ice bridge - The horizontal steel structure installed to support antenna cables running between a communications tower and shelter or cabinet housing wireless equipment. So named because the structure also shields the cables form ice that may fall from towers located in colder climates.

ice load - The weight factor calculated from the potential amount of ice that can build up on outside plant structures from storm conditions.

identifier (ID) - An item of information that links a specific element of the telecommunications infrastructure with its corresponding record. (TIA)

illuminator - A device that concentrates radio frequency energy at the focal point of a satellite dish. Also called a feed horn.

image rejection - The discarding of signal images by a receiver. Such images are produced due to mixing in the intermediate frequency section of the receiver, resulting in desired signals and undesired signal images.

imaging - The technologies associated with the conversion of documents into digital format,

immunity - The ability of a device, equipment, or system to perform without degradation in the presence of an electromagnetic disturbance.

impedance - The total opposition (resistance and reactance [capacitance and inductance]) that a circuit, cable, or component offers to the flow of alternating current at a given frequency. It is measured in ohms.

impedance discontinuity - An abrupt change in a cable's characteristic impedance. Impedance discontinuities can be caused by faulty connections, mismatched cable types, and untwisted sections on twisted-pair cable.

impedance match - A condition whereby the impedance of a particular circuit, cable or component is the same as the impedance of the circuit, cable or device to which it is connected.

impulse noise - Discrete noise spikes having random amplitude and spectral content.

incidental radiators - A device that generates radio frequency energy during operations although it has not been intentionally designed to do so.

independent basic service set (IBSS) - A group of stations in a wireless LAN that communicate directly with each other (without the use of a central access point). This type of network is also known as an ad-hoc network.

index of refraction (IOR) - The ratio of the velocity of light in a vacuum to the velocity of a signal in a given material. Also called refractive index.

index sheet - A part of the drawing set, maintained by the architect and providing general information, including the site address, owner's name, and architect's name.

index-matching gel - A material used in optical fiber connections or splices that has a refractive index close to that of the optical fiber core; used to reduce reflections from the residual air gap.

inductance - A condition that opposes the flow of current while causing a voltage phase shift in +90 degrees.

induction - Phenomenon of a voltage, magnetic field or electrostatic charge being produced in an object from the source of such fields.

inductive amplifier - Test device used to detect a signal placed on a cable for the purpose of tracing and identification. Also called a wand or probe.

inductive coordination - The cooperative effort of telecommunications and power company personnel in the engineering and application of measures and devices to ensure compatibility of operation between both systems for noise reduction and protection.

inductive coupling - The transfer of electromagnetic energy from one circuit to another.

industrial, scientific, and medical (ISM) - Unlicensed frequency band in the 2.4 GHz range.

industry negative file (INF) - A database consisting of fraudulently created mobile identification number/electronic serial number used to screen false cellular access.

information transport systems (ITS) - industry Pathways, spaces, cabling systems, wireless systems, and infrastructure that support the transportation of data and data signaling between communication, data processing, data display, or information gathering devices.

informational submittals - Document information the architect or engineer requires to verify performance and quality control of project components, but do not require approval. They are also used as verification and certification that the installed work or portion of the work meets the specified requirements. (CSI) infrared (IR) The electromagnetic spectrum having wavelengths between 750 nm and 1 mm (7.5o10-' m - 1. 10-3 m) or between 30 and 40,000 microinches (3o10-$ in - 4o10-2 in).

infrared conversion card - Allows a cabling installer to visually detect an infrared signal when that signal is directed at the card's phosphorus material.

infrastructure (telecommunications) - 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. (TIA)

ingress - 1. An electrical characteristic associated with externally generated noise induced into cable facilities. 2. A point of entry for a building or property.

initiating device circuit (IDC) - A circuit to which automatic or manual initiating devices are connected where the signal received does not identify the individual device operated.

in-line splice - A splice in which cable enters one end cap and, after splicing the cable, exits the other end cap of the closure.

innerduct - A nonmetallic raceway, usually circular, placed within a larger pathway. (TIA)

input impedance - The ratio of the voltage at the sending end of the line to the current in the line at the sending end.

inrush (amperes) - The current that a device requires during its initial power-up.

insert - An opening into the distribution duct or cell from which wires or cables emerge. (TIA) See also insert, afterset and insert, preset.

