A - The Global System for Mobile Communications interface between the basic service set and network substation.

A3 - A stream cipher used for authentication in the Global System for Mobile Communications authentication center database subsystem.

A5 - A stream cipher used for encryption of transmissions in the Global System for Mobile Communications authentication center database subsystem.

A-bis - The Global System for Mobile Communications interface used when the base station controller is not collocated with the base transceiver station.

ablative - The development of a hard char that resists the erosion of fire and flames; a characteristic of a firestop when exposed to fire.

above finished floor (AFF) - Standard mounting height or vertical distance (e.g., 48 inch AFF) 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.

absorption 1. A phenomenon causing attenuation of a radio signal passing through a medium. It occurs when gaseous molecules or suspended water particles in the atmosphere absorb the signal energy and convert it into heat due to molecular resonance. 2. In the transmission of electrical, electromagnetic, or acoustic signals, the conversion of the transmitted energy into another form, usually thermal. Absorption is one cause of signal attenuation.

accelerator - A chemical agent used to hasten a chemical reaction for setting permanent bonds on epoxy glues.

acceptance angle The half-angle of the cone within which incident light is totally internally reflected by the optical fiber core/cladding boundary. The light within this cone is coupled into reflected modes of the optical fiber.

acceptance plan - A facilitating agreement between parties (e.g., contractor and client or client representative) that defines satisfactory completion of a project task or complete project. It may include items on which the client's acceptance is dependent (e.g., delivery of as-built drawings, test certification).

acceptance test - A test or set of tests performed to demonstrate satisfactory completion of a predetermined task or group of tasks on which acceptance is dependent.

access - The process of connecting to a network.

access code - The numeric or alphanumeric characters that, when -entered correctly, authorize access into a secure area.

access control (AC) 1. The manner in which devices are granted or denied access to the resource in cases where two or more devices simultaneously attempt to use a shared resource (e.g., telecommunications circuit between two sites, specific printer). 2. An identification device assigned to an individual to give that individual access rights to an access control system.

access control (AC) card - An identification card with encoded information that, when presented to a card reader, identifies the cardholder to the access control system, allowing that system to determine the cardholder's entrance and exit rights.

access controller - A component of an electronic access control system whose primary function is to consolidate field-mounted peripheral devices and communicate bidirectionally between the system's headend software and fieldmounted peripheral devices.

access control list (ACL) - The database that keeps track of and controls access to network services or physical entry to an area through assigned privileges for users and groups. Also called authorization profile.

access control mechanism - The way devices on a LAN are granted or denied access to the network.

access control system - An interconnected set of controllers, managing the entrance and exit of people through secure areas.

access floor - 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.

access group - A superset of information, including time zones and secured doors, that is applied toward holders. This information defines at what time of day and through which doors cardholders are granted access.

access level matrix An access control system reference that is specific to each system for which it is being utilized. The purpose of the document is to provide a hierarchy of rights and privileges for different user groups and their associated authorized zones.

access line - A telecommunications circuit provided by a service provider at the demarcation point.

access parameter - The programmed information that defines the conditions that must be met to grant access to a secure area.

access point (AP) 1. The point of entry into a secure area. 2. A stand-alone hardware device or a computer wireless adaptor with software that acts as a wireless communication hub for users of wireless devices to connect with each other and to bridge those devices to the cabled portion of the network.

access protocol - The set of procedures that enables a user to obtain services from a network (e.g., carrier sense multiple access with collision detection and token passing for LANs). Also called media access control protocol.

access provider (AP) 1. A company (e.g., telephone company) that provides a circuit path between a service provider (SP) and the client user. An AP also can be the SP. 2. The operator of any facility that is used to convey telecommunications signals to and from a customer premises. See also service provider (SP).

accounting - Tracking of all authentication requests and resource access attempts (successful or failed) for review by network administrators and auditors.

accounting management - The tracking, billing, and cost allocation for network resource use.

acknowledgment (ACK) - A frame used in IEEE 802.11 to acknowledge that an error-free, data-free, frame has been received.

