 60 fields per second.

Parallel Circuit

A circuit in which the identical voltage is presented to all components, with current dividing among the components according to the resistances or the impedances of the components.

Parallel Digital

Digital information that is transmitted in parallel form. The digits are sent on separate conductors rather than sequentially on one transmission line (serial). Often used informally to refer to parallel digital television signals.


Polyethylene Aluminum Steel Polyethylene.  provides additional lightning and gopher protection.


A flexible piece of cable terminated at both ends with plugs. Used for interconnecting circuits on a patchboard, in a wiring closet, or at the work area.


Personal Computer.




The maximum instantaneous value of a varying current or voltage.

Peel Strength

The force necessary to separate two adjacent conductors of a bonded or laminated flat cable.


The uniformly spaced cable impedance variations that result in addition of the reflections of a signal. The distance between them is the half wavelength most affected. Multiples of that frequency are also affected. Even very slight variations, which appear over and over in a construction or installation, can have major effects on signal integrity because of periodicity.

Permanent Link

The horizontal cable including the workstation outlet and patch panel in the telecommunications closet plus two meters of cable at each end for testing. Limited to a maximum of 90 meters in TIA/EIA 568B.1.


An angular relationship between waves.

Phase Shift

A change in the phase relationship between two alternating quantities.

Photodetector (Receiver)

Converts light energy to electrical energy. The silicon photo diode is most commonly used for relatively fast speeds and good sensitivity in the 0.75 micron to 0.95 micron wavelength region. Avalanche photodiodes (APD) combine the detection of optical signals with internal amplification of photo-current. Internal gain is realized through avalanche multiplication of carriers in the junction region. The advantage in using an APD is its higher signal-to-noise ratio, especially at high bit rates.


Physical (layer of OSI Reference Model). See also Physical Layer.

Physical Layer

The actual portion of a network that is used to physically connect computers of a network and over which the data is transmitted - the cable.


Plastic Insulated Conductor.  Provides strong insulation.


Any device which is capable of transforming a measurable quantity of intelligence (such as sound) into relative electrical signals (e.g., a microphone).




One trillionth of a farad. A micromicrofarad. Abbreviated pF in modern usage or mmF in earlier usage.


A photodetector used to convert optical signals to electrical signals in a receiver. See also Photodetector.


Nominal distance from center-to-center of adjacent conductors within a cable. When conductors are flat, pitch is usually measured from the reference edge of a conductor to the reference edge of the adjacent conductor. Spacing.

Planar Cable

Also referred to as flat and/or ribbon cable. Any cable with two or more parallel conductors in the same plane encapsulated by insulating material.


High polymeric substances, including both natural and synthetic products that are capable of flowing under heat and pressure, called thermoplastics. Unlike rubber and other thermoset compounds, plastics can be remelted and reused.


A chemical added to plastics to make them softer and more flexible.


A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system. A description for a cable that passes the UL 910 CMP flame test requirements.


A male housing with male or female contacts.

Point-to-Point Wiring

Wiring that consists of continuous conductors terminated at each end to circuit destination.


The orientation of a flat cable or a rectangular connector. e.g., for gray flat cable, the colored edge indicating the number one conductor.


A type of synthetic rubber often blended with other synthetic rubbers to improve their properties.


A thermoplastic material having excellent electrical properties. Low dielectric constant, a stable dielectric constant over all frequencies, very high insulation resistance. In terms of flexibility, polyethylene can be rated stiff to very hard, depending on molecular weight and density - low density being the most flexible and the high-density, high-molecular weight formulation being very hard. Moisture resistance is rated excellent.


A substance made of many repeating chemical units or molecules. The term polymer is often used in place of plastic, rubber, or elastomer.


Any of the polymers and copolymers of the ethylene family of hydrocarbons, such as polyethylene and polypropylene.


A thermoplastic similar to polyethylene but stiffer and having a higher softening point (temperature). This material is primarily used as an insulation material. Typically, it is harder than polyethylene. This makes it suitable for thin wall insulations. The dielectric constant is 2.25 for solid and 1.55 for cellular designs.

Polyurethane (PUR)

Broad class of polymers noted for good abrasion and solvent resistance. Can be in solid or cellular form. This thermoplastic material is used primarily as a cable jacket material. It has excellent oxidation, oil, and ozone resistance. Some formulations also have good flame resistance. It is a hard material with excellent abrasion resistance. It has outstanding "memory" properties, making it an ideal jacket material for retractile cords.

Polyvinyl chloride

A general purpose thermoplastic used for wire and cable insulation and jackets.

