CableDataSheet, Cable and Wire Technical Consulting Service

O

Octet  - In packet-switched networks, a grouping of eight bits; similar but not identical by byte.


OD  - Outside diameter.



ODBC (open database connectivity)  - ODBC is a widely accepted application programming interface (API) for databases using structured query language (SQL).



ODI (open data link interface)  - Novell's media-and-protocol-independent communications specification providing a standard interface that allows transport protocols to share a network interface card without conflict.



OEM  - Original equipment manufacturer.



OFDM  - Orthogonal frequency division multiplexing.



OFDM  - Orthogonal frequency division multiplexing.



OFHC  - Oxygen-free high-conductivity copper.



OFL (overfilled launch)  - Standard for MMF when used with LEDs (uses 100 percent of core).



Ohm  - (W) The electrical unit of 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 where E is voltage, I is current and R is resistance.



OID  - Object ID.



Oil aging  - Cable aged in an accelerated manner by placement in an oil bath and heated to a preset temperature for a stated time.



OLT (optical line terminator)  - In EFM applications, an aggregation device, usually located at the CO, that uses passive optical splitting from one fiber from a CO Ethernet switch to individual fibers feeding homes.



OM3  - ISO/IEC 11801 specification for laser optimized multimode fiber type for 10 Gbps applications.



Online computer  - A computer used for online processing.



ONT (optical network terminal)  - Fiber terminal outside a residence in FTTH application. Conversion point from fiber to copper.



ONU (optical network unit)  - In an EPON system the ONU provides the functionality to connect the fiber owned by the service provider to the media in the residence.



Open architecture  - An architecture that is compatible with hardware and software from any of many vendors. Contrast with CLOSED ARCHITECTURE.



Open cell  - Foamed or cellular material with broken cell walls. Air fills in the spaces in the material. Usually softer and less expensive than closed cell material.



Open circuit  - A break in an electrical circuit so that there can be no current flow.



Optical conductor  - Materials that offer a low optical attenuation to transmission of light energy.



Optical connector  - Connector designed to connect and disconnect either single or multiple optical fibers repeatedly. Optical connectors are used to connect fiber cable to equipment and interconnect cables. (Examples are: ST, SC, SMA, etc.)



Optical cross-connect - A cross-connect unit used for circuit administration and built from modular cabinets. It provides for the connection of individual optical fibers with optical fiber patch cords.



Optical encoder  - A device whose position is determined by a photoelectric device and converted to an electrical data output.



Optical fiber connector  - See OPTICAL CONNECTOR.



Optical fiber duplex adapter  - A mechanical media termination device designed to align and join two duplex connectors.



Optical fiber duplex connection  - A mated assembly of two duplex connectors and a duplex adapter.



Optical fiber duplex connector  - A mechanical media termination device designed to transfer optical power between two pairs of optical fibers.



Optical fiber  - Any filament or fiber, made of dielectric materials that is used to transmit light signals; optical fiber usually consists of a core, which carries the signal and cladding, a substance with a higher refractive index than the core, which surrounds the core and serves to reflect the light signal. See also FIBER OPTICS.



Optical interconnect  - An interconnection unit used for circuit administration and built from modular cabinets. It provides interconnection for individual optical fibers, but unlike the optical cross connect panel, it does not use patch cords. The optical interconnect provides some capability for routing and rerouting circuits, but is usually used where circuit rearrangements are infrequent.



Optical splice  - A fiber optic splice provides the means by which two or 24 fiber optic cable ends are permanently joined together. Two types of optical splices are fusion and mechanical.



Optical transceiver  - An optical device which both transmits and receives data over optical fiber.



Optical waveguide  - A fiber used for optical communications. Analogous to a waveguide used for microwave communications.



Optimization  - The procedure used in the design of a system to maximize or minimize some performance index.



ORL  - Optical return loss.



OS/2  - An operating system developed by IBM, largely relegated to niche uses and virtualization applications.



Oscillatory surge  - A surge that includes both positive and negative polarity values.



Oscilloscope  - Test instrument for visually showing the changes in a varying voltage by means of a line made on a fluorescent screen using the deflection of a beam of cathode rays.



OSHA (Occupational Safety and Health Act)  - Federal Law #91-596 or 1970 charging all employers engaged in business affecting interstate commerce to be responsible for providing a safe working place. It is administered by the Department of Labor. OSHA regulations are published in Title 29, Chapter XVIII, Part 1910 of the CFR and the Federal Register.



OSI (open systems interconnection)  - The OSI reference model for a logical structure for network operations standardized with the ISO; a 7-layer network architecture being used for the definition of network protocol standards to enable any OSI-compliant computer or device to communicate with any other OSI-compliant computer or device for an exchange of information.



OSMOSIS  - The diffusion of fluids through membranes.



OTDR (Optical Time Domain Reflectometer)  - An instrument that locates faults in optical fibers or infers attenuation from backscattered light measurements.



Out gassing  - Dissipation of gas from a material.



Outdoor termination  - A cable termination intended for use where it is not protected from direct exposure to either solar radiation or precipitation.



Outlet box, telecommunications  - A metallic or nonmetallic box mounted within a wall, floor or ceiling and used to hold telecommunications outlets, connectors or transition devices.



Outlet/connector, telecommunications  - A connecting device in the work area on which horizontal cable terminates.



Out-of-band signaling - A method of signaling which uses a frequency that is within the pass band of the transmission facility, but outside of a carrier channel normally used for information transmission.



Output  - The useful power to signal delivered by a circuit or device.



Overall diameter  - Finished diameter of a wire or cable.



Overcoat conductor  - A stranded conductor made from individual strands of tin-coated wire stranded together and then given an overall tin coat.



Overlap  - The amount the trailing edge laps over the leading edge of a spiral tape wrap.



Oxygen index  - A test to rate flammability of materials in a mixture of oxygen and nitrogen. More formally referred to as limiting oxygen index (LOI).



Ozone  - An extremely reactive form of oxygen, normally occurring around electrical discharges and present in the atmosphere in small but active quantities. In sufficient concentrations it can break down certain insulations.

P

PABX (private automatic branch exchange) - Equipment originally used as a means of switching telephone calls within a business site and from the site to outside lines. Can also be used for low speed transmission of data, in addition to voice.


Packet - A collection of bits that contain both control information and data. The basic unit of transmission in a packet-switched network, control information is carried in the packet, along with the data, to provide for such functions as addressing, sequencing, flow control and error control at each of several protocol levels. A packet can be of fixed or variable length, but generally has a specified maximum length.


Packet format - The exact order and size of the various control and information fields of a packet, including header, address and data fields.


Packet overhead - A measure of the ratio of the total packet bits occupied by control information to the number of bits of data, usually expressed as a percent.


Packet switching - A data communications technique in which data is transmitted by means of addressed packets and a transmission channel is occupied for the duration of transmission of the packet only. The channel is then available for use by packets being transferred between different data terminal equipment.


PACS - Physical access control system.


Pad - A passive attenuation device used to reduce a signal's amplitude.


PAD (packet assembler/disasssembler) - In a X.25 packet-switched network, a device used to interface non- X.25 devices to an X.25 network; it may be synchronous or asynchronous, single or multiple channel.


Pair - Two insulated wires of a single circuit associated together; also known as a "balanced" transmission line.


PAL (phase alternating line) - A non-NTSC video format used mainly in Europe, Australia, China, India and many countries in Africa and the Middle East. It has6 25 lines of resolution with 50 fields per second or 25 frames per second.


PAM - Pulse amplitude modulation.


Parallel circuit - A circuit in which identical voltage is presented to all components, and the current divides among the components according to the resistances or the impedances of the components.


Parallel stripe - A stripe applied longitudinally on a wire or cable parallel to the axis of the conductor.


Parallel transmission - A technique that sends bits simultaneously over a separate lines; normally used to send data a byte (eight bits over eight lines) at a time to a high-speed printer or other locally attached peripheral. Contrast with SERIAL TRANSMISSION.


Parity, parity check - Addition of overhead bits to ensure that the total number of 1s in a grouping of bits is either always even for even parity or always odd for odd parity. This permits detection of single errors. It may be applied to characters, transmission blocks or any convenient bit grouping.


Partial discharge (Corona) Extinction voltage - The voltage at which partial discharge (corona) is no longer detectable on instrumentation adjusted to a specific sensitivity, following the application of a specified higher voltage.


Passive - A non-powered element of a system.


Patch cable - In the IBM cabling system, a length of Type 6 cable with data connectors on both ends.


Patch cord - A flexible piece of electrical cord terminated at both ends with plugs, used for inter-connecting circuits on a patch board.


Patch panel - A terminating enclosure for connecting cables. See DISTRIBUTION PANEL.


Path loss - Actual signal attenuation from point of transmission to point of reception.


Pathway - A facility for the placement of telecommunications cable.


Payoff - The process of feeding a cable or wire from a bobbin, reel or other package. The payoff is the source reel. Wire is fed from a payoff reel onto a take-up reel.


PBDE – (Polybrominated diphenyl ether). A class of flame retardants sometimes used in wire and cable products. PBDEs are generally banned by European Union RoHS regulations.


PBX (private branch exchange) - A manual, user-owned telephone exchange. Sometimes used in a general sense to include both PBXs and PABXs.


PC - Personal computer.


PCB - Printed circuit board. Also referred to as PWB (printed wiring board) to distinguish this usage from the chemical usage (polychlorinated biphenyls–persistent organic pollutants that are banned in many countries).


PCM (pulse code modulation) - A modulation technique used to convert analog voice signals into digital form. Used for voice multiplexing on T1 circuits.


PCMCIA - Personal Computer Memory Card International Association.


PCP - (Neoprene) Polychloroprene.


PDN (public data network) - A packet switched or circuit switched network available for use by many customers. PDNs may offer value-added services at a reduced cost because of communications resource sharing, and usually provide increased reliability due to built-in redundancy.


PDS - See PREMISES DISTRIBUTION SYSTEM.


PDU - Power distribution unit.


PE - Polyethylene.


Peak - The maximum instantaneous value of a varying current or voltage. Also called crest.


Peak-to-peak - The amplitude difference between the most positive and the most negative excursions of a signal.


Peek - Poly ether ether ketone. A colorless organic thermoplastic used for its robustness.


Peel strength - The force necessary to peel a flexible member from another member that may be either flexible or rigid.


Percent conductivity - The ratio of the resistivity of the International Annealed Copper Standard (IACS) at 20°C to the resistivity of a material at 20°C, expressed in percent. Results are calculated on a weight basis or volume basis and so specified.


Percent plating - Quantity of plating on a conductor expressed as a percentage by weight.


Percentage conductivity - Conductivity of a material expressed as a percentage of that of copper.


Peripheral - Any device used to process data for entry into or extraction from a computer.


Personal computer - A microcomputer with an end-user-oriented application program (used by data processing professionals and non-professionals alike) for an assortment of functions.


PFA (Perfluoroalkoxy) - Teflon is the DuPont trademark for perfluoroalkoxy.


Phase - The location of a position on a waveform of an alternating current, in relation to the start of a cycle. Measured in degrees with 360 corresponding to one complete cycle.


Phase modulation - One of three basic ways to add information to a sine wave signal; the phase of the sine wave, or carrier, is modified in accordance with the information to be transmitted. With only discrete changes in phase, this technique is known as phase shift keying (PSK).


Phase sequence - The order in which successive members of a periodic wave set reach their positive maximum values: a) zero phase sequence, no phase shift; b) plus/minus phase sequence, normal phase shift.


Phase shift - A change in the phase relationship between two alternating quantities. The phase angle between the input and output signals of a system.


Photovoltaic wire (PV WIRE) - A UL cable type. 600 V, 1,000 V, 2,000 V insulated, stranded single conductor wire used to connect photovoltaic electricity generating panels to each other and to collection, distribution and utilization equipment.


Phy - The physical layer device, a circuit block that includes a PMD (physical media dependent), a PMA (physical media attachment), and a PCS (physical coding sub layer).


PIC - Polyethylene insulated cable.


Pick - Distance between two adjacent crossover points of braid filaments. The measurement in picks per inch indicates the degree of coverage.


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


Pico - Prefix meaning one-millionth of one-millionth (10-12).


Picofarad - One-millionth of one-millionth of a farad. A micro microfarad or picofarad (abbreviation pf).


Pigtail wire - Fine stranded, extra flexible, rope lay lead wire attached to a shield for terminating purposes.


PILC cable - Paper insulated, lead covered. Old cable style present in many urban distribution networks. Most are scheduled for replacement due to lead content and age.


PIMF - Pairs in metal foil. Also referred to as S/FTP cable.


Pin assignment - A predetermined relationship between the terminals in a connector and the conductors in a cable that specifies the terminals to which each conductor is to be terminated.


Pinhole lens - Lens used for applications where the camera or lens must be hidden. Front of lens has a small opening to allow the lens to view an entire room through a small hole in a wall.


Pin - Passive infrared.


