Standard mounting height or vertical distance for a fixture, ceiling, device, or any other object measured from the finished floor surface to the center-line of the object as the measurement point.
Telecommunications cable installed on aerial supporting structures including poles, side of buildings and other structures.
A system consisting of completely removable and interchangeable floor panels that are supported on adjustable pedestals or stringers (or both) to allow entry to the area beneath.
A stand-alone hardware device or a computer wireless adapter with software that acts as a wireless communication hub for users with wireless devices to connect to each other and to bridge those devices to the cabled portion of the network.
Small, flexible plastic microduct tubing installed prior to the installation of individual or multiple optical fibers that are blown in through the microduct using compressed air.
Unwanted coupling of signals into a balanced twisted-pair in a given cable from one or more balanced twisted-pair(s) external to that given cable.
A system used to specify wire size. The greater the wire diameter, the smaller the AWG value. Historically, the AWG number has represented the number od drawings processes applied to a give wire during manufacturing.
A material with exceptional tensile strength and cooefficient of thermal expansion near that of glass. Use as a strength member in optical fiber cables.
A digital service designed to provide high data transfer rates over traditional telephone cable. Asymmetric refers to different speeds for uplink and downlink traffic.
Technology selected by the International Telecommunications Union (ITU, formerly CCITT) for broadband ISDN. This communications protocol is also specified by the ATM Forum (Foster City, CA) for 155 Mb/s transmission over twisted-pair cable and various bit rate optical fiber cabling applications. Uses fixed-length (53-byte) packets called cells to carry all types of traffic (e.g., voice, data, still image, audio/video).
A reduction in power or amplitude of the transmitted signal. In cables, it is generally expressed in decibels per unit length.
The difference between attenuation and crosstalk measured in decibels.
The entities responsible for interpretation and enforcement of local building and electrical codes.
A device usually located within the tenant or living unit used to terminate the ADO cable or backbone cable.
Cable and connecting hardware that comprise the main and intermediate cross-connects, as well as cable runs that extend between telecommunications rooms, equipment rooms and entrance facilities.
An indication of signal voltage equality and phase polarity on a conductor pair. Perfect balance occurs when the signals across a twisted-pair are equal in magnitude and opposite in phase with respect to ground.
Two voltages, equal and opposite in phase with respect to each other, across the conductors of a twisted-pair (commonly referred to as tip and ring).
An impedance matching transformer used to convert unbalanced coaxial signals to balanced signals.
A range of frequencies, usually the difference between the upper and lower limits of the range, typically expressed in megahertz (MHz). It is used to describe the information-carrying capacity of a medium. In copper and optical fibers, the bandwidth decreases with increasing length. Optical fiber bandwidth is specified in megahertz kilometers (MHz-km).
A transmission technique in which all of the available bandwidth is dedicated to a single communications channel. Only a single message transfer can occur at a given time.
An international telecommunications association offering training, conferences, publications, and registration programs for cabling distribution designers, as well as commercial and residential installers.
The ratio of incorrectly transmitted bits to the total transmitted bits.
The permanent joining of metallic parts to form an electrically conductive path that will assure electrical continuity and the capacity to conduct safely any current likely to be imposed on it.
A conductor that interconnects the building's service equipment (power) ground to the telecommunications grounding system.
Multifiber cables where each optical fiber is further protected by an additional jacket and optional strength elements.
Method of disconnecting a circuit that has been electrically bridged to allow testing on either side of the circuit without disturbing cable terminations. Devices that provide break test access include disconnect blocks, bridge clips, plug-on protection modules, and plug-on patching devices.
The multiple appearances of the same cable pair or fiber at several distribution points. Also known as parallel connections.
A means of providing through connections between conductors or pairs that are terminated on connecting blocks. These through connections are commonly provided by means of individual metallic bridging clips or multiple bridging clips that are housed in a plastic insulator.
The transmission of multiple signals on a medium at the same time, sharing thee entire bandwidth of the medium (e.g., video signals multiplexed into channels with a bandwidth of 6MHz each).
