Wire and Cable Standards

Section VIII: Glossary

ANSI: American National Standards Institute

Administration: correct and consistent use of color, labeling, and numbering when preparing and maintaining records of wire and cable work.

Access Point (AP): The central or control point in a wireless cell that acts as a bridge for traffic to and from wireless devices in the cell. The AP also connects wireless devices to the wired portion of the LAN.

Americans with Disabilities Act (ADA): U.S. Department of Justice regulations and guidelines under civil rights law that ensure individuals with disabilities have access to, or may use, public entities and government buildings.

American Wire Gauge (AWG): The standard gauge for measuring the diameter of copper, aluminum, and other conductors.

Approved Ground: A ground that has been approved for use by the authority having jurisdiction.

As-built: Documentation that indicates cable routing, connections, systems, and blueprint attributes upon job completion that reflects changes from the planned to the finished state

Attenuation: The effect of signal dwindling, experienced with accumulating line length or distance of radio transmission.

Authority having jurisdiction (AHJ): The building official, electrical inspector, fire marshal, or other individuals or entities responsible for interpretation and enforcement of local building and electrical codes.

Backbone(s): The part of a premises distribution system that included a main cable route and facilities for supporting the cable from the equipment room to the upper floors or along the same floor to the wiring closets.

Backboards: fire-treated 3/4" plywood panels used to mount termination blocks at the IDF and MDF.

Basic rate interface (BRI): The simplest form of network access available on (BRI) the ISDN (integrated services digital network). The BRI comprises 2B + D channels for carriage of signaling and user information.

Bend Radius: The radius of curvature that fiber or copper can bend without breaking or causing excessive loss.

Buffer tube: Loose-fitting cover over the optical fibers in loose-tube construction, used for protection and isolation.

Building distribution: horizontal and vertical wiring that comprise the Riser System and the horizontal distribution used to connect the station outlets through the IDF's and back to the building's MDF.

Building Entrance Facility: A facility that provides all necessary mechanical and electrical services, that complies with all relevant regulations, for the entry of telecommunications cables into a building.

Cable Fill: The ratio of cable installed into a conduit against the theoretical maximum capacity of the conduit.

Cabling: A system of telecommunications cables, cords and connecting hardware that can support the connection of information technology equipment.

Campus wiring: general plan for connecting Harvard buildings via buried conduit and steam tunnels. Campus wiring enables the copper (or fiber optic) cables to connect Harvard buildings to each other and back to the main switch.

Category 5e: This is an enhanced version of Category 5, with additional parameters specified to enable parallel transmission with full duplex across the four pairs. Enhanced Category 5 specifications for cable and connecting hardware products with transmission characteristics specified to 100 MHz, intended to support digital transmission of 1000 Mb/s.

Category 6: For cable and connecting hardware products with transmission characteristics specified to 250 MHz, used to support digital transmission of 1 Gbp/s and above.

Ceiling distribution: Distribution system that uses the space between the false or suspended ceiling and the structural ceiling for housing horizontal cable routes.

Channel: The end-to-end transmission path connecting any two pieces of application-specific equipment. Equipment cables and work area cables are included in the channel.

Cladding: The low refractive index material that surrounds the core of an optical fiber, usually pure silica.

Conduit: heavy-duty casing used to enclose and conceal wire and provide additional protection for wires. Conduits should be sized for all potential voice and data communication needs.

Coaxial (Ethernet) cable: 2-conductor cable with a copper wire center conductor and another tubular conductor of braided wire or copper tubing.

Cords: A short length of copper wire or fiber optic cable with connectors on each end. Used to connect equipment to cabling or to connect cabling segments.

Coring: drilling between floors of a building when IDF closets are aligned vertically. Also, drilling through a building's external wall to provide access for a 4-inch conduit that terminates in the basement MDF.

Cross-Connect: action of joining wires (vertical and horizontal) at the IDFs and MDF to provide service for the station outlet back from the main switch. Cross-connects are performed using standard tools and are labeled at each location according to the specifications described in this document.