acoustical coupling Describes how acoustical vibrations in one media resonate into another media without a direct connection.

acrylate A coating applied during the optical fiber manufacturing process to provide physical and environmental protection for the optical fiber.

active card A type of access card that is dependent upon a card reader to provide the power necessary to allow the card to transmit its data.

active circuit Any circuit connected to an energized system.

active cross-connect A facility enabling the termination of cable elements and their interconnection or cross-connection by electronic means.

active equipment Energized equipment used for receiving or transmitting analog or digital signals (e.g., switches, hubs, routers, private branch exchanges).

active hub A powered device that can amplify, retime, or regenerate incoming signals to minimize errors and message corruption. See also hub and passive hub.

active monitor A device that monitors the operation of the ring on a token ring LAN.

active tracking A method of compensation for alignment variations in antennas.

adapter A device that enables any or all of the following: o Different sizes or types of plugs to mate with one another or to fit into a telecommunications outlet, o The rearrangement of leads, o Large cables with numerous conductors to fan out into smaller groups of conductors, and o Interconnection between cables. (TIA)

adapter - optical fiber duplex A mechanical device designed to align and join two duplex optical fiber connectors (plugs) to form an optical duplex connection. (TIA)

addendum A document used to provide additional requirements and recommendations to a published document (e.g., standards, contracts). When published, an addendum effectively becomes part of the document that it supports.

address 1. A unique identification code assigned to a network device, used to associate a message with its source and destination. See device address, medium access control (MAC) address, and network address. 2. A unique location in a computer's memory or other electronic storage medium. See medium access control (MAC) address and network address.

address resolution - A process used to associate network addresses with media access control addresses.

ad hoc network A peer-to-peer network characterized by communication between nodes without the need for an infrastructure. Also called independent basic service set.

adjacent channel discrimination A measure of the ability of a receiver to successfully receive a signal in a wanted frequency channel in the presence of unwanted signals on adjacent frequency channels, which are being picked up by the antenna.

adjacent channel interference Interference caused by the residual energy of a neighboring radio frequency channel overlapping onto the desired channel.

adjacent channel rejection The ability of a receiver to reject interference caused by a transmitter operating on an adjacent channel.

administration 1. The methodology defining the documentation requirements of a cabling system and its containment, the labeling of functional elements, and the process by which moves, additions, and changes are recorded. (ISO) See also labeling system. 2. See network administration.

advanced encryption standard (AES) A National Institute of Standards and Technology secret key encryption using 128 to 256 bit keys.

aerial-buried plant A general term for all outside plant cable runs made up of both aerial and direct-buried cables. aerial cable Telecommunications cable installed on aerial supporting structures (e.g., poles, sides of buildings, other structures). (TIA)

aerial entrance An entrance facility where the cables providing service to a building are placed overhead and the entry point is located above the ground level.

aerial plant An overhead infrastructure to provide telecommunications services between facilities.

afterset insert See insert, afterset.

agent An application to collect information about a device and make that information available to a network management system. Agents operate in managed devices on the network (e.g., hubs, switches, servers, stations).

air bottle Portable compressed air or gas source.

air feeder pipe An underground pipe that parallels cable runs and is used to supply air for pressurized cables.

air handling unit (AHU) Monitors and controls the air by volume, temperature, and humidity before being released into a specified building area. Typically, an AHU consists of a fan, hot and/or cold coils, and supply/return ducts and dampers. The AHU mixes indoor/outdoor air and passes the mixture of air through the coils.

air terminal A strike termination device that is a point receptor for attachment of flashes to the lightning protection system and is listed for the purpose. Typical air terminals are formed of a tube or solid rod. Also called a lightning rod.

alarm indicator A device or a combination of devices (e.g., bell, lamp, strobe, horn, gong, buzzer) that responds to a signal from an alarm sensor and indicates a fault or emergency condition.

alien crosstalk A measure of the unwanted signal coupling between adjacent cabling or components.

alien far-end crosstalk (AFEXT) A measure of the unwanted signal coupling between pairs in adjacent cabling from a transmitter at the near end into a pair measured at the far end.