The international term for intermediate cross-connect. A distributor in which the building backbone cable(s) terminates and at which connections to the campus backbone cable(s) may be made.
An assembly of two or more cables continuously bound together to form a single unit prior to installation (sometimes referred to as loomed, speed-wrap or whip cable constructions).
A linear configuration where all network devices are placed on a single length of cable. It requires one backbone cable to which all network devices are connected.
A combination of cables, wire, cords and connecting hardware used in the telecommunications infrastructure.
A covering over the optical fiber or conductor assembly that may include one or more metallic members, strength members, or jackets.
The international term for main cross-connect. The distributor from which the campus backbone cable emanates.
Balanced twisted-pair copper cable specifications characterized in a frequency range of 1 to 16 MHz.
Balanced twisted pair copper cable specifications characterized in a frequency range of 1 to 100MHz. This category specified transmission parameters that were not characterized by category 5 (e.g., power sum near-end crosstalk, return loss, equal level far-end crosstalk, and power sum equal level far-end crosstalk) and features more stringent near-end crosstalk than category 5.
Balance twisted-pair copper cable specifications characterized in a frequency range of 1 to 500 MHz. The augmentation from category 6 covers frequency range, insertion loss specifications, and alien crosstalk mitigation.
Balance twisted-pair copper cable specifications characterized in a frequency range of 1 to 600 MHz.
A common carrier switching center office (also called central office or public exchange) that is conveniently located in areas to serve subscriber homes and businesses.
The end-to-end transmission path connecting any two points at which application specific equipment is connected. Equipment and work area cables are included in the channel.
Application classes for cabling have been identified for the purpose of the ISO/IEC 11801 standard;
- Class A: cabling is characterized up to 100 kHz
- Class B: cabling is characterized up to 1 MHz
- Class C: cabling is characterized up to 16 MHz
- Class D: cabling is characterized up to 100 MHz
- Class E: cabling is characterized up to 250 MHz
- Class F: cabling is characterized up to 600 MHz
A centralized network contained in one device. The network is said to be collapsed and made to fit into a box. Individual networks are connected to this central device and can then communicate with one another.
A transmission scheme where voltages appear equal in magnitude and phase across a conductor pair with respect to ground. May also be referred to as longitudinal mode.
Type CMP communications plenum cable shall be listed as being suitable for use in ducts, plenums, and other spaces used for environmental air and shall also be listed as having adequate fire-resistant and low smoke-producing characteristics.
Type CMR communications riser cable shall be listed as being suitable for use in a vertical run in a shaft or from floor to floor and shall also be listed as having fir-resistant characteristics capable of preventing the carrying of fire from floor to floor.
The work space defined by the Occupational Safety and Health Administration as one a worker can enter in but that has limited or restrictive means of entry or exit and that is not designed for continuous occupancy (e.g., maintenance holes, splice pits, crawl spaces, and attics).
A location for interconnection between horizontal cables that extend from building pathways and horizontal cables that extend into work area pathways.
A facility enabling the termination of cables as well as their interconnection or cross-connection with other cabling or equipment. Also known as a distributor.
A connection scheme between cabling runs, subsystems and equipment using patch cords or jumpers that attach to connecting hardware on each end.
A standard unit for expressing transmission gain or loss as derived from a ratio of signal voltages or power.
The difference in propagation delay between the fastest and slowest pair in a cable or cabling system.
A point at which two services may interface and identify the division of responsibility.
A transmission scheme where voltages appear equal in magnitude and opposite in phase across a twisted-pair with respect to ground. May also be referred to as balanced mode.
A family os digital technologies designed to provide a variety of data transfer rates using different encoding and delivery methods.
The term used for the functions of a collection of components (e.g. patch panels, patch-cords) used to interconnect cables.
Systems that transmit or relay radio frequency signals (e.g., signals from cellular/personal communications system telephones, text pagers, wireless local area networks) within buildings, structures, tunnels, or other areas where wireless services cannot be otherwise provided.
