162 Technical Information Electronics Listed: Equipment included in a list published by an organization, acceptable to the authority having jurisdiction, that maintains periodic inspection of production of listed equipment, and whose listing states either that the equipment or material meets appropriate standards or has been tested and found suitable for use in a specified manner. Local Area Network (LAN): A geographically limited communications network intended for the local transport of data, video and voice. Longitudinal Shield: A tape shield, flat or corrugated, applied longitudinally with the axis of the core being shielded. Longitudinal Wrap: Tape applied longitudinally with the axis of the core being covered. Loop Resistance: The total resistance of two conductors measured round-trip from one end. Commonly used term in the thermocouple industry. Looping-in: Wiring method which avoids tee joints by carrying the conductor or cable to and from the point to be supplied. Loss: Energy dissipated without accomplishing useful work. Loss Factor: The product of the dissipation and dielectric constant of an insulating material. Lossy Line: A cable having large attenuation per unit of length. Low-Loss Dielectric: An insulating material that has a relatively low dielectric loss, such as polyethylene or Teflon®. Low-Noise Cable: Cable configuration specially constructed to eliminate spurious electrical disturbances caused by capacitance changes or self-generated noise induced by either physical abuse or adjacent circuitry. Low Tension: Low voltage, as applied to ignition cable. Lug: Termination, usually crimped or soldered to the conductor, with provision for screwing on to the terminal. m: Meter. Magnet Wire: Insulated wire intended for use in windings on motor, transformer and other coils for electromagnetic devices. Magnetic Field: The region within which a body or current experiences magnetic force. Magnetic Flux: The rate of flow of magnetic energy across or through a surface (real or imaginary). Magnetic Noise: Caused by change in current level, e.g. ac powerline (creates magnetic field around the cable) this magnetic field causes the magnetic noise. Main Cross-Connect: A cross-connect for 1st level backbone cables, entrance cables and equipment cables. Marker Tape: A tape laid parallel to the conductors under the sheath in a cable, imprinted with the manufacturer’s name and the specification to which the cable is made. Master Antenna Television (MATV): A combination of components providing multiple television receiver operations from one antenna or group of antennas normally on a single building. Material Scattering Loss: (fiber optics) Loss due to fluctuations in the refractive index and to inhomogeneities in material composition and temperature. Media, Telecommunications: Wire, cable or conductors used for telecommunications. Megarad: A unit for measuring radiation dosage. Messenger: Supporting member, usually a high- strength steel wire, used to suspend aerial cable. The messenger may be an integral part of the cable, or exterior to it (lashed messenger). Microbending Loss: (fiber optic) Loss due to small geometrical irregularities along the core- clad interface of the fiber. Microfarad: One-millionth of a farad, commonly abbreviated m-F. Micromicrofarad: One-millionth of a microfarad. (uuf, uufd, mmf, mmfd m-m F are common abbreviations.) Microwave: A short (usually less than 30 cm.) electrical wave. Mil: A unit used in measuring diameter of a wire or thickness of insulation over a conductor. One-one thousandth of an inch (.001”). Mineral-Insulated: Cable and thermocouple wire consisting of one or more conductors surrounded by magnesium oxide insulation and enclosed in a liquid- and gas-tight metallic sheathing. Miniature Wire: Insulated conductors of approximately 20-34 AWG. Mis-Match: A termination having a different impedance than that for which a circuit or cable is designed. Mode: One of the components of a general configuration of a propagating wave front. Modem: Device which places and receives data signals over a common carrier’s communication facility. Modular Jack: This term is outmoded; see Outlet/Connector, Telecommunications. Modular Plug: A telecommunications connector for wire or cords per the Part 68 Rules. A modular plug can have 6 or 8 contact positions, but not all the positions need be equipped with contacts. Modulation: A process whereby certain characteristics of a wave, often called the carrier, are varied or selected in accordance with a modulating function. Modulus of Elasticity: The ratio of stress to strain in an elastic material. Moisture Absorption: The amount of moisture, in percentage, that a material will absorb under specified conditions. Moisture Resistance: The ability of a material to resist absorbing moisture from the air or when immersed in water. Molded Plug: A connector molded on either end of a cord or cable. Monomer: The basic chemical unit used in building a polymer. Motor Lead Wire: Wire which connects to the fragile magnet wire found in coils, transformers and stator or field windings. Multiconductor: More than one conductor within a single cable complex. Multimode Optical Fiber: An optical fiber that will allow many bound modes to propagate. The fiber may be either a graded-index or step- index fiber. See also: Optical Fiber Cable. Multiple Conductor Cable: A combination of two or more conductors cabled together and insulated from one another and from sheath or armor where used. Multiple Conductor Concentric Cable: An insulated central conductor with one or more tubular stranded conductors laid over it concentrically and insulated from one another. Multiplexing: Simultaneous transmission of two or more messages over the same cable pair. Mutual Capacitance: Capacitance between two conductors when all other conductors are connected together to shield and ground. Mylar®: DuPont trademark for polyester film. Nanometer (nm): One billionth of a meter (10 –9 meter). Nanosecond: One billionth of a second (10 -9 seconds). National Electric Code (NEC): A set of regulations governing construction and installation of electrical wiring and apparatus in the United States, established by the American National Board of Fire Underwriters. Neoprene: A synthetic rubber with good resistance to oil, chemical and flame. Also called polychloroprene. Noise: In a cable or circuit, any extraneous signal which tends to interfere with the signal normally present in or passing through the system. Nomex®: DuPont trademark for a temperature- resistant, flame-retardant nylon. Non-Contaminating: Type of PVC jacket material whose plasticizer will not migrate into the dielectric of a coaxial cable and thus avoids contaminating and destroying the dielectric. Nylon: Thermoplastic with good chemical and abrasion resistance. NVP: Nominal Velocity of Propagation. Off Center: Conductor displaced within the cross-section of its insulation. Offgassing: Percentage of a specified gas released during the combustion of insulation or jacketing material. Ohm: A unit of electrical resistance. Oil Aging: Cable aged in an accelerated manner by placement in an oil bath and heated to a pre-set temperature for a stated time. Oil-Filled Cable: A self-contained pressure cable in which the pressure medium is low viscosity oil having access to the insulation. Opaque: (fiber optic) Not permitting the passage of light. Open Cell: Foamed or cellular material with cells which are generally interconnected. Optical Communication Cable: (fiber optic) Fiber with a protective jacket around it. Optical Conductors: (fiber optic) Materials which offer a low optical attenuation to transmission of light energy. Optical Fiber Cable: An assembly consisting of one or more optical fibers. Optical Fiber Duplex Adapter: A mechanical media termination device designed to align and join two duplex connectors. Optical Fiber Duplex Connector: A mechanical media termination device designed to transfer optical power between two pairs of optical fibers. Optical Waveguide: (fiber optic) A fiber used for optical communications. Analogous to a waveguide used for microwave communications. Oscillatory Surge: A surge which includes both positive and negative polarity values. Outgassing: The dissipation of gas from a dielectric evidencing decomposition. Outlet Box, Telecommunications: A metallic or nonmetallic box mounted within a wall, floor or ceiling and used to hold telecommunications outlet/connectors or transition devices. Glossary