alien near-end crosstalk (ANEXT) loss A measure of the unwanted signal coupling between adjacent cabling from transmitters at the near end into a pair measured at the near end.

all dielectric self-support (ADSS) A type of aerial optical fiber cable that is nonconductive/nonmetalic and requires no messenger strand for installation.

all-threaded-rod (ATR) A straight section of fully threaded round rod stock. Also called a threaded rod.

alternate entrance A supplementary entrance facility into a building using a different routing to provide diversity of service and for assurance of service continuity. (TIA)

alternate route A secondary communications path used to reach a destination. See also diverse route.

alternating current (ac) Electric current that alternates periodically (usually sinusoidal) in magnitude ahd direction. Contrast with direct current (dc).

alternating current equipment ground (ACEG) A conductor installed from the equipment grounding busbar inside an electrical panel to a telecommunications grounding busbar or telecommunications main grounding busbar.

ambient sound level The level of acoustic noise existing at a given location (e.g., room, area). Ambient noise level is measured, in accordance with NFPA 72®, National Fire Alarm Code', with a sound level meter as the root mean square, Aweighted, sound pressure level measured over the period of time that any person is present or a 24-hour period, whichever time period is the lesser.

American National Standards Institute (ANSI) cutout A standard or stock cutout furnished on doors and frames from the door or frame manufacturer.

American wire gauge (AWG) 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 of drawing processes applied to a given wire.

ampacity The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.

ampere (A, amp) A unit of measurement of electric current. One ampere is equal to the current produced by one volt flowing through a resistance of one ohm.

amplifier A device that increases the power level (amplitude) of an analog signal (waveform). Amplifiers boost the power in its assigned frequency range, including the intended signal and any induced noise.

amplitude The maximum absolute value reached by a voltage or current waveform.

amplitude modulation (AM) Modulation in which the amplitude of a carrier wave is varied in accordance with some characteristic of the modulating signal.

analog See analog signal.

analog input (AI) A device (e.g., temperature sensor) that sends a continuously variable signal to a building automation system controller.

analog output (AO) A device (e.g., damper actuator) that receives a continuously variable signal from a building automation system controller.

analog signal An analog signal is a continuous function of time. Contrast with digital signal.

anchor 1. A fastening device. 2. In an outside plant environment, a device made up of a single plate or series of flat plates and combined with a rod having a connecting eye.

anchor rod The portion of an anchor assembly that extends above the anchor plate below ground level to a point above ground level.

angle polished connector (APC) An optical fiber connector polished at an angle of 8 to 10 degrees to the fiber axis (the critical angle) to reduce the backreflection of the signal. Some high-performance singlemode systems (e.g., high bandwidth analog video systems) require a very low level of back-reflection (-55 dB or better) to perform correctly.

annular space A space between penetrating item and inside wall of penetration.

annunciator A unit containing one or more indicator lamps, alphanumeric displays, or other equivalent means in which each indication provides status information about a circuit, condition, or location.

antenna A conductive structure specifically designed to couple or radiate electromagnetic energy. In radio frequency systems, the antenna may be used to both transmit and receive electromagnetic energy.

antenna array (including panel) An antenna made up of a number of elements arranged in a periodic pattern including an active or driven element, a reflector, and a director. Array antennas may be narrowband or broadband, and are used in all frequency bands.

antenna entrance A pathway facility from the antenna to the associated equipment. (TfA)

antenna gain 1. A term used to describe the capability of an antenna to direct signal or reshape energy in a particular direction. 2. The ratio of the power required at the input of a loss-free reference antenna (usually an isotropic radiator or dipole) to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength at the same distance. Antenna gain is usually expressed in decibels relative to an isotropic radiator (dBi) (isotropic reference).

antipassback A method for providing one card one-way access into and out of a secure area. It prevents someone from using a card to enter a secure area and then passing that card back to another to enter that same area.

aperture size 1. The effective capture area of an antenna. The term is commonly used in connection with microwave horn antennas and waveguides. 2. The physical size of the opening in a camera lens, expressed as F-stops.

apparatus A finished combina6on of devices (or equipment) intended to be placed on the market as a single commercial unit.

apparatus closet See telecommunications room.