The ability of a system to minimize radiated emissions and maximize immunity from external noise sources.
The interference in signal transmission or reception caused by the radiation of electrical and magnetic fields.
An organization that sets standards for interfaces to ensure compatibility between data communications equipment and data terminal equipment.
A standards organization that specializes in the electrical and functional characteristics of interface equipment. The organization sets standards for interfaces to ensure compatibility between data communications equipment and data terminal equipment.
An entrance to a building for both public and private network service cables (including antennae), including the entrance point at the building wall and continuing to the entrance room or space. Entrance facilities are often used to house electrical protection equipment and connecting hardware for the transition between outdoor and indoor cable.
An entrance to a building for both public and private network service cables (including antennae) beginning with the entrance point at the building wall and continuing to the entrance room or space.
The point of emergence of telecommunications conductors through an exterior wall, a concrete floor slab, or from a rigid metal conduit or intermediate metal conduit.
Crosstalk measured at the opposite end from which the disturbing signal is transmitted, normalized by the attenuation contribution of the cable or cabling.
A cable or cable assembly used to connect telecommunications equipment to horizontal or backbone cabling.
A centralized space for telecommunications equipment that serves the occupants of the building or multiple buildings in a campus environment. An equipment room is considered distinct from a telecommunications room because it is considered to be a building or campus serving (as opposed to floor serving) facility and because of the nature or complexity of the equipment that it contains.
A type of optical fiber connector identifiable by its round, screw-operated locking nut. It is usually metal. Its ruggedness leads it to be widely used in test equipment.
Crosstalk measured at the opposite end from which the disturbing signal is transmitted.
Operates at 100 megabits per second (Mb/s). Developed by the ANSI X3T9.5 committee. This is a token-passing, dual-ring architecture that provides redundancy using fiber optic cable with transmission up to 2 kilometers.
A communications scheme whereby electrical data is converted to light energy and transmitted through optical fibers.
A material, device, or assembly of parts installed in a cable pathway at a fire-rated wall or floor to prevent passage of flame, smoke or gases through the rated barrier (e.g., between cubicles or separated rooms or spaces).
The international term for horizontal cross-connect. The distributor used to connect between the horizontal cable and other cabling subsystems or equipment.
A conducting connection, whether intentional or accidental, between an electrical circuit (telecommunications) or equipment and earth, or to some conducting body that serves in place of the earth.
A distribution method in which individual cables are run directly from the horizontal cross-connect to each telecommunications outlet. This configuration is also known as star topology.
The cabling between and including the telecommunications outlet and the horizontal cross-connect.
A cross-connect of horizontal cabling to other cabling, e.g., horizontal, backbone, or equipment.
Equipment that serves as the centralized connection point for a network or portion thereof. Hubs are used for multiplexing, multi-port bridging functions, switching and test access. They can be either passive or active and are not considered to be part of the cabling infrastructure.
A collection of those telecommunications components, excluding equipment, that together provides the basic support for the distribution of all information within a building or campus.
The loss resulting from the insertion of a device in a transmission line, expressed as the reciprocal of the ratio of the signal power delivered to that part of the line following the device to the signal power delivered to that same part before insertion.
In an optical fiber system, the loss of optical power caused by inserting a component, such as a connector, coupler or splice, into a previously continuous optical path.
A wire connection device that penetrates the insulation of a copper wire when it is being inserted (punched-down) into a metal contact, allowing the electrical connection to be made.
A hub that performs bridging and routing functions in a collapsed backbone environment.
Telecommunications cable(s) that are part of the campus subsystem that connect one building to another.
A connection scheme that provides direct access to the cabling infrastructure and the ability to make cabling system changes using equipment cords.
The connection point between a backbone cable that extends from the main cross-connect (first-level backbone) and the backbone cable from the horizontal cross-connect (second-level backbone).
In a central office or customer premises, a frame that (a) cross connects the user cable media to individual user line circuits and (b) may serve as a distribution point for multipair cables from the main distribution frame (MDF) to individual cables connected to equipment in areas remote from these frames.
