165 Electronics Technical Information 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. Splice: A joining of conductors, generally from separate sheaths. Splice Closure: A device used to protect a cable or wire splice. Spread Spectrum: A modulation technique for multiple access, or for increasing immunity to noise and interference. Standing Wave: The stationary pattern of waves produced by two waves of the same frequency traveling in opposite directions on the same transmission line. Standing Wave Ratio (SWR): In a transmission line, waveguide, or analogous system, a figure of merit used to express the efficiency of the system in transmitting power. Star Topology: A topology in which each telecommunications outlet/connector is directly cabled to the distribution device. Stay Cord: A component of a cable used to anchor the cable ends at their points of termination and to keep any pull of the cable from being transferred to the electrical connections. Step Index Fiber: (fiber optic) A multimode fiber consisting of a core of uniform refractive index surrounded by cladding of slightly lower refractive index. Strand: One of the wires of any stranded conductor. Strand Lay: The distance of advance of one strand of a spirally stranded conductor, in one turn, measured axially. Stranded Conductor: A conductor composed of groups of wires twisted together. Strap: Square- or rectangular-section bare conductor manufactured and used in coil form. Strip: To remove insulation from a cable. Structural Return Loss: Backward reflected energies from uneven parts of the cable structure causing impedance variations are termed structural return loss. Surface Resistivity: The resistance of a material between two opposite sides of a unit square of its surface. It is usually expressed in Ω. Surge: A temporary and relatively large increase in the voltage or current in an electric circuit or cable. Also called Transient. Suspended Ceiling: See False Ceiling. Sweep-test: Pertaining to cable, the frequency response is verified by generating an rf voltage whose frequency is swept repeatedly through a given frequency range at a rapid constant rate while the cable response is observed. 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. Tank Test: A voltage dielectric test in which the test sample is submerged in water and voltage is applied between the conductor and water as ground. Tape: A relatively narrow woven or cut strip of fabric, paper or film material. Tape Cable: A form of multiple conductor consisting of parallel metal strips imbedded in insulating material. Tape Wrap: A spirally applied tape over an insulated or uninsulated wire. Taped Insulation: Insulation of helically wound tapes applied over a conductor or over an assembled group of insulated conductors. Taping: Process of insulating continuous length, large diameter wires with tape of non- extrudable materials. TB: Terminal Block Tear Strength: The force required to initiate or continue a tear in a material under specified conditions. Teflon®: DuPont company trade name for fluorocarbon resins. FEP, PFA and TFE are typical materials. Tefzel®: DuPont trade name for a fluorocarbon material typically used as a wire wrap insulation. Telecommunications: The communication of information over some distance, including interbuilding and intrabuilding distances. Telecommunications Closet: See Closet, Telecommunications. Telecommunications Entrance Facility: See Entrance Facility, Telecommunications. Telecommunications Entrance Point: See Entrance Point, Telecommunications. Telecommunications Entrance Room or Space: See Entrance Room or Space, Telecommunications. Telecommunications Equipment Room: See Equipment Room, Telecommunications. Telecommunications Grounding Busbar: A common point of connection for telecommunications system and bonding to ground, which is located in the telecommunications closet or equipment room. Telecommunications Infrastructure: See Infrastructure, Telecommunications. Telecommunications Outlet/Connector: See Outlet/Connector, Telecommunications. Telemetry Cable: Cable used for transmission of information from instruments to the peripheral recording equipment. Temperature Rating: The maximum temperature at which an insulating material may be used in continuous operation without loss of its basic properties. Tensile Strength: The pull stress required to break a given specimen. Tension Member: A member included in a fiber cable to add tensile strength. Terminal: (1) A point at which information may enter or leave a communications network; (2) the input-output associated equipment; or (3) a device by means of which wires may be connected to each other. Termination Hardware: This term is outmoded. See Connecting Hardware. Test Lead: A flexible, insulated lead wire used for making tests, connecting instruments to a circuit temporarily or for making temporary electrical connections. Textile Braid: Any braid made from threads of cotton silk, or synthetic fibers. Thermal Aging: Exposure to a thermal condition or programmed series of conditions for predescribed periods of time. Thermocouple Lead Wire: An insulated pair of wires used from the couple to a junction box. Thermoplastic: A material which softens when heated and becomes firm on cooling. Thermoset: A material which hardens or sets when heat is applied, and which, once set, cannot be resoftened by heating. The application of heat is called “curing.” 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-Wire System: A d-c or single-phase a-c system comprising three conductors, one of which is maintained at a potential midway between the potential of the other two. Tin Overcoat (TOC): Tinned copper wire, stranded, then coated with pure tin. Tinsel Wire: A low-voltage stranded wire, with each strand a very thin conductor ribbon spirally wrapped around a textile yarn. Topcoat: Bare (untinned) copper wire, stranded then coated with pure tin. Topology: The physical or logical arrangement of a telecommunications system. Tracer: A means of identifying polarity. Transducer: A device for converting mechanical energy to electrical energy. Transfer Impedance: The ratio of the source voltage of the wires inside the cable to the shield current of the cable or connectorized cable assembly. Transition Point: A location in the horizontal cabling where flat undercarpet cable connects to round cable. Transmission: Transfer of electric energy from one location to another through conductors or by radiation or induction fields. Transmission Cable: Two or more transmission lines. See Transmission Line. Transmission Line: An arrangement of two or more conductors or a wave guide used to transfer signal 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 or data signals. Typically, wire cable includes twisted pair, coaxial and twinaxial. Optical fiber cable includes single, dual, quad, stranded and ribbon (Al). Transmitter: The electronic package that injects an electrical signal or light signal over the transmission medium. Transparent: (fiber optic) Transmitting rays of light so that objects can be seen through the material. 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 Cable: A factory-assembled multiconductor or multipair control cable approved under the National Electrical Code for installation in trays. Triaxial: A three-conductor cable with one conductor in the center, a second circular conductor shield concentric with the first, and third circular conductor shield insulated from and concentric with the first and second, usually with insulation, and over a braid or 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. Glossary