AppIeTalk A proprietary network protocol stack developed by Apple Computer that allows LAN functionality such as file and print sharing. Its primary features are autoconfiguration and ease of use.

application address An address used to uniquely identify each software process running on a network device. See also medium access control (MAC) address and network address.

Application layer The Open Systems Interconnection Reference Model layer responsible for providing mechanisms that enable software applications on different systems to use the services of a network to exchange information. Also called Layer 7.

application sharing The process of running a software program on one station and allowing users at other stations to see and optionally control the application over the network.

application software Software used to perform a specific task (e.g.,.word processing, spreadsheet analysis, database management).

application specific cabling Cabling installed to meet the requirements of a specific transmission system or application.

approved ground A grounding (earthing) source approved for use by the authority having jurisdiction. See also earth ground and ground.

aramid A material with exceptional tensile strength and coefficient of thermal expansion near that of glass. Widely used as a strength member in optical fiber cables. See aramid yarn.

aramid yarn A strength element used in optical fiber cable to provide support and additional protection of the fiber bundles. See also aramid.

arbitration 1. A method of negotiation used in resolving disputes between parties. 2. The process of determining which requesting device will gain access to a resource. (IEEE)

arbitration loop (AL) A link that connects all disk drive nodes together and manages with a token acquisition protocol.

architectural assemblies Walls, partitions, or other barriers that are not load bearing. (TIA)

architectural drawing A two-dimensional graphical representation of a building, space, or object prepared with adequate detail to convey design information in a manner to serve as a guide for construction thereof.

architectural, mechanical, electrical, structural (AMES) Drawings or blueprints that include AMES designs.

architectural structures Walls, floors, floor/ceilings, and roof/ceilings that are load bearing. (TIA)

archive Collection and storage of data, records, or information.

armoring Method used for protecting cables against crush, impact, rodents, etc. Can be achieved through the use of corrugated steel, fiber-reinforced polymer rods, steel wire, glass yarns, or other suitable materials under or over the outer sheath of the cable.

arrester A device placed from phase to ground whose nonlinear impedance characteristics provide a path for high-amplitude transients. (Heneveld's Pocket Guide to Residential Technology Terms and Definitions)

asbestos Fibrous mineral substance used in buildings as insulation between the mid-1940s and 1978 and later found to be carcinogenic (cancer causing).

as-built The documentation of measurements, location, and quantities of material work performed. May be in the form of marked up documents or other work order forms.

aspirator An apparatus for producing suction: moving or collecting materials by suction.

asymmetric digital subscriber line (ADSL) Adigital service designed to provide high data transfer rates over traditional telephone cable. Asymmetric refers to different speeds for uplink and downlink traffic. See also digital subscriber line (xDSL).

asymmetric full-duplex A transmission process that allows different sending and receiving transfer rates to coexist on the same path for Ethemet video-on-demand.

asymmetric key cryptography See public key encryption.

asynchronous communication See asynchronous signaling.

asynchronous signaling A form of signaling in which each data character is coded as a string of bits. The bits are separated by start character and stop character bits. See also asynchronous transmission, isochronous communication, synchronous communication, and synchronous transmission.

asynchronous transfer mode (ATM) A high-speed network switching protocol that utilizes fixed-length (53 byte) packets, called cells, to carry all types of traffic (e.g., voice, data, still image, audio/video).

asynchronous transmission See asynchronous signaling.

attached resources computing network (ARCnet) A 2.5 Mbls or 20 Mb/s logical token-bus network configured in either a physical star or daisy chain.

attachment unit interface (AUI) The name used by the IEEE 802.3 standard for the cable that connects the media attachment unit to a 10 Mbls network device. This cable is equipped with a 15-pin connector. The corresponding 15-pin connector on an attaching device often is called an AUI connector.

attenuation The decrease in magnitude or the power loss of a signal that propagates between points, expressed in dB as the ratio of received signal to transmitted signal level. See also insertion loss.