A prefabricated structure consisting of side rails connected at the bottom by transverse members (rungs) for supporting and routing cables or conductors within the structure.
An end-to-end transmission path provided by the cabling infrastructure. Cabling links include all cables and connecting hardware that comprise the horizontal or backbone subsystems. Equipment and work area cables are not included as part of a link.
A fixed wireless technology that operates in the 28GHz band and offers line-of-sight coverage over distances up to 3.0 km to 5.0 km (1.9 mi to 3.1 mi). It can deliver data and telephony services up to 80,000 customers from a single node.
A geographically limited data communications system for a specific user group consisting of a group of interconnected computers, sharing applications, data and peripheral devices such as printers and CD-ROM drives intended for the local transport of data, video, and voice.
The local regulated provider of public switched telecommunications services.
A measure (in dB) of the differential voltage induced on a conductor pair as a result of subjecting that pair to longitudinal voltage. LCL is considered to be a measure of circuit balance.
Medium Attachment Unit in reference to Ethernet A wiring concentrator used in Local Area Networks. A device that allows terminals, PCs, printers, and other devices to be connected in a star-based configuration to Token Ring or Ethernet LANs. MAU hardware can be either active or passive and is not considered to be part of the cabling infrastructure.
A cross-connect for first level backbone cables, entrance cables, and equipment cables.
A telecommunications outlet/connector for wire or cords as defined in the FCC Part 68 Subpart F. Modular jacks can have 4, 6 or 8 contact positions, but not all the positions need be equipped with contacts.
A telecommunications connector for wire or cords as defined in the FCC Part 68 Subpart F. Modular plugs can have 4, 6 or 8 contact positions, but not all the positions need be equipped with contacts.
A grouping in one location of several telecommunications/outlet connectors.
Category that includes apartments, townhouses, condominiums, and assisted living facilities. These facilities may be under a single roof or consist of multiple buildings ina a residential campus.
An optical fiber that will allow many bound modes to propagate. The fiber may be either a graded-index or step-index fiber. Multimode optical fibers have a much larger core than singlemode fibers. See also Optical Fiber Cable.
The undesired coupling of a signal from one pair of wires to another. Signal distortion as a result of signal coupling from one pair to another at various frequencies.
The point of interconnection between the local exchange carrier's telecommunication facilities and the telecommunications systems wiring and equipment as the end user's facility. This point shall be located on the subscriber side of the telephone company's protector or the equivalent thereof in cases where a protector is not required.
Circuitry in a device that provides the means to physically connect to a network.
Unit of measure of electrical resistance; one ohm is defined as the resistance that allows one ampere, the unit of electric current to flow when one volt is applied.
The mathematical relationship among electric current, resistance, and voltage. The voltage in volts is equal to the current in amperes multiplied by the resistance in ohms.
The cabling that distributes from the telecommunications closet to the open office area utilizing a consolidation point or multi-user telecommunications outlet assembly.
A seven-layer architecture developed by the International Oraganization fo Standardization that has served as a foundation for the development of many standards for network systems communications. The seven layers are physical, data link, network, transport, session, presentation, and application.
A transmission media using a thin filament of glass or plastic to transmit pulse light signals.
A fixed connecting device where the horizontal cable terminates. The telecommunications outlet provides the interface to the work area cabling. Sometimes referred to as a telecommunications outlet/connector.
Connecting hardware that typically provides means to connect horizontal or backbone cables to an arrangement of fixed connectors that may be accessed using patch cords or equipment cords to form cross-connections or interconnections.
A facility (i.e., conduit) for the placement and protection of telecommunications cables. Same as raceway or ducting.
A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.
A technology that describes a system to pass electrical power safely, along with data, on Ethernet cabling.
A private switching system usually serving an organization, such as a business, located on the customer's premises. It switches calls both inside a building or premises and outside to the telephone network, and can sometimes provide access to a computer from a data terminal.
The amount of time that passes between when a signal is transmitted and when it is received at the opposite end of a cable or cabling.