Crosstalk: An electromagnetic coupling between two physically isolated circuits in a system. This coupling causes a signal on one circuit to induce a noise voltage on adjacent circuits. Thereby causing interference.

Customer premises equipment (CPE): Customer owned equipment used to terminate or process information for the public network.

CMR: fire rating approved by the National Fire Protection Association (NFPA) for riser cable.

CMP: fire rating approved by NFPA for plenum cable.

Decibel (dB): A unit used to measure relative increase or decrease in power, voltage or current, using a logarithmic scale.

Decibel/kilometer (dB/km): A unit of measurement for fiber optic attenuation.

Demarcation point (DP): A point where the operational control or ownership changes. This point is usually where the access provider's facilities stop and the customer-owned structured cabling begins.

Distribution media: types of wire used to link Network equipment (telephone, PC, terminal) to the main Intellipath system or local area network (LAN). Various types of media may be used in one Distribution System.

EIA/TIA: Electronic Industry Association/Telecommunications Industry Standard. Used for testing Category 5 UTP.

Equal Level Far End Crosstalk (ELFEXT): Is the same as FEXT, except that the coupled signal at the remote end is relative to the attenuated signal at the remote end on the pair the signal was applied to at the local end.

Equipment (Telephone) room: space (usually in the basement of a building) where dial tone or transmission service is brought into the building, campus wiring is terminated, and wiring is distributed throughout the building.

Far End Crosstalk (FEXT): Refers to the undesired coupling of signals from the transmit pair onto the receive pair at the other (=far) end. FEXT isolation is also expressed in dB. For some applications this is an important parameter, for most applications however, the NEXT values are more important.

FDDI: Fiber Distributed Data Interface. An American National Standards Institute (ANSI) standard for fiber-based token ring physical and data link protocol that operates at 100Mbps data transfer rate.

Fiber optic cable: thin glass filaments that transmit signals as very high-frequency light pulses.

Firestop: A material, device, or assembly of parts in an architectural barrier to prevent vertical or horizontal passage of flame, smoke, water, or gases through the rated barrier.

Firestop system: A specific construction consisting of the material(s) (firestop penetration seals) that fill the opening in the wall or floor assembly, and around and between any items that penetrate the wall or floor (e.g., cables, cable trays, conduit, ducts, pipes), and any termination devices (e.g., electrical outlet boxes), along with their means of support.

Firestopping: The process of installing specialty materials into penetrations of fire-rated barriers to re-establish the integrity of the barrier.

Firewall: 1. A wall that helps prevent fire spreading from one fire zone or area to another, and that runs from structural floor to structural ceiling. 2. One or more security mechanisms designed for access control and authentication to prevent, detect, suppress, and/or contain unauthorized access to a network. Firewalls are designed to keep unwanted and unauthorized traffic from a protected network.

Fishtape: A tool or device that can be extended from the beginning of a pathway to the other end to assist in installing a pull line or to pull in a cable.

Harvard University Network (HUN): an integrated communication transport system, which provides voice and data services to the University, composed of Intellipath, High-speed Data Network (HSDN), TFMS, and wire and cable.

Horizontal distribution (also called station wiring): wires connecting the station outlet (jack) to the IDF.

High-speed Data Network (HSDN): fiber optic backbone and associated media and equipment used to provide mainframe-to-mainframe, mini-to-mini, LAN-to-station, or LAN-to-LAN connectivity within and outside Harvard, as well as access to national networks.

Hub: A concentrator or repeater in a star topology at which node connections meet.

Hybrid cable: An assembly of two or more different types of cable units, cables or categories covered by an overall sheath, It may be covered by an overall shield.

IDF (Intermediate Distribution Frame): area, or one of the areas in a building, housing the riser cable terminations for the floor on which it is located, and from which the service is distributed to the station locations via the horizontal distribution system.

Integrated services digital network (ISDN): Integrated voice and data network based on digital communications technology and standards interfaces.