Pitch - In flat cable, the nominal distance between the index edges of two adjacent conductors.


Pitch diameter - Diameter of a circle passing through the center of the conductors in any layer of a multi-conductor cable.


PIV - Personal identity verification.


Planetary twister - A cabling machine whose payoff spools are mounted in rotating cradles that hold the axis of the spool in a fixed direction as the spools are revolved so the wire will not kink as it is twisted.


Plastic - High-polymeric substances, including both natural and synthetic products, but excluding the rubbers that are capable of flowing under head and pressure.


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


Plated hole - A hole with walls that have been plated with conductive material to provide an electrical connection between the conductive patterns on both sides of a printed circuit or an anchor for soldering an inserted wire.


PLC - Programmable logic controller. A type of industrial control system.


Plenum- The air return path of a central air handling system, either ductwork or open space over a suspended ceiling.


Plenum cable - 1. A cable that is UL Listed as having adequate fire resistance and low smoke producing characteristics for installation without conduit in ducts, plenums and other spaces used for environmental air, as permitted by NEC Articles 725-2(b) and 800-3(b). 2. Cable specifically designed for use in a plenum, the space above a suspended ceiling used to circulate air back to the heating or cooling system in a building. Plenum cable has insulated conductors often jacketed with Teflon or Halar to give them low flame - and low smoke – producing properties.


PLP - Packet layer protocol.


PLTC (power limited tray cable) - Rated 300 volts.


Plug - The part of the two mating halves of a connector that is movable when not fastened to the other mating half.


Ply- The number of individual strands or filaments twisted together to form a single thread.


PMD - 1. Physical medium dependant. The portion of the physical layer (PHY) responsible for
interfacing to the transmission medium, the physical media dependent sub layer is responsible for transmission. 2. Polarization mode dispersion.


PoE (Power over Ethernet) - A system to transfer electrical power, along with data, to
remote devices over standard twisted-pair cable in an Ethernet network. Defined by the
IEEE 802.3af standard.


POF (polymer optical fiber) - One of the media projected to become the heart of an automotive LAN. Current experimentation and technological agreements between key companies may result in technological advancements to ultimately herald the introduction of LANs in transportation vehicles. The POF media would become the communications backbone of the vehicle.


Point-to-point connection - See LINK.


Point-to-point wiring - An interconnecting technique wherein the connections between components are made by wires routed between connecting points.


Polar transmission - See BIPOLAR TRANSMISSION.


Polarization - (1) The orientation of a flat cable or a rectangular connector. (2) Orientation of the electric field in an electromagnetic wave. Common characteristic of antennas.


Polishing - Act of smoothing ends of optical fibers to an "optically smooth" finish, generally using abrasives.


Polyamide - The chemical name for nylon.


Polyaramid - Generic name for Kevlar. Sometimes also referred to as a ramid fiber.


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


Polychloroprene - See NEOPRENE.


Polyester - Polyethylene terephthalate, used extensively as a moisture-resistant cable core wrap. Mylar is DuPont's trademark for polyester.


Polyethylene - A thermoplastic material having excellent electrical properties.


Polyhalocarbon - A general name for polymers containing halogen atoms. The halogens are fluorine, chlorine, bromine and iodine.


Polyimide - A relatively high-temperature plastic developed for use as a dielectric or jacketing material. Kapton is DuPont's trademark for polyimide.


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


Polymer optical fiber - One of the media projected to become the heart of an automotive LAN. Current experimentation and technological agreements between key companies may result in technological advancements to ultimately herald the introduction of LANs in transportation vehicles. The POF media would become the communications backbone of the vehicle.


Polyolefins - A family of plastics including cross-linked polyethylene and various ethylene copolymers.


Polypropylene - A thermoplastic similar to polyethylene but stiffer and having higher softening point (temperature).


Polyurethane - Broad class of polymers noted for good abrasion and solvent resistance. Can be solid or cellular form.


Polyvinyl chloride (PVC) - A general purpose thermoplastic used for wire and cable insulations and jackets.


Porosity - Generally defined as the percentage of space occupied by voids in an insulation cross section.


Port - 1. An entrance to or exit from a network; an access point ford at an entry or exit. 2. A computer interface capable of attaching to a modem for communicating with a remote terminal.


Port concentrator, port concentration - A device that allows several terminals to use a single computer port; a concentrator link in which the port concentrator simplifies the software Demultiplexing used in lieu of the Demultiplexing normally performed by the computer-site concentrator.


P.O.S. - Abbreviation for point-of-sale (e.g., a cash register station).


Position coding - Identification of conductors by their location, possible only when conductors are located in assigned positions with relation to each other throughout the entire length of a cable.


Positive sequence impedance - The electrical impedance of a three-phase power cable during normal operation. A cable parameter used by electrical system engineers to calculate voltage drop. "Positive sequence" refers to the phase relationship of the currents in the conductors.


Post equalization - A method of equalizing the signal that comes from the customer equipment to the D4 channel bank. Equalization provides a near-linear level for all frequencies in the voice-frequency band.


Pots - Acronym for plain old telephone service.


Potting - Sealing by filling with a substance to exclude moisture.


Power - The amount of work per unit of time. Usually expressed in watts and equal to I2R.


Power cables - Cables of various sizes, constructions and insulations, single or multi-conductor, designed to distribute primary power to various types of equipment.


Power factor - The cosine of the phase difference between current and applied voltage.


Power loss - The difference between the total power delivered to a circuit, cable or device, and power delivered by that device to a load.


Power ratio - The ratio of the power appearing at the load, to the input power. Expressed in dB, it is equal to 10 log10 (Px/P1) where P1 is input power and P2 is the power at the load.


PPE - Polypropylene ethylene.


PPP (point-to-point protocol) - PPP is the Internet standard for transmission of IP packets over serial lines. PPP supports a sync and sync lines.


PPS - Pictures per second. Sometimes referred to as ips (images per second).


PPTP - Point to point tunneling protocol.


Preamble - An alternating sequence (1, 0, 1, 0. . .) signaling the beginning of a packet.


Prebond - Stranded wire that has been fused, topcoat tinned or overcoat tinned.


Premises distribution system - The transmission network inside a building or group of buildings that connects various types of voice and data communications devices, switching equipment and other information management systems together, as well as to outside communications networks. The system consists of all the transmission media and electronics, administration points, connectors, adapters, plugs and supports hardware between the building's side of the network and the terminal equipment required to make the system operational.


Premises network - See CABLE SYSTEM.


Premolded splice - A joint made of pre-molded components assembled in the field.


Preposition lenses - Zoom lenses that utilize a variable-resistor (potentiometer) to indicate zoom or focus position to the lens controller. After initial setup, this allows the operator to view different preset areas quickly without having to readjust the zoom and focus each time.


Primary - The transformer winding that receives the energy from a supply current.


Primary insulation - The first layer of nonconductive material applied over a conductor, whose prime function is to act as electrical insulation.


Printing wiring - A printed circuit intended to provide point-to-point electrical connections.


Private line - See LEASED LINE.


Private network, private line - Telecommunications network owned by the customer or reserved for exclusive use by the customer. Same as leased line.


Production (routine) tests - Tests made on components or subassemblies during production for the purpose of quality control.


PROM (programmable read-only memory) - Permanently stored data in a nonvolatile semiconductor device.


Propagation delay - The transmit time through a link, network, system or piece of equipment.


Propagation delay skew - The difference in delay between the fastest and slowest pairs within the same cable sheath.


Propagation time - Time required for a wave or pulse to travel between two points on a transmission line.


Propagation velocity - The velocity of the propagation of a wave or pulse along a transmission path.


Proprietary LAN - A LAN that runs the equipment of only one manufacturer.


Protective covering - A field-applied material to provide environmental protection over the splice or housing, or both.


Protocol - A set of procedures for establishing and controlling communications.


Protocol analyzer - A test unit that provides compatibility with leading integrated network management systems to optimize troubleshooting and centralized performance analysis of enterprise networks.


Protocol converters - Devices that transform one protocol to another in order to provide compatibility between systems using different protocols. In ISN, the Model 4271 Protocol Converter translates ASCII data to bisynchronous data and, in reverse, converts bisynchronous data to ASCII data. The model 4276 performs a similar translation between ASCII data and SNA/SDLC protocol.


Proximity effect – Non-uniform current distribution over the cross-section of a conductor caused by the variation of the current in a neighboring conductor.


PSAACRF - Power sum insertion loss to alien crosstalk ratio far-end. A computation of signal coupling from multiple pairs of disturbing channels, to a disturbed pair in another channel measured at the far-end and relative to the received signal level in the disturbed pair at the far-end. Also referred to as power sum alien equal-level far-end crosstalk (PSAELFEXT).


PSANEXT - Power sum alien near-end crosstalk. A computation of signal coupling from multiple near-end disturbing channel pairs into a disturbed pair of a neighboring channel or part thereof, measured at the near-end.


PSAFEXT - Power sum alien far-end crosstalk. A computation of signal coupling from multiple near-end disturbing channel pairs into a disturbed pair of a neighboring channel or part thereof, measured at the far-end.


PSN (packet switching network) - A network that enables external computers and terminals to communicate with other computers linked to the network. PSN uses packet switching to transmit data. Connections to PSN are governed by a series of recommendations known collectively as X.25.


PSNEXT - Power sum near-end crosstalk. A computation of the unwanted signal coupling from multiple transmitters at the near-end into a neighboring (non-energized) pair measured at the near-end.


PT - Thermostat cable with solid conductor, individual insulation, twisted together.


PTFE (TFE Teflon) - Polytetrafluoroethylene.


PTSS - Passive transmission subsystem.


PTT (post telephone and telegraph authority) - The government agency that functions as the communications common carrier and administrator in many areas of the world.


Pulling eye - A device attached to a conductor to pull cable into or from a duct.


Pulse - A current or voltage which changes abruptly from one value to another and back to the original value in a finite length of time.


Pulse cable - A type of coaxial cable constructed to transmit repeated high voltage pulses without degradation.


Pulse width modulation - Modulating a pulse train by varying the pulse width in proportion to the modulating signal's significant characteristic.


Punch-down block - A 2-foot piece of metal and plastic that allows you to connect telephone wiring coming from two remote points. Also called a 66-block or quick-connect block.


PUR - Polyur ethane.


PVC (permanent virtual circuit) - In a packet-switched network, a fixed virtual circuit between two users; no-call setup or clearing procedures are necessary; the PDN equivalent of a leased line; contrast with switched virtual circuit.


PVC (polyvinyl chloride) - A common insulating and jacketing material used on cables.


PVC-I - A MIL-DTL-17 coax jacket type. A black polyvinyl chloride with excellent weathering and abrasion properties, but is a contaminating type and will cause cable attenuation to increase with age. Can be used for direct burial.


PVC-II - A MIL-DTL-17 coax jacket type. A gray polyvinyl chloride material which is semi-non-contaminating.


PVC-IIA - A MIL-DTL-17 coax jacket type. A black or gray polyvinyl chloride material that is non-contaminating. It has good weathering and abrasion-resistant properties and can be used for direct burial.


PVDF - Kynar, Atochem trademark for polyvinylidene fluoride.


PWB - Printed wiring board. Replacing PCB in common usage to avoid confusion with chemical PCBs.


PYROMETER - See THERMOCOUPLE.

Q

Q band - The band of frequencies between 36 and 46 gigahertz.


QoS - Quality of service.


QPL - A Qualified Products List issued by the U.S. government.


QPSK (quadrature phase shift keying) - It is a digital frequency modulation technique used for sending data over coaxial cable networks.


Quad - A series of four separately insulated conductors, generally twisted together in pairs.

R

R - Symbol for electrical resistance or resistor.


Raceway - A channel for holding electric wires or cables.


Rack - 1. Same as cabinet. 2. The vertical or horizontal open support usually made of aluminum or steel that is attached to a ceiling or wall. Cables are laid in and fastened to the rack.


Rack mount - Designed to be installed in a cabinet.


Radio frequency - The frequencies in the electromagnetic spectrum that are used for radio communications. A band of frequencies between 10 kilohertz and 100 gigahertz.


RADIUS (remote authentication dial-in user service) - A service to authenticate dial-in users on a LAN (RADIUS server).


RAID (redundant array of inexpensive disks) - A term used to describe a storage systems' resilience to disk failure through the use of multiple disks and by the use of data distribution and correction techniques.


RAM (random access memory) - Volatile memory.


Random interlace - A scanning technique commonly used in CCTV systems in which there is no external control over the scanning process. There is no fixed relationship between adjacent lines and successive fields.


Random winding - A winding in rotating equipment wherein wires do not lie in an even pattern.


Range finder - Used to determine the focal length needed and what the picture will look like on the monitor. The user looks through the device and adjusts the range finder to the desired picture. Numbers on the outside of the range finder indicate the focal length needed.


Raster - The rectangular pattern of scanning lines upon which the picture is produced. The illuminated face of the TV monitor without the video information present.