Portable Cordage

Cable with two or more twisted conductors for flexible applications.  Also called flexible cord.


Plain Old Telephone Service. Sometimes used in discussions of new telephone technologies in which the question of whether and how existing voice transmission for ordinary telephone communication can be accommodated.  For example, DSL and ISDN provide part of their channels for POTS, while using most of their bandwidth for digital data transmission.


Sealing by filling with a substance to exclude moisture.


The amount of work per unit of time. Usually expressed in watts. Power equals the product of voltage and current (P=V*I).

Power Loss

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.




Point-to-Point Protocol.

Precision Video

Video coaxial cables having very tight electrical tolerances in impedance, velocity of propagation, attenuation and structural return loss. Used in high quality applications such as live broadcast in network studios and pre- or post-production facilities.

Premise Cabling

Refers to the entire cabling system used for voice, data, video and power on a user's premise.  For Local Area Networks, the cabling of choice includes unshielded twisted pairs (UTP), fiber optic and coaxial cables.  Of these, the UTP market is the largest, with greatest demand for cables with four pairs that meet certain standards of performance, such as Category 5 and Category 5e.


Primary Rate Interface ISDN.

Propagation Delay

Time required for a signal to pass from the input to the output of a device.

Pseudo Random NRZ

A wave form of binary signals that may be used in a computer system. It is called NRZ, Non-Return to Zero, because the voltage does not return to zero after each bit.


Public Switched Telephone Network.


A current or voltage which changes abruptly from one value to another and back to the original value in a finite length of time. Used to describe one particular variation in a series of wave motions.


Packaging of finished wire or cable.


Polyvinyl chloride (see also).


Polyvinylidene Fluoride.


Quandrature Amplitude Modulation.


Quality of Service.


Quaternary Phase Shift Keying or Quadrature PSK.


A four conductor cable. Also called "star quad".


Symbol for resistance.



Radio Frequency (RF)

Radio Frequency. Includes frequencies from a few kilohertz to several hundred gigahertz. Used to transmit information from point to point over the airwaves or down coaxial cable.


Random Access Memory.

Rated Temperature

The maximum temperature at which an electric component can operate for extended periods without loss of its basic properties.

Rated Voltage

The maximum voltage at which an electric component can operate for extended periods without undue degradation or safety hazard.


Regional Data Center.


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.


An electronic package that converts light energy to electrical energy in a fiber optic system. Also refers to a unit that converts an RF signal to another type of signal (e.g. radio, television). See also Photodetector.


A female housing with male or female contacts.

Reference Edge

Edge of cable or conductor from which measurements are made, such as in flat cable. Sometimes indicated by a thread, identification stripe, or printing. Conductors are usually identified by their sequential position from the reference edge, with number one conductor closest to this edge.


The change in direction (or return) of waves striking a surface. For example, electromagnetic energy reflections can occur at an impedance mismatch in a transmission line, causing standing waves.

Reflection Loss

The part of a signal which is lost due to reflection of power at a line discontinuity.

Refractive Index

The ratio of light velocity in a vacuum to its velocity in the transmitting medium.


Alignment of one object with relation to another. In flat cables it involves aligning conductors with contacts or solder pads. Also called register.


A receiver and transmitter combination used to regenerate an attenuated signal.


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.


An ac circuit condition in which inductive and capacitive reactances 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.

Return Loss

Measure of signal reflections from a cable or device with a fixed, standard reference impedance on the measuring equipment. Expressed in decibels.


Radio Frequency.


Radio Frequency Interference.


Request for Proposals.


RG is the abbreviation for radio guide, a military designation for a coaxial cable, and U stands for universal.


Abbreviation for the three parts of color video signal: red, green and blue. Also refers to multi-coaxial cables carrying these signals.

Ribbon Cable

A flat cable made with parallel round conductors in the same plane. Also referred to as planar and/or flat cable. Any cable with two or more parallel conductors in the same plane encapsulated by insulating material.

Ringing Out

The process of locating or identifying specific conductor paths by means of passing a current through selected conductors.


Modular telecommunications connector.


Return Loss.



Rope Strand

A conductor composed of groups of twisted strands.

Round Conductor Flat Cable (RCFC)

A cable made with parallel round conductors in the same plane.


The path followed by a cable or conductor.


Resource Reservation Protocol.


Real-Time Transport Protocol.

Rubber (Wire Insulation)

A general term used to describe wire insulations made of thermosetting elastomers, such as natural or synthetic rubbers, neoprene, Hypalon, butyl rubber, and others.