insert afterset - An insert installed after the installation of the concrete floor slab or other flooring material. (TIA) See also insert; contrast with insert, preset.

insert, preset - An insert installed prior to the installation of the concrete floor stab or other flooring material. (TIA) See also insert; contrast with insert, afterset.

insertion card - A card that must be inserted into a card reader for the reader to retrieve the information stored on the card.

insertion loss deviation - The difference between the actual insertion loss as measured on a permanent link or channel and the insertion loss as determined by adding the component losses. (TIA)

insertion loss - The signal loss resulting from the insertion of a component, or link, or channel, between a transmitter and receiver (often referred to as attenuation). (TIA) See also attenuation.

instant messaging - Text-only real-time conferencing. Also called chat.

insulating gap - A capacitor installed on the field side of an insulating joint.

insulating joint - An opening in a cable sheath or down guy where continuity is deliberately interrupted to prevent the flow of currents.

insulation - The dielectric material that physically separates wires and prevents conduction between them.

insulation displacement contact (IDC) - A type of wire termination in which the insulation that is surrounding a conductor is displaced at the connection point without physically stripping the insulation from the conductor and consequently makes a gas-tight connection to the conductor.

integrated digital enhanced network (iDEN°) - A wireless technology that provides digital cellular telephone, two-way radio, alphanumeric pager, and data/fax modem services in a single network.

integrated services digital network (ISDN) - A fully digital communications facility designed to provide transparent endto-end transmission of voice, data, audio/ video, and still images across the public switched telephone network. Different versions exist for North America and Europe.

integration - The seamless gathering of many similar and dissimilar systems as if they were one system. In relation to electronic safety and security, integration may involve the interconnection or convergence of components of these systems as well as other building, vehicle, or communications systems for purposes of data collection, monitoring, management, and control. See also convergence.

integrity services - Network processes that provide the assurance that messages are authentic and unaltered.

intelligent device (ID) - Addressable device used to monitor and control functions in a building automation system network.

intelligibility - For voice communications, the capability of being understood by the intended audience. Intelligibility does not imply the recognition of a particular voice. It cannot be measured with instrumentation but may be electronically simulated and measured utilizing an indexing method.

intentional radiator - A device designed to generate and emit radio frequency energy during operations using radiation or induction.

inter-access point protocol (IAPP) - A protocol developed by the IEEE to enable interoperability between access points manufactured by different vendors. Adopted as IEEE 802.11f in 2003.

interbuilding (campus) backbone - A backbone network providing communications between more than one building.

interbuilding backbone cable - 1. Cable that runs between buildings in a campus environment. 2. Outside plant cabling.

interbuilding backbone cable interconnection - A connection scheme that employs connecting hardware for the direct connection of a cable to another cable without a patch cord or jumper, or single-port equipment connections to horizontal or backbone cabling.

interbuilding backbone pathway - Provides the means to connect main terminal spaces in different buildings.

interbuilding backbone - A pathway and/or cable facility from the entrance room/space provided for interconnecting to other buildings, as in a campus environment.

intercom/paging system - A communications device used for either one-way or two-way voice broadcasts.

interconnect - See interconnection

interconnection - 1. A connection scheme that employs connecting hardware for the direct connection of a cable to another cable without a patch cord or jumper. 2. A type of connection in which singleport equipment connections (e.g., 4-pair and optical fiber connectors) attach to horizontal or backbone cabling by means of patch cord or jumper.

interface - 1. A shared boundary. A physical point of demarcation between two devices or systems where electrical signals, connectors, and timing are defined. 2. The procedures, protocols, and codes that allow two devices to interact for the purpose of exchanging information.

interference - Undesirable signals on a device, equipment, or system. See also electromagnetic interference.

interlock - A system of multiple doors that control interaction. No door can be unlocked unless all other doors are secure and locked. Also known as light or air trap, mantrap, and sally port.

intermateability - See interoperability.

intermediate cross-connect (IC) [building distributor (BD)] - The connection point between a backbone cable that extends from the main cross-connect (campus distributor [first-level backbone]) and the backbone cable from the horizontal cross-connect (floor distributor [second-level backbone]). Building distributor is the international equivalent term for intermediate cross-connect.

intermediate distribution frame (IDF) - Refer to horizontal cross-connect (floor distributor) and intermediate cross-connect (building distributor).