A method for securing wire to a quick clip in which the insulated wire is placed in the terminal groove and pushed down with a special tool. As the wire is seated, the terminal displaces the wire insulation to make an electrical connection. The punch down operation may also trim the wire as it terminates. Also called cut down.
A measure of vertical space in an equipment rack. One rack unit is equal to 45mm (1.75 in).
The disruption of radio frequency signal reception caused by any source which generates radio waves at the same frequency and along the same path as the desired wave.
A designation for individuals who demonstrate expertise in the design, integrations, and implementation of telecommunications transport systems and their related infrastructure components.
Noise or interference caused by impedance discontinuities along the transmission line at various frequencies. Return loss is expressed in decibels.
An optical fiber connector and adapter that provide for two strands of fiber in a surface area similar to an unshielded twisted-pair (RJ-style) plug and socket.
A low-level current that is of insufficient strength to trigger electrical surge protectors and, therefore, is able to pass through them undetected. These currents may result from contact between communications lines and AC power circuits or from power induction, and may cause equipment damage unless secondary protection is used.
A method of cabling each telecommunications outlet/connector directly to a cross-connect in a horizontal cabling subsystem.
A method of cabling each cross-connect (HC and IC) to the main cross-connect (MC) in a backbone cabling subsystem.
A rapid rise in current or voltage, usually followed by a fall back to a normal level. Also referred to as transient.
Any transmission, emission or reception of signs, signals, writings, images, sounds or information of any nature by cable, radio, visual, optical or other electromagnetic systems.
An organization that sets standards for cabling, pathways, spaces, grounding, bonding, administration, field testing and other aspects of the telecommunications industry.
An enclosed space for housing telecommunications equipment, cable terminations and cross-connect cabling used to serve work areas located on the same floor. The telecommunications closet is the typical location of the horizontal cross-connect and is considered distinct from an equipment room because it is considered to be a floor serving (as opposed to building or campus serving) facility.
A case or housing for telecommunications equipment, cable terminations, and cross-connect cabling.
A common point of connection for the telecommunications system and equipment bonding to ground, and located in the telecommunications room or equipment room.
Type of cable construction whereby each glass fiber is tightly buffered by a protective thermoplastic coating to a diameter of 900 microns. Increased buffering provides ease of handling and connectorization.
A transmission technique whereby several low-speed channels are combined into a single high-speed channel for transmission. Each low-speed channel is allocated a specific time position in the bit stream.
A device that sends a signal down a cable, then measures the magnitude and amount of time required for the reflection of that signal to return. TDRs are used to measure cable lengths as well as locate cable faults.
A telephony term used to describe the conductor of a pair that is grounded at the central office when the line is idle. This term was originally coined from its position as the first (tip) conductor of a tip-ring-sleeve switchboard plug.
The physical or logical layout of links and nodes in a network. These include star, ring and bus configurations.
A location in the horizontal cabling subsystem where flat under carpet cabling connects to round cabling.
A communication line between two switching systems. The term switching systems typically includes equipment in a central office (the telephone company) and PBXs. A tie trunk connects PBXs. Central office trunks connect a PBX to the switching system at the central office.
Trademark of 3COM Corporation. (See Twisted-pair Physical Media Dependent.)
A cable with multiple pairs of twisted insulated copper conductors bound in a single sheath.
A device that is inserted between a primary power source and the primary power input of equipment to be protected to eliminate the effects of transient anomalies or temporary outages.
A system in which voice signals are converted to packets and transmitted over a network using Transmission Control Protocol/Internet Protocol.
Developed to increase the information-carrying capacity of optical fiber transmission systems. This technique modulates a series of data streams using a different wavelength of light for each stream and simultaneously transports the wavelength over a single optical fiber.
The manufacturing process that physically binds the conductor insulation of the wire pairs of an unshielded twisted-pair cable.
The area where horizontal cabling is connected to the work area equipment by means of a telecommunication outlet. A station/desk which is served by a telecommunications outlet. Sometimes referred to as a work station.