Electronics Glossary Life Cycle: A test to determine the length of time before failure in a controlled, usually accelerated, environment. Light Commercial Building: A building or portion thereof that is intended for use with one to four (1-4) non-residential exchange access lines per tenant. Light-Intensity Ratio: (fiber optic) Ratio of input light intensity to the output light intensity. Light Source: (fiber optic) An object capable of emitting light. In fiber optics, the light source is normally an LED or a laser. Lightguide: (fiber optic) A flexible bundle of fibers used to transmit light. Lightwave Communications: (fiber optic) Communications using light to carry the information. Limits of Error: The maximum deviation (in degrees of percent) of a thermocouple or thermocouple extension wire from standard emf- temperature to be measured. Limpness: The ability of a cable to lay flat or conform to a surface. Line Balance: The degree to which the conductors of a cable are alike in their electrical characteristics with respect to each other, to other conductors and to ground. Line Drop: A voltage loss occurring between any two points in a transmission line, due to the resonance, reactance or leakage of the line. Line Loss: The total of the various energy losses occurring in a transmission line. Line Voltage: Voltage existing in a cable or circuit. Link: An assembly of telecommunications facilities between two points, not including terminal equipment. 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. 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. Modem: Device which places and receives data signals over a common carrier’s communication facility. 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. 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. 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). 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. 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. Low-Loss Dielectric: An insulating material that has a relatively low dielectric loss, such as polyethylene or Teflon®. Lossy Line: A cable having large attenuation per unit of length. 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. Micromicrofarad: One-millionth of a microfarad. (uuf, uufd, mmf, mmfd m-m F are common abbreviations.) Microfarad: One-millionth of a farad, commonly abbreviated m-F. 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. 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. Technical Information 186