I - Symbol used to designate current. From the French word for current intensity (intensite du courant).
I/O (input/output) - The process of transmitting data to and from the processor and its peripherals.
I2R - Formula for power in watts, where l=current in amperes, R=resistance in ohms.
I2R - Formula for power in watts, where l = current in amperes, R = resistance in ohms. See WATT.
IACS - International Annealed Copper Standard for copper used in electrical conductors. 100 percent conductivity at 20°C is 0.017241 ohm-mm2/m.
IAD - Integrated access device.
IC - Intermediate cross connect.
ICEA (Insulated Cable Engineers Association) - The association of cable manufacturing engineers who make nationally recognized specifications and tests for cables. Formerly IPCEA.
IDC - Insulation displacement connector.
IDE - Integrated drive electronics also known as ATA (advanced technology attachment).
IDF - Intermediate distribution frame.
IDMS (identity management system) - A system that manages the identities and privileges of computer systems and people. Can be used in conjunction with both physical and IT access control.
IDS (intrusion detection system) - A system that monitors network traffic and responds with an alarm when it detects port scanning, an unauthorized access attempt, a denial-of-service attack or other forms of attack on the network.
IEC - International Electrotechnical Commission.
IEEE (Institute of Electrical and Electronic Engineers) - An international professional society that issues its own standards and is a member of ANSI and ISQ.
IEEE 10BASE2 network - A network conforming to the IEEE 802.3 local area network standard. The network is capable of carrying information at rates up to 10 Mbps over distances up to 185 meters; also called thin net.
IEEE 10BASE5 - A network conforming to the 8023 local area network standard. The network is capable of carrying 10 Mbps of data over coax cable for distances up to 500 meters.
IEEE 10BROAD36 - 10 million bits per second over broadband coaxial cable with node-to-node coverage of 3,600 meters. The IEEE 802.3 specification for running Ethernet on broadband.
IEEE 488 (Institute of Electrical And Electronic Engineers - 488) - An IEEE standard parallel interface bus consisting of eight bi-directional data lines, eight control lines and eight signal grounds, which provide connections to an IEEE-488 device.
IEEE 488 241C gen. interface bus cable assembly - Meets the requirements of IEEE 488 standard for cable interface of up to 15 programmable instruments in a BUS-connected system. Dual-sided connector can terminate into a star or daisy chain.
IEEE 802 - Standards for the interconnection of local networking computers equipment. The IEEE-802 standard deals with the physical link layers of the ISO Reference Model for OSI.
IEEE 802.1 - The standard that defines the network layer of the OSI Model for LANs. IEEE 802.1d defines the spanning tree protocol (STP) used by bridges to detect and break any loops found in an Ethernet network.
IEEE 802.11 - Wireless LAN standard.
IEEE 802.15 - Wireless PAN. (Bluetooth)
IEEE 802.2 - A subcommittee responsible for defining the upper half of the data link layer, known as the LLC or logical link control.
IEEE 802.3 - An IEEE standard describing the physical and data link layers of a local area network based on bus topology and CSMA/CD. (Ethernet)
IEEE 802.3af - Data terminal equipment (DTE) power delivery standard. Commonly referred to as Power over Ethernet (PoE).
IEEE 802.4 - A physical layer standard specifying a LAN with a token-passing access method on a bus topology. Used with manufacturing automation protocol LANs.
IEEE 802.5 - A physical layer standard specifying a LAN with a token-passing access method on a ring topology. Used by IBM’s token ring hardware.
IEEE 802.6 - The IEEE project 802 LAN Standards for Empty Slot Ring. A ring LAN in which a free packet circulates past, or more precisely, through every station; a bit in the packet’s header indicates whether it contains any messages (if it contains messages, it also contains source and destination addresses).
IEEE 802.7 - A proposed physical layer standard specifying a LAN using both 802.3 and 802.4 standards.
IEEE 802.8 - The IEEE Project 802 committee responsible for defining standards for optical fiber LANs.
IEEE 802.g - A committee looking into aspects of ISDN type voice and data integration across IEEE 802.3 and 802.4 LANs. As yet, the IEEE 802.9 committee has made “proposals,” but has not published any “standards.”
IEEE-488 - An IEEE standard for a parallel interface bus consisting of eight bidirectional data lines, eight control lines and eight signal grounds, which provides for connection to an IEEE-488 device.
IETF - Internet Engineering Task Force.
IF - Intermediate frequency.
IGMP (Internet Gateway Multicast Protocol) - A standard IP protocol. When used in MAPs it is the signaling mechanism used with multicasting of video. The set-top box uses IGMP to insert or remove a subscriber from a video stream (IGMP multicast filtering).
Image size - Reference to the size of an image formed by the lens onto the camera pickup device. The current standards are 1 in., 2/3 in., 1/2 in. and 1/3 in. measured diagonally.
IMAP - Internet Message Access Protocol.
Impact tests - Tests designed to reveal the behavior of material of a finished part if it were subjected to impact or shock loading.
Impairment - The generic term for a flaw in phone line quality, usually caused by echo, noise or a reduction in signal strength.