RBOC - Regional Bell Operating Company.


REA (Rural Electrification Agency) - A federally supported program to provide electrical service to rural area. Now referred to as Rural Utilities Services (RUS).


REACH (REGISTRATION, EVALUATION AND AUTHORIZATION OF CHEMICALS) - A European community regulation on the safe use of chemicals. Companies selling into the European market are required to provide compliance information to their downstream users. Compliance requires the investigation of the supply chain for the presence of certain chemicals called SVHCs (substances of very high concern). REACH began in 2008. Chemicals will be added for a period of several years.


Reactance - The opposition offered an alternating electron flow by a capacitance or inductance. 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. The imaginary part of impedance.


Real-time system - An online computer that generates output nearly simultaneously with the corresponding inputs. Often, a computer system whose outputs follow by only very short delay its inputs. Also called transaction processing.


Recovered diameter - Diameter of shrinkable products after heating has caused it to return to its extruded diameter.


Red plague - A powdery, brown-red growth sometimes found on silver-coated copper conductors and shield braids.


Redraw - The consecutive drawing of wire through a series of dies to reach a desired wire size.


Redundancy - The inclusion of extra assemblies of circuits within the UPS, with provision for automatic switchover from a failing assembly or circuit to its operational counterpart.


Reel - A revolving flanged device made of plastic, wood or metal, used for winding flexible cable. Also called a spool.


Reference edge - See INDEX EDGE.


Reference junction - The junction of a thermocouple that is at a known reference temperature. Also known as the "cold" junction, it is usually located at the EMF measuring device.


Reflected light - The scene brightness or the light being reflected from a scene. Usually it represents 5 to 95 percent of the incident light, and it is expressed in foot-lamberts.


Reflection - 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 that is lost to reflection of power at a line discontinuity.


Reflow soldering - The process of connecting two solder-coated conductive surfaces by re-melting of the solder to cause fusion.


Refraction - The bending of light waves or rays as they go from one material to another due to the difference in velocities in the materials.


Reinforced sheath - The outer covering of a cable that has a reinforcing material, usually a braided fiber, molded in place between layers.


Reliability - The probability that a device will function without failure over a specified time period of amount of usage.


Remote alarms - Alarm indications or status displayed at the distant end of a foreign location to the transmission line.


Repeater – (1) A device used to extend the length, topology or interconnectivity of the physical network medium beyond the limits imposed by a single segment. Repeaters perform the basic actions of restoring signal amplitude, waveform and timing applied to normal data and collision signals. (2) In an ISN system, a module in every information interface carrier that synchronizes bus transmissions throughout the packet controller by repeating on each IIC the timing and transmission signals generated by the clock module in the control and interface unit.


Resin - A solid or semisolid organic substance, originally of plant origin but largely synthesized now. Resins are broadly classified as thermoplastic or thermoset according to whether they soften or harden with the application of heat.


Resistance - In DC circuits, the opposition a material offers to current, measured in ohms. In AC circuits, resistance is the real component of impedance, and may be higher than the value measured at DC.


Resistive conductor - A conductor with high electrical resistance.


Resistivity - A material characteristic opposing the flow of energy through the material – expressed as a constant for each material - is affected by temper, temperature, contamination, alloying, coating, etc. The ability to resist the flow of electrical current either through the bulk of the material or on its surface. The unit of volume resistivity is the ohm-cm. The unit of surface resistivity is ohms/m2.


Resistor - An electronic component designed to have a specific value of resistance.


Resistor color code - A method of indicating resistance value and tolerance. The first color represents the first significant figure of the value. A second color represents the second significant figure and the third is the multiplier or the number of zeros that follow two significant figures. When there is a fourth color band, it indicates the tolerance.


Resolution - A measure of the ability of a camera or television system to reproduce detail. That is the number of picture elements that can be reproduced with good definition. It is a factor of the pickup device or the TV CRT characteristics and the video signal bandwidth.


Resonance - An AC circuit condition in which inductive and capacitive reactance interact to cause minimum or maximum circuit impedance.


Retained image (image burn) - A change produced in or on the target of the pickup device that remains for a large number of frames after the removal of a previously stationary light image and that yields a spurious electrical signal that corresponds to that light image.


Retractile cord - A cord having specially treated insulation or jacket, so it will retract like a spring. Retract ability may be added to all or part of cord's length.


Return - Inbound direction; toward the headend.


Return loss - A measure of the degree of impedance mismatch between two impedances. It is the ratio, expressed in dB, of the amplitude of a reflected wave to the amplitude of the main wave at the junction of a transmission line and terminating impedance.


Return wire - A ground wire or the negative wire in a direct-current circuit.


Reverse direction - The direction on the cable from the modem to the headend.


Rew - A 600 volt Canadian wire type covered by CSA standards. Made with thermoset insulation.


REX (request to exit) - Sometime referred to as RQE.


RF (radio frequency) - Uses electromagnetic waveforms used for transmission, usually in the megahertz (MHz) range. Electromagnetic waves are usually transmitted between 500 kHz and 300 GHz.


RF modem (radio frequency modem) - Device used to convert digital data signals to analog signals (and from analog to digital) then modulate/demodulate them to/from their assigned frequencies.


RFI (radio frequency interference) - The disruption of radio signal reception caused by any source that generates radio waves at the same frequency and along the same path as the desired wave.


RFID (radio frequency identification) - A type of wireless access control technology between a proximity card and a reader. The most common is the 125 kHz frequency used with proximity cards. There is also a 13.56 MHz version that is a contactless smart card credential.


RG (residential gateway) - A network interface device that provides a means to access a service delivered to the home.


RG-U - RG is the military designation for coaxial cable, and U stands for general utility.


RG-58U 50-ohm coaxial cable assembly - Used as Ethernet thinnet trunk cable and many other 50-ohm compatible systems. True Ethernet has a standard center conductor.


RG-59U 75-ohm coaxial cable assembly - Used as interconnect data equipment for the Wang system CATV, and all other compatible data, voice, baseband and broadband video systems.


RG-62U 93-ohm coaxial cable assembly - Used extensively on the IBM cabling system and all other compatible systems.


RHH - Rubber-insulated, heat-resistant wire, rated 90°C in dry and damp locations. A UL cable type.


RHW - Rubber-insulated building wire, heat and moisture-resistant, 75°C dry or wet. A UL cable type.


RHW-2 - Rubber-insulated building wire, heat and moisture-resistant, 90°C dry or wet. A UL cable type.


RI - Ring in.


Ribbon cable - A flat cable of individually insulated conductors lying parallel and held together by means of adhesive or an extruded polymer web.


Ribbon fiber cable - A cable that accommodates 1 to 12 ribbons, each ribbon having1 2 fibers for a cable size range of 12 to 144 fibers. Ribbon cables are designed for use in large distribution systems where small cable size and high pulling strength are important.


Ridge marker - One or more ridges running laterally along the outer surface of a plastic insulated wire for purposes of identification.


Rigid coaxial cable - Nonflexible coaxial cable, usually a metal tube armored coaxial cable. Sometimes called "hardline."


Ring – (1) In LAN technology, a closed loop network topology; contrast with bus and star. (2) One of the two wires in a telephone circuit. The ring wire usually has a negative battery potential relative to the tip wire. (3) A network topology in which stations are connected to one another in a closed logical circle. Typically, access to the media passes sequentially from one station to the next by means of polling from a master station, or by passing an access token from one station to another.


Ring-down circuit - A tie line connecting phones in which picking up one phone automatically rings the other phone.


Ring in - On an access unit, the transmit or output receptacle.


Ringing out - Locating or identifying specific conductive paths by passing current through selected conductors.


Ring tongue - A solder less terminal that connects wire to a stud.


Rip cord - Two or more insulated conductors in a parallel configuration that may be separated to leave the insulation of each conductor intact.


RISC (reduced instruction set computer) - The IBM RISC System/6000 system units are a second generation of computers using the RISC architecture. They offer a full range of multiuser, multitasking, open-architecture workstations and servers.


Rise time - The time it takes the voltage to rise from 0.1 to 0.9 of its final value.


Riser - Main distribution cable segments that run between floors or sections of a building.


Riser cable - Cable that is UL Listed as having adequate fire resistance for installation without conduit in building riser applications such as elevator shafts. (Examples: CMR and OFNR rated.)


RIV - Radio influence voltage. The radio noise appearing on conductors of electric equipment or circuits.


RJ11 - A six-contact modular phone-type plug. It may have straight-through or crossover pinning depending on the application.


RJ45 - An eight contact modular AT&T phone-type plug that has 4-pair unshielded twisted-pair wire (eight wires twisted in pairs).


RMS - Root-mean square.


RML (restricted mode launch) - It simulates the launch conditions of a vertical cavity surface emitting laser (VCSEL) into a multimode fiber. Measuring RML bandwidth gives a better indicator of multimode fibers performance when used with a VCSEL.


RO - Ring out.


RO (read only) - A teleprinter receiver without a transmitter.


Rockwell hardness - A measure of hardness determined by resistance to indention by a small diamond or steel ball under pressure.


ROHS (Restriction of Hazardous Substances) - The RoHS is a European directive that restricts the use of certain hazardous substances in electrical and electronic equipment.


Roll - A loss of vertical sync which causes the picture to move up or down on the TV screen.


ROM (read-only memory) - Nonvolatile semiconductor storage device manufactured with predefined contents. Compare with EPROM, PROM, and RAM.


Romex - A type of nonmetallic sheathed (Type NM) cable. A trademark of the Southwire Company. Root mean square (rms) - The effective value of an alternating current or voltages.


Root-mean-square (rms) - In a periodic quantity, this is the square root of the average or mean of the squares of the quantity taken over a complete period.


Rope - lay conductor - See CONCENTRIC-LAY CONDUCTOR.


Rope concentric - A group of stranded conductors assembled in a concentric manner.


Rope strand - A conductor composed of a center group of twisted strands surrounded by layers of twisted strands.


Rope Unilay - A group of stranded conductors assembled in a Unilay manner.


Rope-lay conductor - See CONCENTRIC-LAY CONDUCTOR.


Rotating cable - A coil of cable whose inner end is attached to a member that rotates in relation to a member to which the outer end of the cable is fastened.


Round conductor flat cable - A cable made with parallel round conductors in the same plane.


Round wire shields - Shields constructed from bare, tinned or silver-plated copper wire that include braided, spiral and reverse spiral.


Router - A station that uses upper level protocols to control network communication between other stations. A dedicated router, such as a DECnet router, offloads the host computer of the routing function.


Route table - A database entered in the packet controller's memory by the system manager, containing addressing information on all nodes in the network. The packet controller refers to the router table when establishing virtual circuits between endpoints.


Routine tests - Tests made on each high-voltage cable or upon a representative number of devices, or parts, during production for the purposes of quality control.


RS-232 - An EIA recommended standard (RS); most common standard for connecting data processing devices, RS- 232 defines the electrical characteristics of the signals in the cable that connect DTE with DCE; it specifies a 25-pin connector (the DB-25 connector is almost universally used in RS-232 applications) and it is functionally identical to CCITT V.24/V.28.


RS-232-C - A technical specification published by the EIA that specifies the mechanical and electrical characteristics of the interface for connecting DTE and DCE. It defines interface circuit functions and their corresponding connector pin assignments. The standard applies to both asynchronous and synchronous serial, binary data transmission at speeds up to 20 kbps, in full- or half-duplex mode. RS- 232-C defines 20 specific functions. The physical connection between DTE and DCE is made through plug-in, 25-pin connectors. RS-232-C is functionally compatible with the CCIT Recommendation V.24.


RS-232-C serial I/O port - A standard connection interface for computer peripheral equipment.


RS-422 - A standard operating in conjunction with RS-449 that specifies electrical characteristics for balanced circuits. An EIA recommended standard for cable lengths that extended the RS-232 50-foot limit. Although introduced as a companion standard with RS-449, RS-422 is most frequently implemented on unused pins of DB-25 (RS-232) connectors. Electrically compatible with CCITT recommendation V.11.


RS-423 - A standard operating in conjunction with RS-449 that specifies electrical characteristics for unbalanced circuits. An EIA recommended standard for cable lengths that extended the RSD-232 50-foot limit. Although introduced as a companion standard with RS-422, RS-423 is not widely used. Electrically compatible with CCITT recommendation V.10.


RS-449 - Another EIA standard for DTE/DCE connection which specifies interface requirements
for expanded transmission speeds (up to 2 Mbps), longer cable lengths and 10 additional
functions. RS-449 applies to binary, serial, synchronous or asynchronous communications.
Half- and full-duplex modes are accommodated and transmission can be over 2- or 4-wire
facilities such as point-to-point multipoint lines. The physical connection between DTE and DCE is made through a 37-contact connector; a separate 9-connector is specified to service secondary channel interchange circuits, when used.