RUS 1755.900 (aka PE90)

A specification for fiber optic cables currently in high demand by the telecommunications industry.  Only a handful of U.S. manufacturers can produce fiber optic cables to this specification.  Belden is one of them.


Synchronous Code Division Multiple Access.


Single-pair High bit-rate Digital Subscriber Line.


Society of Automotive Engineers.


A copolymer of styrene and butadiene. Also GR-S or Buna-S. Most commonly used type of synthetic rubber.


Screened Twisted Pair. Premise network cable with an overall foil shield.


Serial Digital Interface.


Symmetric Digital Subscriber Line.


Aluminum Shield.  Sealed Aluminum.


The characteristic of a material that extinguishes its own flame after the igniting flame is removed.


Undulated core with aluminum, polyethylene and a support strand.  For aerial use.

Semi-Solid Dielectric

A coaxial design in which a monofilament of plastic holds the center conductor in place in a hollow plastic tube allowing the remainder of the dielectric to be air. Typical velocities of up to 84% can be achieved in this design.


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. Used for making transistors and diodes.


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.

Serial Digital

Digital information that is transmitted in serial form. SDI informally refers to serial digital television signals that conform to the SMPTE 259M standard. See also Serial Digital Interface.

Serial Digital Interface

Informally refers to serial digital television signals that conform to the SMPTE 259M standard.

Series Circuit

A circuit in which the components are arranged end to end to form a single path for current.

Serve Shield

A metallic shield consisting of several strands of wire, helically wound and laid parallel around a cable core in only one direction, as opposed to the two directions with interleaving of a braid shield.


Pertaining to wire and cable, the outer protective covering, also called jacket, that may also provide additional insulation.


A tape, serve or braid (usually copper, aluminum, or other conductive material) placed around or between electric circuits or cables or their components, to prevent signal leakage or interference.

Shield Coverage

The optical percentage of a cable actually covered by shielding material.

Shield Effectiveness

The relative ability of a shield to screen out undesirable interference or prevent signal leakage out of the cable. Frequently confused with the term shield coverage.

Shield Percentage

The percentage of physical area of a circuit or cable actually covered by shielding material.

Shielded Armored

Types of Shield: Aluminum, Aluminum/Steel, Gopher, and Copper.  Cables that require some sort of shield.


Any visible or audible indication which can convey information. Also, the information conveyed through a communication system.

Signal Conductor

A conductor in a transmission cable or line that carries electrical signals.

Signal to Noise Ratio

Ratio of desired signal to undesired signal (noise) that is often expressed in decibels. Commonly used interchangeably with Attenuation Crosstalk Ratio (ACR) - the difference between attenuation and crosstalk, measured in decibels, at a given frequency. Important characteristic in networking transmission to assure that signal sent down a twisted pair is stronger at the receiving end of the cable than are any interference signals imposed on that same pair by crosstalk from other pairs.


General Electric trademark for a material made from silicon and oxygen. Can be in thermosetting elastomer or liquid form. The thermosetting elastomer form is noted for high heat resistance. This is a very soft thermoset insulation. It has excellent electrical properties plus ozone resistance, low moisture absorption, weather resistance, and radiation resistance. It typically has low mechanical strength and poor scuff resistance.

Single Mode Fiber

A fiber wave guide in which only one mode will propagate. The fiber has a very small core diameter of approximately 8 micro meters. It permits signal transmission at extremely high bandwidths and is generally used with laser diodes.


Unbalanced, such as grounding one side of a circuit or transmission line.


Varying in proportion to the sine of an angle or time function. Ordinary alternating current is sinusoidal.

Skew Rays

A ray that does not intersect the fiber axis. Generally, a light ray that enters the fiber core at a very high angle.

Skin Effect

The tendency of alternating current to travel only on the surface of a conductor as its frequency increases.


Subminiature A connector commonly used in VHF, UHF, and microwave RF applications.


Subminiature B connector snap-mount connector.


Subminiature C connector.

Snake Cable

A name given to individually shielded or individually shielded and jacketed, multi-pair audio cables. Used in the connection of multi-channel line level audio equipment.


Simple Network Management Protocol.


Signal to Noise Ratio (see also).


Synchronous Optical Network.


The device (usually LED or laser) used to convert an electrical information-carrying signal into a corresponding optical signal for transmission by an optical wave guide.


The distance between the centers of two adjacent conductors. Pitch.


The distance between the center of the first conductor and the center of the last conductor in a flat cable.

Spectral Bandwidth

The difference between wavelengths at which the radiant intensity of illumination is half its peak intensity.


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 )

Approximately 2.998 x 10^8 meters per second.