Intellipath: digital Centrex used at Harvard to provide voice and data services. Control and switching modules are housed at New England Telephone (NET), 1230 Soldiers Field Road, Boston.

Inter-building wire and cable: support network of copper and fiber optic cable providing high-speed and low-speed data transport between locations.

Interference: A signal impairment caused by the interaction of another unwanted signal.

Jack (also called station outlet): wire termination assembly that allows network equipment to connect to University Network voice and data services.

J-hook: A supporting device for horizontal cables that is shaped like a J. It is attached to some building structures. Horizontal cables are laid in the opening formed by the J to provide support for the cables.

LAN (local area network): association of personal computer or workstation users who share information and communicate via the University Network's distribution system, inter-building cable, and related network server equipment. LAN users may access the HSDN (High-speed Data Network) for high speed access to file servers, data bases, and other LANs both within and outside the University.

Megabits per second (Mb/s): A unit of measure used to express the data transfer rate of a system, device, or communications channel.

Megahertz (MHz): A unit of frequency equal to one million cycles per second (hertz).

MDF (Main Distribution Frame ‚ also called equipment room): usually located in a building's basement, where dial tone is brought into the building, campus wire is terminated, and wire is distributed through the building.

Multimode fiber: Optical fibers that have a large core and that permit nonaxial rays or modes to propagate through the core. 62.5 micron is the common standard core size for premises cabling systems.

National Electrical Code (NEC): A nationally recognized safety standard for the design, construction, and maintenance of electrical circuits. The NEC, sponsored by the National Fire protection Association (NFPA), generally covers electrical power wiring within buildings.

Network components: individual systems (TFMS, Intellipath, wire and cable, and HSDN) that function together to operate, manage, and support the Harvard University Network.

Network equipment: terminals or other equipment located at the station, connected to the Network via a jack, or connected to the Network through the wiring closet. This equipment may include a personal computer, terminal, telephone, fax machine or modem.

Near End Crosstalk (NEXT): Refers to the undesired coupling of signals from the transmit pair onto the receive pair on the same (=near) end. NEXT isolation is expressed in dB and is a measure of how well the pairs in a cable are isolated from each other.

NFPA: National Fire Protection Association.

Noise: The term used for spurious signals produced in a conductor by sources other than the transmitter to which it is connected. Noise can affect a legitimate signal to the extent that it is inaccurate or indecipherable when it reaches the receiver. The higher the speed of data transmission, the worse the effects of noise become.

110 Hardware: type of termination block used to cross-connect vertical and horizontal distribution at IDF and MDF locations.

Optical fiber: A transmission medium consisting of a core of glass or plastic surrounded by a protective cladding. Signals are transmitted as light pulses introduced into the fiber by a light transmitter i.e. Laser or an LED.

Outlets: A term used to describe the sockets provided in the work location of a structured cabling system. These are usually 8-pin modular sockets which can support a variety of services e.g. voice, video and data.

Patch cord(s): Flexible cable unit or element with connector(s), used to establish connections on a patch panel.

Patch panel(s): Termination and administration hardware designed to accommodate the use of patch cords. It facilitates administration for moves and changes.

Pathway(s): Designated cable routes and/or support structures in a false floor or ceiling.

Permanent link: The transmission path between two mated interfaces of generic cabling, excluding equipment cables, work area cables and cross-connections.

Plenum: A designated area used for transport of environmental air as part of the air distribution system. Because it is part of the air distribution system, cables installed in this space require a higher fire rating.

Plenum cable: A cable with flammability and smoke characteristics that meet the safety requirements of the National Electrical Code® (NEC®) that allow it to be routed in a plenum area without being enclosed in a conduit.

Plenum rated: Meeting flammability and smoke requirements for the purpose of fire, life, and safety as described by the National Electrical Code® (NEC®).

Point of demarcation (DP): A point at which two services may interface and identify the division of responsibility (e.g., the point inside a commercial building where the location service provider stops and the customer's cabling begins).