RS-485 - An EIA recommended standard which specifies electrical characteristics of generators and receivers for use in balanced digital multiport systems. It allows for multiple generators and receivers to be attached to a common interconnecting cable. Overall shielded twisted-pair cable is the primary transmission medium.


RTD - Resistance temperature sensing device. Converts temperature to an electrical signal.


RTS - Request-to-send. An RS-232 modem interface signal (sent from the DTE to the modem on pin 4) that indicates that the DTE has data to transmit.


RTSP - Real-time streaming protocol.


RTP (real-time transport protocol) - An IP protocol that supports real time transmission of voice and video. Real-time control protocol is a companion protocol that is used to maintain QoS.


RTU - Remote terminal unit.


Rubber, ethylene propylene (EPR) - A synthetic rubber insulation having excellent electrical properties.


Rubber insulation - A general term used to describe wire insulations made of Elastomer such as natural or synthetic rubbers, neoprene, CSPE, EPR, CPE and others.


RUS - Rural Utilities Service. A federal agency formerly known as the REA.

S

S - A UL cable type. Hard service flexible cord with thermoset insulation and jacket. Also see SO and SJ.


S band - A band of frequencies between 1,550 and 5,200 megahertz.


S meter - An instrument to measure signal strength.


S/n (signal-to-noise) ratio - Measure of noise levels of a video signal: the higher the number the better.


SAA - IBM's system application architecture. IBM's suite of protocols intended to foster interoperability and standard interfaces for applications in an IBM environment across all hardware architectures and operating environments.


SAE - Society of Automotive Engineers. Automotive standards body.


SAN (storage area network) - A self-contained data storage network separate from the regular data network.


Satellite equipment room - A room or wiring closet used as the central wiring hub.


Saturation (color) - The vividness of a color. It is directly related to the amplitude of the chrominance signal.


SBR - A copolymer of styrene and butadiene. Also GRS or Buna-S.


SC connector - A plastic connector with a precision ceramic or polymer ferrule designed for optical fiber subscriber channel (SC) networks. Manufactured under NIT license by various companies, it offers a non-optically disconnecting design with push-pull latching.


Scanning - The rapid movement of the election beam in a pickup device of a camera or in the CRT of a television receiver. It is formatted in a line-for-line manner across the photo sensitive surface that produces or reproduces the video picture. When referred to a video surveillance field, it is the panning or the horizontal camera motion.


Schering bridge - See BRIDGE.


Scrambling - A method of encoding data to make it look more random, resulting in lower spurious levels and easier timing recovery.


Screened twisted pair (ScTP) - 100-ohm twisted-pair cable with an overall foil shield and a drain wire typically used in Category 5 cable.


SCSI (small computer system interface) - Typically used for mass storage, i.e., hard disks.


SDI (serial data interface) - SDI cables are a type of coax used for HDTV. Comes in RG-59, RG-6 and bundled versions.


SDLC (synchronous data link control) - An IBM communications line protocol associated with SNA. SDLC provides for control of a single communications link or line, accommodates a number of network arrangements and operates in half- or full-duplex over private or switched facilities.


SDN - A small diameter multi-conductor control cable with neoprene jacket and nylon sheath over polyethylene insulation.


Secondary insulation - A nonconductive material that protects the conductor against abrasion and provides a second barrier.


Segment – (1) A length of coaxial cable made up of one or more cable sections connected together with barrel connectors or T-connectors. 2. In a LAN, a segment of coaxial trunk cable with a maximum of 1,640 feet (500 meters) of regular Ethernet and 600 feet (187 meters) of RG-58A/U Thinnet.


Segmental conductor - A stranded conductor consisting of three or more stranded conducting elements, each element having approximately the shape of the sector of a circle, assembled to give a substantially circular cross section.


Self-extinguishing - Characteristic of a material whose flame is extinguished after the igniting flame source is removed.


Semiconductor - In wire industry terminology, a material possessing electrical conduction properties that fall somewhere between 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.


Semiconducting jacket - A jacket having a sufficiently low-electrical resistance so its outer surface can be kept at substantially ground potential.


Semirigid cable - Generally refers to Type MI or Type ALS that can be bent or shaped into a required configuration from coils or reels.


Semirigid PVC - A hard semi flexible polyvinylchloride compound with low plasticizer content.


Semisolid - An insulation cross-section having a partially open space between the conductor and the insulation perimeter.


Sensitive conductor - A conductor terminated to a circuit that is adversely affected by spurious signals.


Sensitivity (pickup device) - The amount of current developed per unit of incident light. It can be measured in watts with the projection of an unfiltered incandescent source of light at 2,870 K degrees to the pickup device surface area. It can be then expressed in foot candles.


Separable insulated connector - An insulated device to facilitate cable connections and separations.


Separator - Pertaining to wire and cable, a layer of insulating material such as textile, paper, Mylar, etc., which is placed between a conductor and its dielectric, between a cable jacket and the components it covers, or between various components of a multiple-conductor cable. It can be used to improve stripping qualities and/ or flexibility, or can offer additional mechanical or electrical protection to the components it separates.


SE-R - Style R residential service entrance cable.


Serial interface - An interface that requires serial transmission, or the transfer of information in which the bits composing a character are sent sequentially. Implies only a single transmission channel.


Serial transmission - A technique in which each bit of information is sent sequentially on a single channel, rather than simultaneously as in parallel transmission. Serial transmission is the normal mode for data communications. Parallel transmission is often used between computers and local peripheral devices.


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


Serve - A filament or group of filaments such as fibers or wires, wound around a central core.


Served wire armor - Spiral wrap of soft galvanized steel wires wrapped around a cable to afford mechanical protection and increase the cable-pulling tension characteristic.


Server - A processor that provides a specific service to the network. Examples of servers are as follows: routing servers connect nodes and networks of like architectures; gateway servers connect nodes and networks of different architectures by performing protocol conversions; and terminal servers, printer servers and file servers provide an interface between compatible peripheral devices on a LAN.


Serving - A wrapping applied over the core of a cable or over a wire.


SE - A UL cable type. Service entrance cable, 600 volts.


SEW, SEWF - A CSA cable type. Silicone rubber-insulated equipment wire.


S/FTP - Foil and braided overall shield applied over individually foil shielded twisted pairs. Also referred to as PIMF cable.


SF - A CSA cable type. Silicone rubber insulated fixture wire, solid or seven-strand conductor, 200°C.


SFF - A CSA cable type. Same as SF, except flexible stranding 150°C.


SG - A CSA cable type. Same as SW except with ground wires.


SGO - A CSA cable type. Same as SWO except with ground wires.


Shared access - In LAN technology, an access method that allows many stations to use the same (shared) transmission medium. Contended access and explicit access are two kinds of shared access methods. Contrast with DISCRETE ACCESS.

SHD - Portable mine power cable, three or four individually shielded conductors, with grounding conductors, 5 kV through 25 kV.


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


Shield - A sheet, screen or braid of metal, usually copper, aluminum or other conducting material placed around or between electric circuits, cables or their components to contain any unwanted radiation or to keep out any unwanted interferences.


Shield coverage - See SHIELD PERCENTAGE.


Shield effectiveness - The relative ability of a shield to screen out undesirable radiation. Frequently confused with the term shield percentage, which it is not.


Shield percentage - The physical area of a circuit or cable actually covered by shielding material, expressed in percent.


Shielded insulated splice - An insulated splice in which a conducting material is employed over the full length of the insulation for electric stress control.


Shielded line - A transmission line whose elements confine radio waves to an essentially finite space inside a tubular conducting surface called the sheath, thus preventing the line from radiating radio waves.


Shielding, power cable - A conducting layer applied to increase safety, control dielectric stresses and prevent partial discharges.


Short - A low resistance path that results in excessive current flow and often in damage.


Short-haul modem - See LINE DRIVER.


Shovel cable - Normally an SHD-GC type that supplies high-voltage (2 kV to 25 kV) power to mobile equipment.


Shrinking ratio - The ratio between the expanded diameter and recovered diameter of shrinkable products.


Shrink Temperature - The temperature that effects complete recovery of a heat shrinkable product from the expanded state.


Shrink tubing - Tubing that has been extruded, cross-linked and mechanically expanded, which when reheated or released will return to its original diameter.


Shunt - A very low-resistance component used to divert a proportion of the current.


Shunt wire - A conductor joining two parts of an electric circuit to divert part of the current.


SI - An international system of standardized units of measurement.


SIA (Security Industry Association) - Professional organization involved in CCTV, access control, computer security, and fire and burglar alarm systems.


SIC (SPECIFIC INDUCTIVE CAPACITANCE) - See DIELECTRIC CONSTANT.


Signal - Any visible or audio indication which can convey information. Also, the information conveyed through a communications system.


Signal cable - A cable designed to carry current of usually less than one ampere per conductor.


Signal-to-noise ratio (S/N or SNR) - A ratio of the amplitude in a desired signal to the amplitude of the noise, usually expressed in decibels (dB).


Silicon avalanche zener diodes - A solid-state junction device. These devices are very fast acting but have low energy-handling capability. Switching speed is in picoseconds. They work by shunting the surge of spike impulse around the protected circuits.


Silicone - 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.


Simplex (multiplexer) - A multiplexer that allows the user to look at multiscreen images or perform time multiplex recording. It cannot record multiplexer pictures while showing multiscreen pictures.


Simplex transmission - Transmission is only one direction.


Single-cable - A one-cable system in broadband LANs in which a portion of the bandwidth is allocated for send signals and a portion for receive signals with a guard band in between to provide isolation from interference.


Single-mode - Optical fiber in which only one mode of light can propagate.


Single-segment LAN - A LAN composed of only one coaxial cable segment.


Sintering - Fusion of an extruded paste or a spirally applied tape wrap insulation or jacket by the use of high heat to a homogenous continuum. Usually employed for fluorocarbon, nonextrudable materials.


SIO - Serial input/output.


SIP - Session initiation protocol.


SIS - Switchboard wiring made with cross-linked polyethylene insulation.


Sixty-six (66) type wiring - A type of distribution system cross-connect and termination hardware developed by AT&T in the mid-1950s. The 66 is part of a Western Electric product code assigned sequentially to new products.


SJ - A UL or CSA cable type. Junior hard service, rubber-insulated pendant or portable cord. Same construction as type S, but 300 V.


SJO - Same as SJ, but with oil-resistant jacket.


SJOO - Same as SJO but with oil-resistant insulation as well as an oil-resistant jacket.


SJT - A UL or CSA cable type. Junior hard service thermoplastic or rubber insulated conductors with overall thermoplastic jacket. 300 V.


SJTO - Same as SJT but oil-resistant thermoplastic outer jacket.


SJTOO - Same as SJTO but with oil-resistant insulation.


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


Slope - The difference between attenuation at the highest frequency and at the lowest frequency in a cable system. Also called spectrum tilt.


Slope compensation - The action of an equalizer or an automatic slope-compensated amplifier.


SMDS (switched multimegabit data service) - A public, connectionless, packet-switched data service that provides LAN-like performance and features over a metropolitan or wide area.


SMF - Single-mode fiber.


SMS (short message service) - Text service used with wireless networks.


SNA (systems network architecture) - The network architecture developed by IBM.


SN238 - The system 85 interface; a 4-port circuit pack.


SNA/SDLC - See SNA and SDLC.


SNM - Shielded nonmetallic sheathed cable.


SNMP (simple network management protocol software) - A computer program or set of computer programs held in some kind of storage medium and loaded into read/write memory (RAM) for execution. Compare with firmware and hardware.


SO - A UL or CSA cable type. Hard service cord, same construction as type S except oil-resistant thermoset jacket, 600 V.


SOFT WIRE - Wire that has been drawn or rolled to final size and then heated (annealed) to remove the effects of cold working.


SOHO - Small office/home office.


SOLEF - Solvay's trademark for its PVDF polymer.


Solid conductor - A conductor consisting of one wire.


SONET (Synchronous Optical NETwork) - An emerging broadband fiber network formed by a family of network elements that conform to the SONET interface requirements. SONET is a transport network of synchronously multiplexed tributary signals. The basic electrical signal of SONET runs at a rate of 51,840 Mbps. SONET grows in multiples of the basic signal into the multigigabit range.


SOO - Same as SO but with oil-resistant insulation.


SOOW - A UL or CSA cable type. Portable cord and control cable. 600 V. Same as SOO but UL Listed or CSA Certified for outdoor use.


Source coupling loss - Loss of light intensity as the light from a source passes into an optical fiber.


SP-1 - A UL cable type. All thermoset, parallel-jacketed, two-conductor light duty cord for pendant or portable use in damp locations, 300 V.


SP-2 - Same as SP-1, but heavier construction, with or without a third conductor for grounding purposes, 300 V.


SP-3 - Same as SP-2, but heavier construction for refrigerators or room air conditioners, 300 V.


Spacer cable - A type of overhead power distribution cable. Spacing is accomplished by ceramic or plastic hangers suspended from a support messenger.