A device that send the signal from one source to two or more receiving devices by allocating a portion of the signal to each receiver (e.g. cable TV splitter). A device that divides a high bandwidth signal into two or more lower bandwidth signals, each carrying a selected frequency range.  Users connected to a DSL line, for example, may have a splitter installed at their home or business to divide the incoming signal into low frequencies to send to their phone and high frequencies for data to the computer.


Structural Return Loss.

Stalpeth (DUCTPIC)

Aluminum steel bonded to the polyethylene jacket.  Helps minimize jacket damage.

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. See also Standing Wave.

Star Quad

Term given to 4-conductor microphone cables where the conductors are spiraled together, which, when connected in an "x" configuration, greatly increases common mode noise rejection.

Static Charge

An electrical charge that is bound to an object. An unmoving electrical charge.

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 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.

Step-index Fiber

An optical fiber in which the core is of a uniform refractive index with a sharp decrease in the index of refraction at the core/cladding interface.


Shielded Twisted Pair(s).

Strain Gauge

A device for determining the amount of strain (change in dimensions) when a stress is applied.


A single uninsulated wire.

Stranded Conductor

A conductor composed of groups of uninsulated wires.


To remove insulation from a cable or wire.

Stripping Groove

The controlled thinning of the lamination between two conductors in a flat cable to allow easy hand separation. Tear feature.

Structural Return Loss

Magnitude of the internal cable reflections, measured in decibels, relative to the actual cable impedance, not the system impedance. Measure of signal reflections caused by the structure of the cable without the additional reflections from any impedance mismatch between the cable and the measuring equipment. Measure of internal cable reflections using a reference impedance in the measuring equipment that is adjusted to the nominal or average impedance of the cable. See also Return Loss


A temporary and relatively large increase in the voltage or current in an electric circuit or cable. Also called transient.


Abbreviation for Super VHS. A video format in which the two parts of the video signal, the chrominance and luminance, are recorded and played back separately providing for better picture quality.  (Not to be confused with S-Video which is a transmission method).

S-Video Transmission method for video in which the two parts of the signal, the chrominance and luminance, are sent on separate transmission lines to provide better picture quality. (Not to be confused with S-VHS which is a videotape recording method).

Sweep Test

Testing a characteristic of a cable or device across a range of frequencies. In cable, it usually implies return loss or structural return loss (see also).


Transmission Control Protocol/Internet Protocol.


Time Division Multiple Access.

Tear Feature

The controlled thinning of the lamination between two conductors in a flat cable to allow easy hand separation.

Teflon (R)

DuPont Company trademark for fluorocarbon resins. (FEP - Fluorinated ethylene-propylene. A thermo-plastic material with good electrical insulating properties and chemical and heat resistance.). (TFE - Tetrafluoroethylene. A thermoplastic material with good electrical insulating properties and chemical and heat resistance.). It is not suitable where subjected to nuclear radiation and does not have good high voltage characteristics. FEP Teflon is extrudable in a manner similar to PVC and polyethylene. This means that long wire and cable lengths are available. TFE Teflon is extrudable in a hydraulic ram type process. Lengths are limited due to amount of material in the ram, thickness of the insulation, and preform size. TFE must be extruded over a silver- or nickel-coated wire. The cost of Teflon is approximately 8 to 10 times more per pound than PVC compounds.


Fluorocopolymer thermoplastic material has excellent electrical properties, heat resistance, chemical resistance, toughness, radiation resistance, and flame resistance.

Temperature Rating

The maximum temperature at which the insulating material or cable may be used in continuous operation without change of its basic properties.

Tensile Strength

The pull stress required to break a bare wire.


Tetrafluoroethylene. 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.


A material which will soften, flow, or distort appreciably when subjected to sufficient heat and pressure. Examples are polyvinyl chloride and polyethylene.


A material which will not soften, flow, or distort appreciably when subjected to heat and pressure. Vulcanizable. Examples are rubber and neoprene.


Telecommunications Industry Association. Body which authored the TIA/EIA 568A "Commercial Building Telecommunications Wiring Standard" in conjunction with EIA.


"Commercial Building Telecommunications Wiring Standard" defines a generic telecommunications wiring system for commercial buildings that will support a multi-product, multi-vendor environment. It also provides direction for the design of telecommunications products for commercial enterprises.


A type of electrical conductor comprised of a number of tiny threads, each thread 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.

Topcoated Wire

Conductor produced by applying a layer of tin over a stranded bare copper conductor holding the strands together allowing easier soldering and preventing the fraying of strands.


Twisted Pair-Physical Medium Dependent.