Impedance match - A condition whereby the impedance of a particular cable or component is the same as the impedance of the circuit, cable, or device to which it is connected.
Impedance matching stub - A section of transmission line or a pair of conductors cut to match the impedance of a load. Also called matching stub.
Impedance matching transformer - A transformer designed to match the impedance of one circuit to that of another.
Impedance - The total opposition a circuit, cable or component offers to alternating current. It includes both resistance and reactance and is generally expressed in ohms.
Impedance, characteristic - In a transmission cable of infinite length, the ratio of the applied voltage to the resultant current at the point the voltage is applied. When connected across the cable’s output terminals; the impedance that makes a transmission cable seems infinitely long. For a waveguide, when the waveguide is match-terminated, it is the ratio of rms voltage to total rms longitudinal current at certain points on a diameter.
Impulse - See PULSE.
IMSA - International Municipal Signal Association.
In-band signaling - The transmission of signaling information at some frequency or frequencies that lie within a carrier channel normally used for information transmission.
Incident light - The light that is falling directly over an object.
Incoherent source - A fiber optic light source that emits wide, diffuse beams of light of many wavelengths.
Index edge - Edge of a flat (ribbon) cable from which measurements are made, normally indicated by the location of the printing which is near the index edge. Sometimes indicated by a thread or other identification stripe.
Indoor termination - A cable termination intended for use where it is protected from direct exposure to both solar radiation and precipitation.
Inductance - A property of a conductor or circuit that resists a change in current. It causes current changes to lag behind voltage changes and is measured in henrys.
Induction heating - Heating a conducting material by placing it in a rapidly changing magnetic field. The changing field induces electric currents in the material and I2R losses account for the resultant heat.
Induction - The phenomenon of a voltage, magnetic field or electrostatic charge being produced in an object by lines of force from the source of such fields.
Inductive coupling - Crosstalk resulting from the action of the electromagnetic field of one conductor on the other.
Industrial Ethernet cables - Cables specially designed to withstand the mechanical, chemical and electrical rigors of an industrial environment. Widely used in industrial process control networks.
Infrastructure telecommunications - A collection of those telecommunications components, excluding equipment, that together provide the basic support for the distribution of all information within a building or campus.
Input - A signal (or power) that is applied to a piece of electric apparatus, or the terminals on the apparatus to which a signal or power is applied.
Insertion loss - The signal strength loss that occurs when a piece of equipment is inserted into a line.
Insertion tool - A small, hand-held tool used to insert contacts into a connector.
Inside plant - Everything inside a telephone company central office. See INSIDE WIRING.
Inside wiring - The telephone wiring located inside your premises or building. Inside wiring starts at the telephone company’s demarcation point and extends to the individual phone extensions. Traditionally, inside wiring was installed and owned by the telephone company. Now you can install your own wiring. Most companies installing new phone systems are installing their own new wiring because of potential problems with reusing old telephone company cable.
Insulated radiant heating wire - Similar to blanket wire but heavier construction for applications such as in ceiling panels, buried in ground or driveway and concrete walks.
Insulated splice - A splice with a dielectric medium applied over the connected conductors and adjacent cable insulation.
Insulating (isolating) joint - A cable joint that mechanically couples and electrically separates the sheath, shield and armor on contiguous lengths of cable.
Insulation level - A thickness rating for power cable insulation. Circuits having fault detectors that interrupt fault currents within one minute are rated 100 percent level, within one hour are rated 133 percent level and over one hour are rated 173 percent level.
Insulation stress - The potential difference across an insulator. The stress on insulation is expressed in volts per mill (V/m) or kilovolts per meter (kV/m).
Insulation temperature rating - A maximum temperature assigned to insulations based on laboratory tests.
Insulation thickness - The wall thickness of wire insulation.
Insulation voltage radiant - The nominal phase-to-phase operating voltage of a three-phase cable system.
Insulation - A material having good dielectric properties that is used to separate close electrical components, such as cable conductors and circuit components.
Insulation resistance - The electrical resistance of an insulating material at a specific time and condition as measured between two conductors.
Intel - A semiconductor (chip) manufacturer; one of the sponsors of Ethernet.
Intelligence, intelligent - A term for equipment (or a system or network) that has a built in processing power (often furnished by a microprocessor) that allows it to perform sophisticated tasks in accordance with its firmware.
Interaxial spacing - Center-to-center conductor spacing in paired wire or center-to-center spacing between conductors in a flat cable.
Intercalated tapes - Two or more tapes helically wound and overlapped on a cable.
Interconnect - A connection scheme that provides for the direct connection of individual cables to another cable or to an equipment cable.
Interconnecting cable - The wiring between modules, units or the larger portions of a system.
Interconnection - The joining of devices mechanically to complete an electrical circuit.
Interface device - A device which meets a standard electrical interface on one side and meets some other nonstandard interface on the other. The purpose of the device is to allow a device with a nonstandard interface to connect to a device with a standard interface.
Interface - 1. A shared boundary defined by common physical interconnection characteristics, signal characteristics and meanings of interchanged signals. 2. The equipment that provides this shared boundary.