attenuation-to-crosstalk ratio (ACR) The ratio obtained by subtracting insertion loss (attenuation [dB]) from near-end crosstalk (dB). ACR is normally stated at a given frequency. See also bit error rate (BER) and signal-to-noise ratio (SNR).

attenuator A device used to reduce the amplitude of an electrical signal without introducing appreciable distortion. audible signal Sound made by one or more audible notification appliances (e.g., bells, horns, speakers) in the response to the operation of any manual or automatic electronic device.

audio Something that is heard or having to do with something that is heard as sounds in the audio frequency range, which the average human can detect; in audio/video, having primarily to do with the process of reproducing sounds through a system of electronic components.

audio frequency (AF) The band of frequencies (approximately 20 Hz to 20 kHz) corresponding to a normally audible sound wave. Contrast with voice frequency (VF).

audit trail A sequential record that accounts for all the activities of an access control system. This record allows for the analysis of events over a given time period.

aught Colloquial term for numerical symbol "0" that is used in the numbering scheme for conductors larger than 0 AWG [8.3 mm (0.33 in)] (e.g., 2/0 AWG [13.41 mm (0.528 in)] is two aught).

augmented category 6 See category 6, augmented.

aural ear protectors Resemble ear muffs; available in passive or active models. See ear protector.

authentication A security mechanism that confirms the identity of a user accessing the network.

authentication, authorization, and accounting (AAA) Three network administration activities that are often tied together in a single network protocol/server (e.g., Internet Engineering Task Force remote authentication dial-in user service standard). See also the individual entries for authentication, authorization, and accounting.

authority having jurisdiction (AHJ) The entities responsible for interpretation and enforcement of local building and electrical codes.

authorization The process of establishing and enforcing the network activities that are permitted for a given user.

authorization level A security rating that must be met before access to a secure area can be granted.

authorization profile See access control list (ACL).

authorized passage device (authorized egress device) A device that, when activated, allows authorized persons to enter or exit monitored and controlled openings without triggering an alarm. The authorized passage device may be a keyed switch, card reader, or digital code reader.

automatic call distributor (ACD) A voice switching device that provides highly specialized call handling capabilities normally associated with call centers and other high-volume applications. Typically has extensive automated attendant functionality and computer-telephony integration features.

automatic gain control (AGC) A process or means by which gain is automatically adjusted in a specified manner as a function of a specified parameter (e.g., received signal level).

autonegotiation (AUTONEG) A feature that determines link options and optimal settings for a given connection. When AUTONEG is enabled, a network interface card can determine the capabilities of the device at the far end of the link and select the best mode of operation.

autorange Automatic ranging by an optical time domain reflectometer.

autosetup A capability where the test instrument automatically sets the testing parameters to appropriate levels for the component under test. Also called autoranging or automode.

autotest A function used by field test instruments to run all the required tests in a sequential manner without operator intervention.

auxiliary disconnect See auxiliary disconnect outlet (ADO) and auxiliary disconnect outlet (ADO) cable.

auxiliary disconnect outlet (ADO) 1. An extension of a demarcation point from a common owner's space into a tenant's individual space. 2. A device usually located within the tenant or living unit used to terminate the ADO or backbone cable (TIA).

auxiliary disconnect outlet (ADO) cable 1. The cable that extends the demarcation point in a common owner's space to a tenant's individual space. 2. In residential applications, the cable from the auxiliary telecommunications disconnect outlet/connector or the distribution device in a customer's premises to the backbone facility or the point of demarcation. (TIA).

availability A measure of network response time or freedom from operating failure (downtime) during a given period of time.

availability attack The disruption of network operations by maliciously generating enough traffic to cause congestion and thereby rendering the network unavailable to intended users.

average power (PA) Sustainable or usable portion of electrical energy in an alternating current over some amount of time. For sinusoidal signals, it is the peak power (PP) multiplied by .707 (e.g., 100 watts of PP is approximately equal to 71 watts of PA). See also power and peak power.