SPAN - In flat conductors, distance between the reference edge of the first and the last conductor. In


Span line - The T1 line facility between two locations.


SPC - Statistical process control.


Specific inductive capacity (SIC) - Dielectric constant of an insulating material.


SPID (service ptttt- A unique identifier that is programmed into ISDN devices in order for them to operate properly.


Spiral shield - A metallic shield of fine stranded wires applied spirally rather than braided.


Spiral stripe - A color coding stripe applied helically to the surface of an insulated wire or cable.


Spiral wrap - The helical wrap of a tape or thread over a core.


SPL (sound pressure level) - The acoustic pressure reference for the dB. The minimum threshold of undamaged human hearing is 0 dB SPL. The threshold of pain of undamaged human hearing is 120 dB SPL.


Splice - The physical connection of two or more conductors to provide electrical continuity.


Splitter - A passive device used in a cable system to divide the power of a single input into two or more outputs of lesser power. Can also be used as a combiner when two or more inputs are combined into a single output.


Spot filter - A small insert used in a lens to increase the f-stop range of the lens.


SPT - A UL type of thermoplastic-insulated, two- or three-conductor parallel cord. Frequently called "zip cord" or "lamp cord."


Squirrel cage motor - An induction motor having the primary winding (usually the stator) connected to the power and a current is induced in the secondary cage winding (usually the rotor).


SR - Silicone rubber cable 600 V, 125°C.


SRG - A cable with ozone-resistant silicone rubber insulation with an overall jacket of braided glass yarn impregnated with flame-, heat- and moisture-resistant finish. 150/200°C 600 V appliance and motor lead wire.


SRGK - A cable with ozone-resistant silicone rubber insulation with braided glass yarn conductor jacket. Cable core of insulated conductors shielded or unshielded and an overall jacket of braided K-fiber impregnated with flame-, heat- and moisture resistant finish. 150/200°C 600 V multiconductor cable.


SRK - A cable with ozone-resistant silicone rubber insulation with an overall jacket of braided K-fiber impregnated with flame-, heat- and moisture-resistant finish. 200°C 600 V fixture wire and power cable.


SRL (structural return loss) - A measure of the variation of impedance down a length of cable.Impedance variations cause a return reflection of a portion of a signal's energy back to the transmitter, which looks like noise.


SSH (secure shell) - A type of secure network access software used on a gateway computer. Provides a safe way to access a private network over the Internet.


SSID (service set identifier) - An identifier used in wireless LAN (WLAN) applications.


SSL (secure socket layer) - A cryptographic protocol for securing data on the Internet.


ST - A UL cable type. Hard service cord, jacketed, same as type S except thermoplastic construction. 600 V, 60°C to 105°C.


ST1 - Smoke Test #1. An optional rating for UL Listed cable types that also pass the Limited Smoke requirements contained in UL Standards. A cable that meets the requirement can be marked "ST1."


Stability factor - The difference between the percentage power factor at 80 volts/mil and at 40 volts/mil measured on wire immersed in water at 75°C for a specified time.


Standard - A set of rules or protocols that describe how a device should be manufactured, so it will maintain interoperability (compatibility) with others of the same type from different manufacturers.


Standard Ethernet - An IEEE 802.3 compliant Ethernet network composed of standard Ethernet cable as opposed to thin Ethernet cable.


Standby UPS - A UPS system that normally connects your equipment to the normal AC power line with the batteries and inverter in standby mode. When the power line is weak or fails, it transfers the load to the batteries and inverter without any load malfunction and without any user action. When the power line returns to normal, the load is automatically retransferred back to the AC power line.


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 of a standing wave stated in current or voltage amplitudes.


Star - A network topology consisting of one central node with point-to-point links to several other nodes. Control of the network is usually located in the central node or switch, with all routing of network message traffic performed by the central node.


Start bit - In asynchronous transmission, the first bit used to indicate the beginning of a character, normally, a space condition which serves to prepare the receiving equipment for the reception and registration of the character.


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


Station - 1. A network node. 2. The customer location or customer equipment.


Station adapter - An active device used to connect PC/ workstations that have transceiver connectors to thin-wire Ethernet cable.


Station cable - The part of the distribution system that begins at a cross-connect in either an equipment room or serving closet and terminates at the user room.


Station protector - A gas discharge, carbon block or other device that short circuits harmful voltages to ground in the event of lightning strikes on the phone line.


ST connector - A plastic or metal connector with a precision ceramic, polymer, or stainless steel straight tip (ST) ferrule and bayonet-style latching.


Stay cord - A component of a cable, usually a high-tensile textile, used to anchor the cable ends at their points of termination and to keep any pull on the cable from being transferred to the electrical connections.


Step index fiber - A multimode optical fiber consisting of a core of uniform refractive index, surrounded by cladding of slightly lower refractive index.


Stiffness - As applied to copper, the property of a conductor that causes it to resist permanent deformation by bending.


STO - A North American flexible cord type. Same as ST but with an oil-resistant thermoplastic outer jacket, 600 V, 60°C.


STOO - Same as STO but with oil-resistant insulation.


STOOW - Same as STOO but suitable for use in wet locations.


Stop bit - In asynchronous transmission, the last bit used to indicate the end of a character; normally a mark condition which serves to return the line to its idle or rest state.


Stop bits - One or two bits in an asynchronous communication to indicate the end of the transmission. In ISN, one of the endpoint options which can be specified for an AIM port. The option can be set to either one or two stop bits.


Stop joint - A splice that is designed to prevent any transfer of dielectric fluid between the cables being joined.


STP (spanning tree protocol) - A fault tolerance protocol. Allows multiple paths to be created between a pair of LAN segments but keeps only a primary path open. When a primary path fails an alternate path will be activated to maintain the connection.


Straight joint - A cable splice used for connecting two lengths of cable, each of which consists of one or more conductors.


Strain gauge - A device for determining the amount of strain (change in dimension) when a stress is applied.


Strain hardening - An increase in hardness and strength caused by plastic deformation at temperatures lower than the recrystallization range.


Strand - One of the wires of any stranded conductor.


Stranded conductor - A conductor composed of a group of wires, usually twisted, or of any combination of such groups of wires.


Strand lay - The distance of advance of one strand of a spirally stranded conductor, in one turn, measured longitudinally. Also referred to as lay length.


Stress-relief cable - Cable used to relieve stresses in the process of welding pipe joints by inducing heat in pipe sections to be welded, flexible copper strand.


Stress-relief cone (termination) - A device used to relieve the electrical stress at a shielded cable termination; generally used above 2,400 volts.


Strip - To remove insulation from a wire or cable.


Structural return loss- Backward reflected energies from uneven parts of the cable structure.


Subchannel - A frequency subdivision created from the capacity of one physical channel by broadband LAN technology. Bands of frequencies of the same or different sizes are assigned to transmission of voice, data, or video signals. Actual transmission paths are created when each assigned band is divided, using FDM, into a number of subchannels.


Subrate - A customer channel transmission rate less than 64 kbps. Examples: 2.4, 4.8, 9.6, 19.2 kbps.


Subscriber - A customer.


Substrate - Insulating material layer on a printed wiring board.


Suggested working voltage - AC voltage that can be applied between adjacent conductors.


Superconductors - Materials whose resistance and magnetic permeability are virtually zero at very low temperatures.


Suppressor - A device used to reduce or eliminate unwanted voltages in electric or electronic circuits. For example, a resistance conductor in, or a resistor in series with, a sparkplug cable, to suppress interference that would otherwise affect radio reception in and near the vehicle.


Surface resistivity - The resistance of a material between two opposite sides of a unit square of its surface. It is usually expressed in ohms.


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


Surge protector - A device that plugs between the phone system and the commercial AC power outlet. It is designed to protect the phone system from high-voltage spikes (surges) that might damage the phone system. When a surge occurs on the power line, the surge protector sends the overload to ground.


SV - A North American cable type. Vacuum cleaner cord, two or three conductor, rubber insulated. Overall rubber jacket. For light duty in damp locations, 300 V 60°C.


SVO - A North American cable type. Same as SV except oil-resistant thermoset jacket, 300 V 60°C or 90°C.


SVT - A North American cable type. Same as SV except thermoplastic jacket. 300 V, 60°C or 90°C.


SVTO - A North American cable type. Same as SVT, except with oil-resistant thermoplastic jacket, 60°C.


SW - A CSA cable type. Rubber jacketed power supply cable (8 AWG to 2 AWG) 600 V.


SWR - Standing wave ratio. The ratio of incoming to reflected energy in a cable system. See also VSWR.


Sweep test - A test to check attenuation at a range of frequencies.


Sync - Synchronous.Electronic pulses that are inserted in the video signal for the purpose of assembling the picture information in the correct position.


Synchronization - Maintaining a constant phase relationship between AC signals.


Synchronous transmission - Transmission in which there is a constant time between successive bits, characters or events. The timing is achieved by sharing of clocking.


SYS - System.


System 75 - An AT&T digital PBX that provides voice and data transport for small- to medium-sized offices.


System 85 - An AT&T digital PBX that provides voice and data transport for medium- to large-sized offices.

T

T - Thermoplastic vinyl, building wire, 60°C.


T Connector - A cable adapter that attaches a PC with a thinnet network interface module to the network.


T1 - The basic 24-channel 1.544 Mbps pulse code modulation system used in the United States (2.048 Mbps elsewhere). 1.544 Mbps is the old Bell System standard and 2.048 is the CCITT standard.


T1 carrier - The AT&T digital transmission system that sends data at 1.544 Mbps. With it you can simultaneously transmit 24 voice conversations, each encoded at 64,000 bits per second. More voice signals can be transmitted if you encode each conversation with fewer bits.


T3 - A digital transmission link with the capacity of 45 Mbps. Connection to the Telco is via a 4-wire or 2-wire hook-up, depending on the LEC. The equivalent of twenty-eight T1 lines or 672 56 kbps lines.


Take-up - The process of accumulating wire or cable onto a reel, bobbin or some other type of pack. Also, the device for pulling wire or cable through a piece of equipment or machine.


Tandem connection - A back-to-back connection of channel units to provide a communication path or link.


Tank test - A dielectric strength test in which the test sample is submerged in water and voltage is applied between the conductor and the water acting as ground.


Tank test - A dielectric strength test in which the test sample is submerged in water and voltage is applied between the conductor and the water acting as ground.


Tap - 1. Baseband: The component of a connector that attaches a transceiver to a cable. 2. Broadband (also called a directional tap or multi tap): A passive device used to remove a portion of the signal power from the distribution line and deliver it onto the drop line.


Taped insulation - Insulation of helically wound tapes applied over a conductor or over an assembled group of insulated conductors.


Tape wrap - A spirally applied tape over an insulated or un-insulated wire.


Taped splice - A joint with hand-applied tape insulation.


TBB - Telecommunications bonding backbone.


TBBIBC - Telecommunications bonding backbone interconnecting bonding conductor.


TC - Telecommunications closet.


TCLP - Toxicity characteristic leaching procedure. A test created by the EPA to determine whether an item can be safely discarded in an ordinary (nonhazardous) landfill.


TCP/IP (Transmission Control Protocol/Internet Protocol) - A protocol specification that conforms to the latest DoD ARPANET standard. The TCP/IP module corresponds to layers three and four of the ISO protocol model.


TDM (time division multiplexing) - A method utilizing channel capacity efficiently in which each node is allotted a small time interval, in turns, during which it may transmit a message or a portion of a message (for instance, a data packet). Nodes are given unique time slots during which they have exclusive command of the channel. The messages of many nodes are interleaved for transmission and then de-multiplexed into their proper order at the receiving end.


TDMA (time-division multiple access) - A high-speed, burst mode of operation that can be used to interconnect LANs; first used as a multiplexing technique on shared communications.


TDR - Time domain reflectometer.


Tear strength - The force required to initiate or continue a tear in a material under specified conditions.


Tearing - A picture condition in which horizontal lines are displaced in an irregular manner.


Teflon - 1.Tetrafluoroethylene 2.Trademark of the DuPont Co. for FEP, PTFE and PFA polymers.


Telco - Short for telephone company.


Telco 25- and 50-pair cable assembly - The Telco 25- and 50-pair are terminated with Amphenol157 Series or AMP Champ series connectors or other manufacturers. They are used to interconnect PABXs, controllers, modems, hubs, etc.


Telco modular cable assemblies - The twisted-pair telephone cable allows the interface of voice, video and data operation.


Telecommunications - Any transmission emission, or reception of signs, signals, writings, images and sounds, that is information of any nature by cable, radio, optical or other electromagnetic systems.


Telecommunications closet - The closet where riser cable is terminated and cross-connected to the horizontal distribution cable or other riser cable. The riser closet houses cross-connect facilities, and may contain electronics such as hubs and auxiliary power supplies for terminal equipment located at the user work location.


Telemetry - Transmission of coded analog data, often real-time parameters, from a remote site.


Tempatrure rating- The maximum temperature at which an insulating material may be used in continuous operation without loss of its basic properties.