intermediate frequency (IF) - The frequency to which a carrier frequency is shifted as an intermediate step in signal transmission or reception.

intermediate network - A network used to connect two or more networks. See also internetwork.

intermittent duty solenoid - A currentcarrying coil of wire that acts like a magnet when a current passes through it that is designed to be energized for short periods of time. Continuous operation maydamage an intermittent duty solenoid.

intermodulation interference (IMI) Also known as intermod. - Spurious signals that disrupt wireless communication and are the result of two or more strong signals passing through a nonlinear device and multiplying by each other. Most commonly, intermod is generated within a receiver's amplifying stages, especially when the receiving antenna is located near one or more powerful transmitters. Intermodulation products also can be produced in a transmitter when the signal from one transmitter unintentionally enters into another transmitter. Poor cable connections or connections between dissimilar metals can be a source of intermod.

Internet acceleration - A term used to describe a content acceleration appliance that is used to cache content requested by local users at a site. Normally such content is retrieved from remote servers over telecommunications circuits. Also called forward proxy. See also Web site acceleration.

Internet access management - See surf control.

Internet protocol (IP) - The Open Systems Interconnection Reference Model Layer 3 (Network layer) protocol most commonly used for internetworking. Required for communications over the Internet.

Internet protocol (IP) address - The Open Systems Interconnection Reference Model Layer 3 (Network layer) address assigned to devices using the IP. Also called an Internet address.

Internet protocol security (IPsec) - A security protocol used for data encryption when communicating over an IPbased network.

internetwork - The connection of two or more networks.

internetworking - Enables communications between devices attached to different networks

interoperability - The ability of systems, units, or forces to provide services, to accept services from other systems, units, or forces, and to use the services so exchanged to enable them to operate effectively together. (ATIS)

interstitial space - A small or narrow space located above or below the occupant's space on each floor that is used for routing building services (e.g., lighting; heating, ventilating, and air conditioning; power; telecommunications; plumbing).

intrabuilding backbone cable - Cable that runs between telecommunications rooms inside a building. Can be vertical or horizontal in physical orientation.

intrabuilding backbone pathway - Provides the means to connect main terminal space and telecommunications rooms within a building.

intrabuilding telecommunications backbone - A pathway or cable facility for interconnecting telecommunications service entrance rooms, equipment rooms, and telecommunications rooms within a building.

intranet - A collection of users/servers designed to provide content, via methods similar to the World Wide Web, to a limited group of users, defined by security restrictions, on an internal network.

intrusion detection - The process of detecting and tracking actual or attempted unauthorized access to a network or a protected device.

intumescent - Ability to enlarge or swell under the influence of heat.

intumescent firestop - A firestopping material that expands under the influence of heat. (TIA)

inverse multiplexing - The process of taking a large digital message and breaking it into smaller data streams for transmission on multiple smaller bandwidth media. The opposite end reverses the process and reassembles the original message.

ionosphere - A section of the atmosphere that extends from about 70 km to 500 km (43.5 mi to 311 mi) in altitude, in which ions and free electrons exist in sufficient quantities to reflect and/or refract electromagnetic waves.

isoceraunic map - A geographical map of a wide area (e.g., United States) with continuous lines connecting points of equal thunderstorm-day activity that provides a relative comparison of the thunderstorm activity in one area to that of another area.

isochronous - 1. A property of signals where the signals are dependent on some uniform timing or carry their own embedded timing as part of the signal. 2. A property of electronic systems where all devices in a network derive their timing signal directly or indirectly from the same primary reference clock.

isolation gap - A procedure that isolates the building ground from the outside plant ground by removing the armor shield from the entrance cable for a short distance and inserting a capacitor to connect from one side of the armor shield to the other side. This may be accomplished at a splice point or in the entrance cable sheath itself.

isolation transformer - A transformer with high galvanic insulation used to break ground loops at low frequency in communications systems operating over copper cables.

isolator, radio frequency - A passive device used to control the propagation of a radio frequency signal by allowing the signal to pass in one direction while providing high isolation to reflected energy in the reverse direction.

isotropic radiator - A theoretical model antenna that radiates power with identical and constant intensity in all directions from a point source. Used as a reference standard to compare the radiation properties of all other types of antennas.

issuer - The person or company that issues a request for quote or request for proposal.