Interference - Disturbances of an electrical or electromagnetic nature that introduce undesirable responses into other electronic equipment.
Interlace - A scanning process where every other horizontal line is scanned in one field while the alternate lines are scanned in the next field to produce a complete picture frame.
Interleaving - A method used in alarms or activity detection that allows extra frames of video from alarmed cameras to be added to a time multiplexed sequence whilst a state of alarm exists.
Intermediate cross-connect - A cross-connect between first level and second level backbone cabling.
Intermediate frequency - A frequency to which a signal is connected for ease of handling. Receives its name from the fact that it is an intermediate step between the initial and final conversion or detection stages.
Intermediate temper - As applied to aluminum, any temper between soft and hard drawn.
Internal wiring - Electronic wiring that interconnects components, usually within a sealed subsystem.
Internetwork router - In LAN technology, a device used for communications between sub networks; only messages for the corrected sub network are transmitted by this device.
Internetwork - Between two distinct networks.
Interstice - The space or void between assembled conductors and within the overall circumference of the assembly.
Intranet - Within one network.
Intrinsically safe - Incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most ignitable concentration.
Ionization factor - This is the difference between percent dissipation factors at two specified values of electrical stress; the lower of the two stresses is usually so selected that the effect of the ionization on dissipation factor at this stress is negligible.
Ionization voltage - The potential at which a material ionizes. The potential at which an atom gives up an electron.
Ionization - 1. The creation of ions when polar compounds are dissolved in a solvent. 2. When a liquid, gas or solid is caused to lose or gain electrons due to the passage of an electric current.
IP (Internet Protocol) - A procedure used to forward Internet traffic to neighbor gateway nodes. IP is also used in ADS gateway nodes to forward traffic between networks. IP’s primary function is Internet routing and packet fragmentation and assembly.
ipAssuredSM - An infrastructure assurance program that matches the cabling infrastructure to the security equipment based on the technical, application and life-cycle requirements of the user.
IP-Class 1+SM - An Anixter ipAssured infrastructure cabling assurance that will meet life-cycle requirements of 1 to 5 years.
IP-Class 10+SM - An Anixter ipAssured infrastructure cabling assurance that will meet life-cycle requirements of 10 or more.
IP-Class 5+SM - An Anixter ipAssured infrastructure cabling assurance that will meet life-cycle requirements of 5 to 10 years.
Ips - In video, it stands for images per second. It is also sometimes called pictures per second (pps).
IR drop - A method of designating a voltage drop in terms of both current and resistance.
IR drop - A method of designating a voltage drop in terms of both current and resistance.
IRC (incrementally related carrier) - In CATV, an offset band of channel frequencies.
IRE - Institute of Radio Engineers.
Irradiation - In insulations, the exposure of the material to high-energy emissions for the purpose of favorably altering the molecular structure.
ISDN (Integrated Services Digital Network) - A CCITT standard that covers a wide range of data communication issues but primarily the total integration of voice and data. Digital phone lines that allow transmission of video signals via fast scan at speeds of 128 kbps; used with terminal adapters.
ISI (inter symbol interference) - In multimode fiber it is caused by DMD (differential mode delay).
ISM (industrial, scientific and medical) - Usually used to define the unlicensed RF bands used for wireless transceivers as defined by FCC regulations (47CFR parts 15 and 18). These are 5.8 GHz, 2.4 GHz and 900 MHz.
ISO (International Organization for Standardization) - Reference model for open systems interconnection; a standard approach to network design that introduces modularity by dividing the complex set of communications protocols into more manageable, functional slices.
ISO 9000 - A set of quality standards widely used around the world.
ISO Reference Model for OSI (International Organization for Standardization Reference Model for Open Systems Interconnection) - A standard approach to network design which introduces modularity by dividing the complex set of functions into more manageable, self-contained, functional slices. These layers, from the innermost layers, are as follows: 1. Physical Layer: Concerned with the mechanical and electrical means by which devices are physically connected and data are transmitted. 2. Link Layer: Concerned with how to move data reliably across the physical data link. 3. Network Layer: Provides the means to establish, maintain, and terminate connections between systems; concerned with switching and routing of information. 4. Transport Layer: Concerned with end-to-end data integrity and quality of service. 5. Session Layer: Standardizes the talk of setting up a session and terminating it; coordination of interaction between end-application processes. 6. Presentation Layer: Relates to the character set and data code which is used, and to the way data is displayed on a screen or printer. 7. Application Layer: Concerned with the higher level functions which provide support to the application of system activities.
Isochronous - A form of data transmission in which individual characters are only separated by a whole number of bit-length intervals. Contrast with ASYNCHRONOUS in which the characters may be separated by random-length intervals. A form that will not tolerate delay. (e.g., Real-time V.V.)
Isolation loss - The amount of signal attenuation of a passive device from output port to tap outlet port.
Isolation - The ability of a circuit or component to reject interference, usually expressed in dB.
ITU - International Telecommunications Union.
IW - Inside wire.
IWCA - Inside wiring cable.