Tensile strength - The maximum load per unit of original cross-sectional area that a conductor attains when tested in tension to rupture.


Terminal - Any device capable of sending or receiving data over a data communications channel.


Terminal alarms - Alarm indications at the transmission terminals such as a D4 channel bank.


Terminal block - A protected or unprotected unit of wiring blocks and troughs that serves as a transition point between cable conductors.


Terminal server - 1. A device which controls communication between terminals and hosts, thus off-loading hosts of this function. 2. In LAN technology, a device that allows one or more terminals or other devices to connect to an Ethernet LAN.


Terminals - Metal wire termination devices designed to handle one or more conductors, and to be attached to a board, bus or block with mechanical fasteners.


Termination - A generic term meaning the point at the end of a cable run where the cable's conductors are attached to a termination connection such as a connector, plug, block or patch panel. Also a noninductive resistor that has the same resistance as the characteristic of the cable being used.


Termination point - The ending point of a circuit.


Terminator - A resistive device used to terminate the end of a cable or an unused tap into its characteristic impedance. The terminator prevents interference-causing signal reflections.


Test lead - A flexible, insulated lead wire used for making tests, connecting instruments to a circuit temporarily, or for making temporary electrical connections.


Tew - Canadian Standards Association type appliance wires. Solid or stranded single conductor, plastic-insulated, 105°C, 600 V TFE.


Textile braid - Any braid made from threads of cotton, silk or synthetic fibers.


TF - A UL cable type. Fixture wire, thermoplastic-covered solid or seven strands, 60°C.


TFE - One of three types of Teflon. Also known as PTFE (polytetrafluoroethylene).


TFF - Same as TF but flexible stranding, 60°C.


TFFN - Same as TFF but with nylon outer jacket.


TFN - Same as TF but with nylon outer jacket.


TG - Flexible nickel or nickel-clad copper conductor, Teflon tape, glass braid, 200°C.


TGB - Telecommunications grounding busbar.


TGGT - PTFE Teflon tape insulation with an insulation covering of wrapped glass yarn and an overall sheath of braided glass yarn impregnated with a moisture, heat, flame and fraying resistant compound. 600 V, 250°C appliance wire.


TGS - Solid or flexible copper, nickel-clad iron or copper, or nickel conductor. Teflon tape, silicone glass braid, 600 V 250°C.


Thermal aging - Exposure to a thermal condition or programmed series of conditions for pre-described periods of time.


Thermal shock - Taking an electronic device from an elevated ambient temperature where it has stabilized and immersing it in a severely cold environment, so cooling of the device is extremely rapid.


Thermocouple - A device consisting of two dissimilar metals in physical contact, which when heated will develop an EMF output.


Thermocouple element - A thermocouple designed to be used as part of an assembly, but without associated parts such as terminal block, connecting head or protecting tube.


Thermocouple extension cable - A cable comprised of one or more twisted thermocouple extension wires under a common sheath.


Thermocouple extension wire - A pair of wires of dissimilar alloys having EMF temperature characteristics complementing the thermocouple with which it is intended to be used, such that when properly connected allows the EMF to be accurately transmitted to the reference junction.


Thermocouple lead wire - An insulated pair of wires used from the thermocouple to a junction box.


Thermoplastic - A plastic material that softens and flows when heated and becomes firm when cooled. This process can be repeated.


Thermoset - A plastic material that is cross linked by a heating process known as curing. Once cured, thermoset cannot be reshaped.


THHN (thermoplastic high-heat resistant nylon coated) - THHN conductors are primarily used for power and control circuits in commercial and industrial applications. THHN meets or exceeds UL Standard 83; conductors rated for 600 V, 90°C operation in dry locations. Product is oil, gasoline and abrasion resistant. It is the common electrical wire that electricians pull in conduit.


Thick Ethernet (Thicknet) - In LAN technology, an Ethernet LAN or IEEE 802.3 LAN that uses a bus topology. Also known as 10BASE5.


Thin Ethernet - In LAN technology, an Ethernet LAN or IEEE 802.3 LAN that uses smaller-than-normal diameter coax often used to link IBM personal computers together. Operates at same frequency as Ethernet but at smaller distances. Also known informally as cheapernet.


Thinwire - A variant of 10 Mbps Ethernet that uses thin coaxial cable (RG-58 or similar, as opposed to the thicker RG-8 cable used in 10BASE5 networks) terminated with BNC connectors.


Three-phase current - Current delivered through three wires, with each wire serving as a return for the other two.


Three-phase three-wire system - An alternating current supply system comprising three conductors over which three-phase power is sent.


Three-quarter-hard wire - As applied to aluminum, wire that has been processed to produce a strength approximately midway between that of half-hard wire and that of hard-drawn wire.


Three-wire system - A DC or single-phase AC system comprising three conductors, one of which is maintained at a potential midway between the potential of the other two.


Throughput - The total useful information processed or communicated during a specified time period. Expressed in bits per second or packets per second.


THW - A UL cable type. Thermoplastic vinyl-insulated building wire. Flame-retardant, moisture and heat resistant. 75°C rated in dry and wet locations.


THW-2 - A UL cable type. Thermoplastic vinyl-insulated building wire. Flameretardant, moisture and heat resistant. 90°C rated in dry and wet locations.


THWN (thermoplastic heat- and water-resistant nylon coated) - A UL cable type. Same as THW but with nylon jacket overall. THWN conductors are primarily used for power and control circuits in commercial and industrial applications. THWN meets or exceeds UL Standard 83; conductors rated for 600 V; 90°C operation in dry locations and 75°C in wet locations. Product is oil, gasoline and abrasion resistant.


THWN-2 - A UL cable type. Same as THW but with nylon jacket overall. Rated 90°C in wet and dry locations.


TIA - Telecommunications Industry Association.


TIA/EIA-568 Commercial Building Telecommunications Cabling Standard - The U.S. standard that specifies:

    Minimum requirements for telecommunications cabling within an office environment
    Recommended topology and distances
    Media by parameters that determine performance
    Connectors and pin assignments to ensure interconnectivity
    The useful life of telecommunications cabling systems to be in excess of ten years


Timebase corrector (TBC) - An electronic circuit that aligns unsynchronized video signals before signal processing. Used in multiplexers and quad splatters.


Timing pulses - Pulses used for synchronizing the transceiver circuits of a transmission facility. They can be generated from a local, loop or external source.


Tinned wire - See COATED WIRE.


Tin overcoat (TOC) - Tinned copper wire, stranded, then coated with tin.


Tinsel wire - A low-voltage stranded wire, with each strand a very thin conductor ribbon spirally wrapped around a textile yarn.


Tip - One of the two wires in a telephone circuit. The tip wire usually has a positive battery potential relative to the ring wire.


TKGT - PTFE Teflon tape insulation with an insulating covering of felted K-fiber yarn and an overall sheath of braided glass yarn impregnated with a moisture-, heat-, flame- and fraying-resistant compound. 250°C 600 V apparatus and motor lead wire.


TL-9000 - A quality system for the telecommunications industry based on ISO 9000.


TMGB - Telecommunications main grounding busbar.


TNC - A threaded connector for miniature coax; TNC is said to be an abbreviation for threaded-NeillConcelman. Contrast with BNC.


Token bus - A LAN access mechanism and topology in which all stations actively attached to the bus listen for a broadcast token or supervisory frame; stations wishing to transmit must receive the token before doing so. However, the next logical station to receive the token is not necessarily the next physical station on the bus. Bus access is controlled by pre-assigned priority algorithms.


Token passing - A mechanism whereby each device receives and passes the right to use the channel. Tokens are special bit patterns or packets usually several bits in length that circulate from node to node when there is no message traffic. Possession of the token gives a node exclusive access to the network for transmitting its message.


Token ring - The token access procedure used on a network with sequential or ring topology; passes tokens from adapter to adapter.


TOP (technical office protocol) - An OSI profile designed for the technical and office LAN environment.


Topcoated - Bare (untinned) copper wire, stranded then coated with pure tin.


Topology - 1. Physical topology; the configuration of network nodes and links. Description of the physical geometric arrangement of the links and nodes that make up a network, as determined by their physical connections. 2. Logical topology; description of the possible logical connections between network nodes, indicating which pairs of nodes are able to communicate, whether or not they have a direct physical connection. Examples of network topologies are as follows:

    Bus
    Ring
    Star
    Tree


TP-MAU (twisted-pair medium access unit) - DSI's MAU that provides conversion from an AUI connector to a 10BASE-T RJ45 connector.


TP-PMD - Twisted-pair physical layer medium dependent.


TPE - Thermoplastic elastomer.


Tracer - A means of identifying an individual conductor (e.g., for polarity, etc.).


Tracking - A zoom lens's ability to remain in focus during the entire zoom range from wide angle to telephoto position.


Transceiver - A device required in baseband networks that takes the digital signal from a computer or terminal and imposes it on the baseband medium.


Transceiver cable - Cable connecting the transceiver to the network interface controller allowing nodes to be placed away from the baseband medium.


Transceiver drop cable - A cable used to attach a drop device to a standard Ethernet segment.


Transceiver tap - The transceiver mounting mechanism that allows transceivers to be installed on a network without interrupting network operation.


Transducer - Any device that senses one form of energy and converts it to another, as sound, force, temperature or humidity to electrical energy, or vice versa.


Transfer impedance - The ratio of the source voltage of the wires inside the cable to the shield current of a cable or connectorized cable assembly.


Transfer impedance test - A laboratory test that measures the effectiveness of a cable shield to keep EMI in (or out) of the cable. Usually conducted per NEMA WC61. Sometimes also referred to as a "surface transfer impedance" test.


Transition splice - A cable splice that connects two different types of cable.


Translation frequency - The difference between the receive and transmit frequencies.


Transition splice - A cable splice that connects two different types of cable.


Translator - An active device located at the headend that received inbound RF signals from devices connected to the network, converts them to signals at outbound frequencies and sends them back to the network in the outbound direction.


Transmission - The dispatching of a signal, message, or other form of intelligence by wire, radio, telegraphy, telephony, facsimile, or other means.


Transmission cable - Two or more transmission lines. See TRANSMISSION LINE.


Transmission line - The conductors used to carry electrical energy from one location to another.


Transmission loss - The decrease or loss in power during transmission of energy from one point to another. Usually expressed in decibels.


Transmission media - The various types of wire and optical fiber cable used for transmitting voice, data or video signals.


Transmission medium - A physical carrier of electrical energy or electromagnetic radiation.


Transmitter - In a telephone it is the device in the handset that converts speech into electrical impulses for transmission.


Transposition - Interchanging the relative positions of wires to neutralize the effects of induction to or from other circuits or to minimize interference pickup by the lead-in during reception.


Tray - A cable tray system is an assembly of units or sections and ancillary fittings, made of noncombustible materials used to support cables. Cable tray systems include ladders, troughs, channels, solid bottom trays and similar structures.


Tray cable - A factory-assembled multi-conductor or multi-pair control cable approved under the National Electrical Code for installation in trays.


Treeing - Microscopic tree-like channels in medium-voltage cable insulation that can lead to cable failure.


Triaxial - A three-conductor cable with one conductor in the center, a second circular conductor concentric with and insulated from the first, and a third circular conductor insulated from and concentric with the second, and an impervious sheath overall.


Triboelectric noise - Noise generated in a shielded cable due to variations in capacitance between shielding and conductor as the cable is flexed.


Trolley wire - A round or shaped solid, bare, hard conductor ordinarily used to supply current to motors through traveling current collectors.


True concentric - A cable conductor in which each successive strand layer has a reversed direction of lay from the preceding layer.


Trunk - 1. A carrier facility (e.g., a telephone line) between two switches. 2. A telephone communications path, or channel, between two points, one of them usually being a telephone company central office or switching center. 3. The main coaxial cable which connects the headend to major segments of cable system distribution networks. Typically, a trunk cable will be used to interconnect building networks in a multi-building network.


Trunk, analog - A trunk cable that carries voice and data traffic as analog signals.


Trunk cable - A main cable used for distribution of signals over long distances throughout a cable system.


Trunk, digital - A trunk that carries voice and data traffic as digital signals.


Trunk processing - To disconnect channel units from service, so customer access is denied. This is done automatically by D4 equipment when a facility failure occurs.


TR-XLP - Tree retardant cross-linked polyethylene.


TSB (Telecommunications System Bulletin) - Additional information about an existing TIA/EIA spec. These are sometimes incorporated into later versions of the spec. A TSB is not a standard, but rather contains technical material that may be valuable to industry and users.


Tubing - A tube of extruded unsupported plastic material.


Turnkey system - Any system that is completely assembled and tested and that will be completely operational by turning it on.


TV camera cable – Multi-conductor (often composite) to carry power for camera, lights, maneuvering motors, intercom signals to operators, coaxials, etc. Usually heavy-duty jacketed.