Poke-thru: A penetration through the fire-resistive floor structure to permit the installation of electrical and/or communications cables

Pre-wiring: Wiring installed before walls are enclosed or finished.

PVC (Poly-vinyl chloride): type of cable used in areas with non-plenum ceilings. The minimum type of PVC required is: UL-listed CMR/CMP semi-rigid PVC.

Proprietary networks: Networks that are not designed or installed to standard based guidelines and do not relate specifically to any relevant standard.

Raceway system: system for distribution of media and equipment, including trays, conduit, and wire mold that can carry concealed wire between non-aligned telephone closets and may, in some situations, extend to the station location.

Riser system (also called vertical distribution): how media is distributed among floors of a multi-story building.

Router(s): An intermediate system between two or more networks capable of forwarding data packets at the network layer (layer 3.)

Server(s): Host computer(s.)

Singlemode: Optical fiber with a small core diameter in which only singlemode is capable of propagation. 8.3 micron is the common standard core size.

Sleeve (SL): A short section of conduit, either metallic or non-metallic, lining an opening in the wall or floor for cables to pass through.

Splice: A joining of conductors or fibers, generally from separate cables.

Standards: set of guidelines used as a framework for installing wire and cable for voice and data transmission at Harvard.

Station (STA): Telecommunications end-user location. Usually dedicated to a single-user location and function (e.g., a telephone or computer hookup work area outlet).

Station wiring (also called horizontal distribution): describes wires that connect station outlets (jacks) to the IDF.

Structured cabling: Flexible cabling scheme which allows rapid reconfiguration for office moves through patching.

Systimax SCS: Brand name of Avaya's structured cabling system.

Telecommunications closet: An enclosed space for housing telecommunications equipment, cable terminations, and cross-connect cabling. The telecommunications closet is a recognized cross-connect point between the backbone and horizontal cabling subsystems.

Telecommunications bonding backbone (TBB): A conductor that interconnects the telecommunications main grounding busbar (TMGB) to the telecommunications grounding busbar (TGB).

Telecommunications bonding backbone interconnecting bonding conductor (TBBIBC): A conductor utilized to interconnect two or more telecommunications bonding backbones.

Telecommunications bonding equipment conductor (TBEC): Should be installed from each piece of equipment to the telecommunications grounding busbar or telecommunications main grounding busbar.

Telecommunications grounding busbar (TGB): A common point of connection for telecommunications system and equipment bonding to ground; located in the telecommunications room or equipment room.

Telecommunications main grounding busbar (TMGB): A busbar placed in a convenient and accessible location and bonded, by means of the bonding conductor for telecommunications, to the building service equipment (power) ground.

Telecommunications outlet (TO): A socket where the horizontal cable terminates. The telecommunications outlet provides the interface to the work area cabling.

Terminal equipment: telephones, data communication equipment, and peripherals used at station locations.

Terminal wiring: wires connecting network equipment (PC, telephone, or terminal) to the jack on the wall.

Termination blocks: location of the cross-connect fields used to connect and administer station wire. The standard required at Harvard is the 110A (AT&T) Termination block.

Teflon: material required as a casing for cables in areas with plenum ceilings.

Twisted pair: two insulated copper wires twisted together, with a 4-pair total sharing a common outer insulation or sheath; 24 gauge.

UL: Underwriters Laboratory.

Unshielded twisted pair cable (UTP): An electrically conducting cable comprising one or more pairs none of which is shielded.

Wire and cable: media system using copper twisted pair, fiber optic cable, and/or coaxial used to distribute voice and data services throughout the University. Its two principle components are media (the type of wire used by each station to transmit voice and data) and distribution (the elements needed to link the stations to the media switch or LAN).

Wireless LAN: Local area network that communicates using radio technology.

Work area: A building space where the occupants interact with telecommunications terminal equipment. A user's work area, which is typically 9 sq. meters or 100 sq. feet.