A device for converting one form of energy to another, such as mechanical energy to 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. Cable shields are normally designed to reduce the transfer of interference - hence, shields with lower transfer impedance are more effective than shields with higher transfer impedance.

Transmission Line

An arrangement of two or more conductors, a coaxial cable, or a waveguide used to transfer signal energy from one location to another.

Transmission Line Cable

Two or more conductors placed within a dielectric material in such a way as to control the electrical characteristics.


The electronic package that converts electrical energy to light energy in a fiber optic system. Also refers to equipment that generates RF or electrical signals for transmission through the air or space or over a transmissions line.

Triad Cable

Cable with three twisted conductors.

Triaxial Cable

A cable construction having a conductor, and two isolated braid shields, all insulated from each other. A coaxial cable with a second braid applied over an inner jacket and an outer jacket applied over the outer braid. Commonly used in television camera systems.

Triboelectric Noise

Noise generated in a shielded cable due to variations in capacitance between the shield and conductors as the cable is flexed.

Trunk Cable

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


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.


TV Receive Only.


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.

Twinax Cable

Cable with two twisted conductors with established electrical properties (one pair=twinax).

Twisted Pair

Two lengths of insulated conductors twisted together.  The traditional method for connecting home and many business computers to the telephone company.  Gets its name because two insulated copper wires are twisted together, both of which are needed for each connection.  In commercial environments, performance of data transmission can be improved by adding a composite tape to the wire.  This is known as shielded twisted pair.

Two pair premise wiring

Refers to the two pairs of voice grade (low bandwidth) twisted pair wire installed in most homes since the 1950s.  The extra pair makes it possible for you to add another line when you need it.


Ultra High Frequency. International Telecommunication Union designation for the 300-3000 MHz band of frequencies.


Underwriters Laboratories. A nonprofit organization which tests and verifies construction and performance of electronic parts and equipment, including wire and cable.


Unsoldered Mechanical Protection - Additional steel and polyethylene over inner polyethylene jacket.  Provides additional mechanical protection.

Unbalanced Line

A transmission line in which voltages on the two conductors are unequal with respect to ground. A coaxial cable is a common type of unbalanced line.


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(s).


Volt (see also).


Volt-ampere. Measure of apparent power in a reactive circuit found by multiplying the voltage by the current.


Variable Constellation/Multi-Tone Modulation.


Very high bit rate Digital Subscriber Line.

Velocity of Propagation (VP)

The transmission speed of electrical energy in a length of cable compared to speed of light in free space. Usually expressed as a percentage.


Very High Frequency. International Telecommunication Union designation for the 30-300 MHz band of frequencies.


Abbreviation for Video Home System. VHS is a trademark of Panasonic, Inc.


Pertaining to picture information in a television system.


Very Low Frequency. International Telecommunications Union designation for the 3-30 kHz band of frequencies.


A unit of electromotive force.


Electrical potential of electromotive force expressed in volts.

Voltage Drop

The voltage developed across a component or conductor by the current flow through the resistance or impedance of the component or conductor.

Voltage Rating

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

Voltage Standing Wave Ratio

Ratio of maximum voltage of the standing wave to the minimum voltage of the standing wave. See also Standing Wave Ratio.


Voltage Standing Wave Ratio.


A flammability rating established by Underwriters Laboratories for wires and cables that pass a specially designed vertical flame test, formerly designed FR-1.


Symbol for watt or wattage.

Wall Thickness

The thickness of an insulation or jacket.


Wide Area Network.


A unit of electrical power.

Wave Form

A graphical representation of a varying quantity. Usually, time is represented on the horizontal axis, and the current or voltage value is represented on the vertical axis.


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


Wireless Communications Service.


A conductor, either bare or insulated.


Really a misnomer.  Belden makes a variety of cables needed to build the transmitting infrastructure required to support "wireless" devices.  Wireless is a technology that allows a device (phone, pager or satellite dish) to be unconnected from the transmission point of a voice, video or data signal.  The transmission infrastructure required to support such wireless devices is a wired platform of transmission towers and stations that communicate point to point and to telephone central offices.


Symbol for reactance.


Crosslinked polyethylene is a thermoset and is crosslinked by radiation, thermally, or by moisture. XLPE offers a wide range of operating temperatures, excellent deformation, abrasion, and flame resistance. XLPE can be formulated with halogenated or non-halogenated flame retardant packages. Some grades are also rated XHHW-2 which offers excellent wet electrical properties.


A multi-pin audio connector (typically 3 pins) used in microphone, line level and snake cable audio connections.


Expanded Polyethylene-Polyvinyl Chloride.  Fire retardant.


Symbol for impedance