TW - A UL wire type. Thermoplastic vinyl-jacketed building wire, moisture resistant and rated 60°C.


Twinaxial cable - A shielded cable with two conductors that are insulated from one another and are within (and insulated from) a conductor of larger size.


Twinaxial cable assemblies (IBM) - Utilizes two coaxial systems into one connector. It is used by IBM to interface mainframes, controllers, PCs and all other compatible material.


Twin coaxial - A coaxial cable configuration containing two separate, complete coaxial cables laid parallel or twisted around each other in one unit.


Twin-lead - A transmission line having two parallel conductors separated by insulating material. Line impedance is determined by the diameter and spacing of the conductors and the insulating material and is usually 300 ohms for television receiving antennas. Also called balanced transmission line and twin-line.


Twinner - A device for twisting together two conductors.


Twinnning - Synonymous with pairing.


Twisted pair - 1. Multiple-conductor cable whose component cables are paired together twisted and enclosed within a single jacket. 2. Two insulated copper wires twisted together. The twists, or lays, are varied in length to reduce the potential for signal interference between pairs. In cables greater than 25 pairs, the twisted pairs are grouped and bound together in a common sheath. Twisted-pair cable is the most common type of transmission media.

U

U-bend test - A cable test in which the insulation is tested for resistance to corona and ozone.


UART (universal asynchronous receiver-transmitter) - A device that converts outgoing parallel data from your computer to serial transmission and converts incoming serial data to parallel for reception.


UDP - Universal datagram protocol.


UF - A UL Underground Feeder cable type. Thermoplastic underground feeder or branch circuit cable.


UHF - Ultrahigh frequency, the band extending from 300 to 3,000 MHz as designated by the Federal Communications Commission.


UL - Underwriters Laboratories, Inc. A U.S. independent testing laboratory that also publishes standards for most products in the NEC.


UL Approved - Tested and approved by the Underwriters Laboratories, which was established by the National Board of Fire Underwriters to test equipment that may affect insurance risks of fire and safety. Most phone systems are tested and approved. Most of the testing focuses on the power supply feeding the phone system. The power supply plugs into the AC wall outlet, takes 120 volt AC and converts it to low-voltage DC power that the phone system typically runs on. If the power supply tests OK, then that is usually sufficient UL testing. It is the power supply - and what happens to the commercial AC power that feeds into the power supply - that determines the potential fire hazard a phone system poses. In addition to the UL approval, the other major fire concern is the use of proper wire in new building construction, with special emphasis on Teflon-covered cable in plenum ceilings.


UL Certified (Verified or Classified) - A product that has been tested to a manufacturer or industry standard (i.e., electrical performance).


UL listed - A product that has been tested and found to comply with applicable standards. Listing also involves regular follow-up to ensure continued compliance.


UL Recognized - A product that contains components that are UL Listed.


UL Style - A subset of UL Type AWM (appliance wiring material) consisting of thousands of different styles. Many UL styles are single-conductor hook-up wire. A unique four or five digit number, e.g., UL 1015, identifies each style. Styles identify an additional subset of features from the referenced standards in order to allow customers to quickly identify the type of wire needed.


Ultrasonic cleaning - Immersion cleaning aided by ultrasonic waves that cause microagitation.


Ultrasonic detector - A device that detects ultrasonic noise such as that produced by corona or leaking gas.


Ultraviolet - Radiant energy within the wavelength range 10 to 380 nanometers. It is invisible and can be filtered out by glass.


Unbalanced line - A transmission line in which voltages on the two conductors are unequal with respect to ground (e.g., coaxial cable).


Unbalanced-to-ground - Describing a two-wire circuit, where the impedance-to-ground on one wire is measurably different from that on the other, compare with BALANCED LINE.


Unconnectorized - A term used to describe bare-ended cable, i.e., cable without factory-attached connectors. See also CONNECTORIZED.


Unidirectional conductor - See CONCENTRIC-LAY CONDUCTOR.


Unidirectional stranding - A term denoting that in a stranded conductor all layers have the same direction of lay.


Unilay - More than one layer of helically-laid wires with the direction of lay and length of lay the same for all layers. See CONCENTRIC-LAY CONDUCTOR.


UPS (uninterruptible power system) - An online power system that generates load voltage.


Upstream - On a ring network, the direction opposite to that of data flow. Also, the direction on the cable from the modem to the headend.


USE - A UL cable type. Underground service entrance cable, XLP or rubber-insulated, CSPE or XLP jacketed.


USOC (universal service order code) - An old Bell System term to identify a particular service or equipment offered under tariff.


UTP - Unshielded twisted pair. Two wires, usually twisted around each other to help cancel out induced noise in adjacent circuits. An unshielded twisted-pair cable usually contains four pairs in a single cable jacket.

V

V - Volts. The SI unit of electrical potential difference. One volt is the difference in potential between two points of a conducting wire carrying a constant current of one ampere when the power dissipated between these two points is equal to one watt. It represents the energy available per unit charge within an electrical system (joules /coulombs).


V band - A band of frequencies between 46 and 56 gigahertz.


V.10 - A CCITT interface recommendation; electrical characteristics for unbalanced double-current interchange circuits for use with integrated circuit equipment in the field of data communications. Electrically similar to RS-423.


V.11 - A CCITT interface recommendation; electrical characteristics for balanced double-current interchange circuits for use with integrated circuit equipment in the field of data communications. Electrically similar to RS-422.


V.20 - Parallel data transmission modems standardized for universal use in the general switched telephone network.


V.21 - A CCITT 300 bps dial modem recommendation for use in the general switched telephone network; similar to Bell 103.


V.22 - A CCITT 1,200 bps full-duplex 2-wire modem standardized for use in the general switched telephone network; similar to Bell 212.


V.22 bis - The worldwide standard for full-duplex 2-wire 2,400 bps modems (1,200 bps fall back), proposed by the CCITT and adopted by the telecommunications industry in 1984.


V.23 - A CCITT 5001 1,200 bps dial modem recommendation; similar to Bell 202.


V.24 - A CCITT interface recommendation that defines interchange circuits between data-terminal equipment and data circuit-terminating equipment; similar to and operationally -compatible with RS-232.


V.25 - A CCITT dial parallel interface recommendation.


V.25 bis - A CCITT dial serial interface recommendation.


V.25 ter - A CCITT 2,400 bps dial or 2-wire leased line modem recommendation.


V.26 - A CCITT 2,400/1,200 bps leased line modem recommendation; similar to Bell 201 B.


V.26 bis - A CCITT 2,400/1,200 bps dial line modem recommendation; similar to Bell 201 C.


V.27 - A CCITT 4,800 bps leased line modem recommendation with manual equalizer; similar to Bell 208 A.


V.27 bis - A CCITT 4,800/400 bps leased line modem recommendation with automatic equalizer.


V.27 ter - A CCITT 4,800 bps dial modem recommendation; similar to Bell 208 B.


V.28 - A CCITT interface recommendation that defines electrical characteristics for the interchange circuits defined by V.24; similar to and operationally compatible with RS- 232.


V.29 - A CCITT 9,600 bps leased line modem recommendation; similar to Bell 209.


V.32 - The worldwide standard for full-duplex 2-wire 9,600 bps modems (4,800 bps fall back), adopted in 1984. A V.32 modem must modulate signals at 9,600 by using QAM, it must transmit in full-duplex mode by using echo cancellation and it must be able to adjust its speed to match that of the answering modem.


V.35 - Data transmission at 48 kbps using 60 to 108 kHz group band circuits.


V.35 CCITT high-speed modem cable assembly, 34/C - Terminated with an M series 34-pin connector. Used to interconnect controllers, PCs, etc. to high speed modems.


V.42 bis - A worldwide standard for data compression in modems, adopted in 1989.


V.42 - A worldwide standard for error detection in modems, adopted in 1984. Enables error-free data transfer at speeds up to 19,200 bps without the need for leased lines.


VA - Volt-ampere. A designation of power in terms of volts and amperes. See APPARENT POWER.


VAR - A unit of reactive power that means volt-amperes, reactive.


VAR meter - An instrument used by power companies to measure the kVAR consumption. Utilities charge more for loads that consume large amount of reactive power.


VBR (variable bit rate) - One of the bit-rate modes available with MPEG compression. Will keep the image quality high even with increased motion but the bit rate will increase requiring,more bandwidth. Because of this, there is a need to insure that there is available bandwidth in the network to accommodate it.


VC - Varnished-cambric insulation.


VCSEL - Vertical-cavity surface-emitting laser is a type of semiconductor laser diode operating in the 850-nm wavelength window that is commonly used in Ethernet-based networks.


VDE - Association of German Electrical Engineers.


VELOCITY OF PROPAGATION - The transmission speed of an electrical signal down a length of cable compared to its speed in free space. Usually expressed as a percentage.


Vertical interval - The time of vertical retrace.


Vertical retrace - The return of the electron beam to the top of a television picture tube screen or a camera pickup device target at the completion of the field scan.


VFD cable - Variable frequency drive cable. A power cable specially designed for use with VFDs. Usually has three-phase conductors, three symmetrically positioned grounding conductors and an overall RF shield. Also called adjustable speed drive (ASD) cable.


VG - Varnished-glass or nylon braid, 600 V or 3,000 V, 130°C.


VGA (video graphics array) - An evolving video graphics standard that increases the video display, resolution from the current 640-by-350 pixel resolution to up to 640-by-480 pixel resolution. For many applications the VGA improvement in resolution isnít required, but for CAD/CAM applications, this represents a significant improvement in resolution.


VHF - Very high frequency. The band extending from 30 to 300 MHz as designated by the Federal Communications Commission.


Video motion detection - A system that uses the video signal from a camera to determine if there is any movement in the picture and set of an alarm.


Video pair cable - A transmission cable containing low-loss pairs with an impedance of 125 ohms. Used for TV pickups, closed-circuit TV, telephone carrier circuits, etc.


Video type lens - An auto iris lens without an internal circuit to control the iris. All iris control voltages come from a circuit located within the camera.


Viscosity - Internal friction or resistance to flow of a liquid: the constant ratio of shearing stress to rate of shear.


Virtual Circuit - 1. Provision of a circuit-like service by the software protocols of a network, enabling two end points to communicate as though via a physical circuit. 2. A circuit, generally established on demand that permits communication between two points without a direct, dedicated link between them.


VISCA (video system control architecture) - A machine-control protocol designed by Sony to allow synchronized control of up to seven Visa devices on a daisy chain.


VLAN (virtual LAN or logical LAN) - A network of computers that behave as if they are connected to the same wire even though they may actually be physically located on different segments of a LAN. VLANs are configured through software rather than hardware, which make them extremely flexible.


VLF - Very low frequencies. The band extending from 10 to 30 kHz, as designated by the Federal Communications Commission.


VOD - Video on demand.


Voice frequency (VF) - Describes an analog signal within the range of transmitted speech, typically supported by an analog telecommunications circuit.


Voice PABX, voice-only PABX - A PABX for voice circuits; a telephone exchange.


Voice/data PABX - A device that combines the functions of a voice PABX and a data PABX, often with emphasis on the voice facilities.


Voice-grade channel, voice-grade line - A channel or line that offers the minimum bandwidth suitable for voice frequencies, usually 300 to 3,400 bps.


Volt - A unit of electrical "pressure." One volt is the amount of electrical potential that will cause one ampere of current to flow through one ohm of resistance. Volt is a SI unit, the base units are joules (energy) per coulomb (charge) (J/C).


Voltage- Electrical potential or electromotive force expressed in volts.


Voltage breakdown - A test to determine the maximum voltage insulated wire can withstand before failure.


Voltage, cornoa extinction - The minimum voltage that sustains corona (partial discharge), determined by applying a corona producing voltage, then decreasing the voltage until corona is extinct.


Voltagedivider - A network consisting of impedance elements connected in series to which a voltage is applied and from which one or more voltages can be obtained across any portion of the network.


Voltage drop - The voltage developed across a conductor by the current and the resistance or impedance of the conductor. Also refers to the voltage used in a system to overcome the wiring resistance. Long runs of cable sized closely to the operating ampacity can suffer significant voltage drop that affects the load. Less than 5 percent is recommended by the NEC, around or less than 2 percent is ideal. Using larger conductor (less resistance) if possible will solve voltage drop problems.


Voltage, induced - A voltage produced in a conductor by a change in magnetic flux from an outside source.


Voltage rating - The highest voltage that may be continuously applied to a wire or cable in conformance with standards or specifications.


Voltage standing wave ratio (VSWR) - The ratio of the maximum effective voltage to the minimum effective voltage measured along the length of a mismatched radio frequency transmission line.


Voltage to ground - The voltage between an energized conductor and earth.


Volume resistivity - The resistance in ohms of a body of unit length and unit cross-sectional area.


VPN (virtual private network) - VPNs enable a customer to securely connect their offices using a protected ìtunnelî through a public infrastructure like the internet. They provide a more economical means to extend a corporate infrastructure and are an alternative to typical leased lines.


