Cabling – Definitions Essay
Cabling – Definitions
Horizontal Cable- The cabling between and including the telecommunications outlet and the horizontal cross-connect. Backbone Cable- A cable connection between telecommunications or wiring closets, ﬂoor distribution terminals, entrance facilities, and equipment rooms either within or between buildings. Patch Cords- Any ﬂexible piece of cable that connects one network device to the main cable run or to a patch panel that in turn connects to the main cable run. Connectors- With respect to cabling, a device attached to the end of a cable, receiver, or light source that joins it with another cable, device or ﬁber. A connector is a mechanical device used to align and join two conductors or ﬁbers together to provide a means for attaching and decoupling it to a transmitter, receiver, or another ﬁber. Conduit- A rigid or ﬂexible metallic or nonmetallic raceway of circular cross section in which cables are housed for protection and to prevent burning cable from spreading ﬂames or smoke in the event of a ﬁre. Racks- A frame-like structure where patch panels, switches, and other network equipment are installed. The typical dimension is 19 inches.
Punch-Down Blocks- A generic name for any cross-connect block where the individual wires in UTP are placed into a terminal groove and “punched down” with a special tool. The groove pierces the insulation and makes contact with the inner conductor. Consolidation Points- A location deﬁned by the ANSI/TIA/EIA-568-B standard for interconnection between horizontal cables that extends from building pathways and horizontal cables that extend into work area pathways. Crimpers- A device that is used to install a crimp-on connector. Crimping involves the act of using the crimping tool to install the connector. Fish Tape- Also called ﬁsh cord. A tool used by electricians to route new wiring through walls and electrical conduit. Cable Toner- Device that ensures electricity is going where it needs, and isn’t being lost in an unintended place. Continuity Tester- Ensures that there is an uninterrupted pathway for electrical or optical signals. Category 5e/6 Cable- Recognized in ANSI/TIA-568-C. Category 5e has improved speciﬁcations for NEXT, PSNEXT, Return Loss, ACRF (ELFEXT), PSACRF (PS-ELFEXT), and attenuation as compared to Category 5. Recognized in ANSI/TIA-568-C, Category 6 supports transmission at frequencies up to 250MHz over 100 ohm twisted pair.
Binder Groups- A group of 25 pairs of wires within a twisted-pair cable with more than 25 total pairs. The binder group has a strip of colored plastic around it to differentiate it from other binder groups in the cable. Hybrid/Composite Cable- A cable that contains ﬁber, coaxial, and/or twisted-pair conductors bundled in a common jacket. May also refer to a ﬁber-optic cable that has strands of both single-mode and multimode optical ﬁber. Pulling Cable- A string that is tied to a cable and is used to pull cables through conduits or over racks. Similar to ﬁsh tape. Wavelengths of Light- With respect to optical ﬁber communications, the distance an electromagnetic wave travels in the time it takes to oscillate through a complete cycle. Wavelengths of light are measured in nanometers or micrometers. EMI- Electrical noise generated in copper conductors when electromagnetic ﬁelds induce currents. Copper cables, motors, machinery, and other equipment that uses electricity may generate EMI. Optical-Fiber Strand- A thin glass strand designed for light transmission.
A single hair-thin fiber is capable of transmitting trillions of bits per second. In addition to their huge transmission capacity, optical fibers offer many advantages over electricity and copper wire. Index of Refraction- The ratio of the speed of light in a vacuum to the speed of light in a given transmission medium. This is usually abbreviated n. Cable Jacket- A covering over the core assembly that may include one or more metallic members, strength members, or jackets. Cladding Size- Name for the material (usually glass, sometimes plastic) that is put around the core of an optical ﬁber during manufacture. The cladding is not designed to carry light, but it has a slightly lower index of refraction than the core, which causes the transmitted light to travel down the core.
The interface between the core and the cladding creates the mode ﬁeld diameter, wherein the light is actually held reﬂectively captive within the core. Multifiber Cables- Used to interconnect ﬁber-optic patch panels from point to point. Differential Mode Delay- A transmission scheme where voltages appear equal in magnitude and opposite in phase across a twisted-pair cable with respect to ground. Differential mode transmission may also be referred to as balanced mode. Chromatic Dispersion- The spreading of a particular light pulse because of the varying refraction rates of the different colored wave-lengths.