VSWR - See VOLTAGE STANDING WAVE RATIO.


VTL - Virtual tie line.


Vulcanization - A chemical reaction in which the physical properties of a polymer are changed by reacting it with cross-linking agents.


VW-1 - Vertical wire flame test. Formerly designated as FR1. A UL fire rating for single conductor cables. The test is described in UL Standard 1581.

W

W - (1) Symbol for watt or wattage. (2) A UL cable type. Heavy-duty portable power cable, one to six conductors. 600 V, without grounds.


Wall thickness - The thickness of a applied insulation or jacket. Generally wall thickness increases for higher voltages.


WAN (wide area network) - A network that uses common carrier-provided lines; contrast with LAN.


Water absorption - A test to determine the amount of water absorbed by a material after a given immersion period.


Water-blocked cable - A multiconductor cable having interstices filled with a water-blocking compound to prevent water flow or wicking.


Water-cooled leads - Furnace cables. High-energy cables. Usually welding cable strands cabled with a hose core for carrying coolant used in heavy-duty welding equipment, electric furnace applications, plating and various chemical processes.


Water treeing - A type of insulation deterioration that can occur after long-term immersion in water with an electrical stress applied.


Waterfall - The point at which cables installed horizontally in a tray transition to a vertical section of tray.


WATS (wide area telephone service watt) - A unit of electrical power. One watt is equivalent to the power represented by one ampere of current under a pressure of one volt in a DC circuit.


WATT - A unit of electrical power (energy consumed per unit time). One watt is equivalent to the power represented by one ampere of current under a pressure of one volt in a DC circuit.


Wave front - (1) That portion of an impulse (in time or distance) between the 10 percent point and the point at which the impulse reaches 90 percent of crest value. (2) The rising part of an impulse wave.


Waveform - 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.


Wavelength - The distance between the nodes of a wave. The ratio of the velocity of the wave to the frequency of the wave.


Waveshape representation - The designation of current or voltage by a combination of two numbers. For other than rectangular impulses: (a) virtual duration of the wave front in microseconds; and (b) time in microseconds from virtual zero to the instant at which one-half of the crest value is reached on the tail. For rectangular impulses: (a) minimum value of current or voltage; and (b) duration in microseconds.


WEEE - Waste Electrical and Electronic Equipment. A European Union regulation (Directive 2002/96/EC) which holds the manufacturer responsible for proper recycling or disposal when it reaches end-of-life. See also RoHS and REACH.


Weight resistivity - The resistance in ohms at a specified temperature of a copper wire of uniform cross section and of unit weight and unit length.


Welding - Joining the ends of two wires, rods or groups of wires: (a) by fusing, using the application of heat or pressure or both, by means of a flame torch, electric arc, or electric current; or (b) by cold pressure.


WEP (wired equivalent privacy) - A 128 bit wireless encryption scheme.


Wheatstone bridge - A device used to measure DC resistance. See BRIDGE.


Wi-Fi (wireless fidelity) - Meant to be used generically when referring of any type of 802.11 network whether 802.11b, 802.11a, dual-band, etc. The term is promulgated by the Wi-Fi Alliance. Wi-Fi Alliance is a nonprofit international association formed in 1999 to certify interoperability of wireless Local Area Network products based on IEEE 802.11 specification.


Wicking - The longitudinal flow of a liquid in a wire or cable due to capillary action.


Wideband - A communications channel offering a transmission bandwidth greater than a voice-grade channel. Synonymous with broadband.


Wire - A rod or filament of drawn or rolled metal whose length is great in comparison with the major axis of its cross section.


Wire cross-connect - The apparatus at which twisted pairs are terminated, to permit circuit rearrangement and testing. Cross-connects, usually located in equipment rooms and service closets, terminate house cables and station cables. Wire cross-connects in an ISN system employ either the traditional 66-type wiring or the newer 110-type wiring. The 66-type cross-connects use many single jumper wires for circuit administration and require a trained person with special tools to make connections. The 110-type cross-connect uses patch cords with molded, snap-on connectors allowing one-step administration of multiple wires and easy movement of connections; thus it permits customer participation, making it the preferred method in an ISN system.


Wire braid - Flexible wire constructed of small size strands in tubular form. Used for shielding or connections where constant flexing is required.


Wire Gauge (AWG) - The American Wire Gauge, originally called Brown & Sharpe Gauge. A system of numerical wire sizes starting with the lowest numbers for the largest sizes. Gauge sizes are each 20.6 percent apart based on the cross-sectional area.


Wire nut - A closed-end splice that is screwed on instead of crimped.


Wire-wrapped connection - A solderless connection made by wrapping bare wire around a square or rectangular terminal with a power or hand tool.


Wire wrapping tools - Portable electric tools and automatic stationary machines used to make solderless wrapped connections of wires to terminals.


Wiring block - A molded plastic block that is designed in various configurations to terminate cable pairs and establish pair location on a 110-type cross-connect.


Wiring closet - A room that contains one or more distribution racks and panels that are used to connect various cables together (via patch cables) to form physical networks. Termination point for customer premises wiring, offering access to service personnel; generally serves a specific area, with multiple wiring closets that are cross-connected.


Wiring concentrator - A lobe concentrator that allows multiple attaching devices access to the ring at a central point such as a wiring closet or in an open work area.


Withstand test voltage - The voltage that the device must withstand without flashover, disruptive discharge, puncture or other electric failure when voltage is applied under specified conditions.


Workstation - (1) Input/output equipment at which an operator works; (2) A station at which a user can send data to, or receive data from, a computer or other workstation for the purpose of performing a job.


WORM - Write once read many.


WP - Weatherproof construction for overhead wires.


WPA (Wi-Fi Protected Access) - A wireless security level higher than WEP.


Wrapper - An insulating barrier applied as a sheet of tape wrapped around a coil periphery.

X

X  - Symbol for reactance.


X band  - A band of frequencies between 5,200 and 10,000 megahertz.


X.121  - In packet-switched networks, a CCITT recommendation that defines the international packet-switched networks numbering scheme.


X.21  - (In PDNs) A CCITT recommendation that defines a digital interface, using the 15-pin connector described in V.11.


X.21 bis  - Use on public data networks of data terminal equipment that is designed for interacting to synchronous V-series modems; it is equivalent to RS-232 and V.24.



X.25  - A CCITT standard that defines the interface between a RDN and a packet-node user device (DTE); also defines the services that these user devices can expect from the X.25 PDN including the ability to establish virtual circuits through a PDN to another user device, to move data from one user device to another, and to destroy the virtual circuit when through.



X.28  - Defines the interface between PADs and non-packet mode OTEs.



X.29  - Defines the interface between PADs and packet-mode DTEs or other PADs.


X.3  - Describes the functions of the PAD and the various parameters which can be used to specify its mode of operation.



Xerox  - The originator of Ethernet.



XHHW  - A UL cable type. Cross-linked polyethylene insulated small diameter building wire rated 75°C wet and 90°C dry.



XHHW-2 - A UL cable type. Cross-linked polyethylene insulated small diameter building wire rated 90°C wet and dry.



XLP  - Cross-linked polyethylene. Also written XLPE.



XNS (Xerox Network System) - A set of protocols that defines the network and transport layers of a network.



XNS/ITP (Xerox Network Systemís Internet Transport Protocol) - In LAN technology, a special communications protocol used between networks. XNS/ITP functions at the 3rd and 4th layer of the OSI model. Similar to TCP/IP.



XON/XOFF  - 1. A form of software flow control in a DTE. A control character is transmitted over the primary data channel indicating that transmission should be suspended or reinstituted, depending upon the state of the DTEís buffers. 2. Control characters used for flow control.



XPM  - Cross-phase modulation (interchannel nonlinear effect).



X-ray - Penetrating short wavelength electromagnetic radiation created by electron bombardment in high-voltage apparatus; produce ionization when they strike certain materials.

Y

Yield strength - The point at which a substance changes from elastic to viscous.

Z

Z - Symbol for impedance.


Zero sequence impedance - The electrical impedance of a three-phase power cable under fault (short-circuit) conditions. It is typically 2.5 to 3 times the positive sequence impedance.


Zero-signal reference - A connecting point, bus or conductor used as one side of a signal circuit. May or may not be designated as a ground. Sometimes referred to as circuit common.


Zetabon - Dow's trade name for an acrylic acid copolymer coated aluminum tape.


Zipper tubing - Alpha's trade name for harnessing/jacketing material containing a zipper-track type closure. The zipper arrangement allows installation with no need to disconnect installed wire. See LOC-TRAC.


Zoom lens - A lens system that may be effectively used as a wide angle, standard or telephoto lens by varying the focal length of the lens.


Zoom ratio - The ratio of the starting focal length (wide position) to the ending focal length (telephoto position) of a zoom lens. A lens with a 10x zoom ratio will magnify the image at the wide angle end by 10 times.


ZWPF (zero water peak fiber) - A type of single-mode fiber for long-haul transmission systems that is designed to eliminate the water peak that causes the 1350-1450 nm wavelength range, within the fiber, to be unusable. ZWPF provides more usable wavelengths for DWDM and CWDM systems.


Zytel - DuPont's trademark for nylon resins.

0-9

0–10 V - A common analog process control signal voltage range.


1000BASE-CX - Two pairs of 150-ohm shielded twisted pair cable for a maximum length of 25 meters.


1000BASE-LX/LH - A long wavelength for a "long haul" fiber optic cable for a maximum length of 10 kilometers.


1000BASE-SX - A short laser wavelength on multimode fiber optic cable for a maximum length of 550 meters.



1000BASE-T - A form of Gigabit Ethernet (1 gigabit is 1,000 megabits per second) on copper cables, using four pairs of Category 5 unshielded twisted pair to achieve the gigabit data rate. 1000BASE-T can be used in data centers for server switching, for uplinks from desktop computer switches, or directly to the desktop for broadband applications. A big advantage of 1000BASE-T is that existing copper cabling can be used instead of having to rewire with optical fiber.



1000BASE-T - Four pairs of Category 5 unshielded twisted-pair cable for a maximum length of 100 meters. 1,000 Mbps over twisted pair.



1000BASE-ZX - An extended wavelength single-mode optical fiber for up to 100 kilometers.



100BASE-T - Also called "Fast Ethernet," it is a 100 Mbps version of Ethernet (IEEE 802.3u standard). 100BASE-T transmits at 100 Mbps rather than 10 Mbps. Like regular Ethernet, Fast Ethernet is a shared media LAN. All nodes share the 100 Mbps bandwidth. 100BASE-T uses the same CSMA/CD access method as regular Ethernet with some modification. Three cabling variations are provided. 100BASE-TX uses two pairs of Category 5 UTP, 100BASE-T4 uses four pairs of Category 3 and 100BASE-FX uses multimode optical fibers and is primarily intended for backbone use.



10BASE2  - A network conforming to the IEE 802.3 local area network standard. Also known as thinnet, 10BASE2 networks are a continuous bus configuration and are capable of carrying information at rates up to 10 Mbps. Devices are connected to the coaxial cable withB NC T connectors over distances up to 606.80 feet (185 m).



10BASE5  - A network conforming to the IEEE 802.3 local area network standard. Also known as standard Ethernet, 10BASE5 networks are a continuous bus configuration and are capable of carrying information at rates up to 10 Mbps. Devices are connected to the coaxial cable with transceivers over distances up to 1,640 feet (500 m).



10BASE-F - Operates over fiber on a star topology with a physical central hub acting as the network distribution point. Each node or workstation on the network is connected to the hub. Emerging standard under the IEEE 802.3 committee will use synchronous signaling theme, similar to Chipcom. Will also accommodate several ports of FOIRL compatible signaling.



10BASE-T - The implementation of the IEEE 802.2 standard designed to operate over a star topology with a central hub acting as the network distribution point. Each node or workstation on the network is connected to the hub by a link segment of unshielded twisted-pair cabling. The 10BASE-T standard limits unshielded twisted-pair segments to 100 meters.



10BROAD36  - 10 million bits per second over broadband coaxial cable with node-to-node coverage of 3600 meters. The IEEE 802.3 specification for running Ethernet on broadband.



10GBASE-T - A standard by the IEEE 802 committee to provide 10 Gigabit/second connections over conventional unshielded twisted-pair cables. The committee currently working on the standard is IEEE 802.3an, a subgroup of IEEE 802.3.



110-type connecting block - The part of 110-type cross-connect that terminates twisted-pair wiring and can be used with either jumper wires or patch cords to establish circuit connections.



110-type wiring - The distribution system hardware developed for Dimension System 85 and other current AT&T information systems. Originally known as 88-type wiring, it was refined over a ten-year period so that customers could participate in circuit rearrangement. The number 110 is part of a Western Electric product code.



1BASE-5 - Starlan.



3270, 3270 information display system  - A very popular IBM data entry and display system that consists of control units, display station, printers and other equipment.



4–20 mA  - A common analog process control signal current range.