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Network Cabling Solutions Appendix Horizontal Cabling The cabling between and including the telecommunications outlet and the horizontal cross-connect. Horizontal Cross-Connect (HC) A cross connect of horizontal cabling to other cabling, e.g., horizontal, back bone, or equipment. lntermediate Distribution Frame (IDF) 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. Hub 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. lntrabuilding Backbone Telecommunications cable(s) that are part of the building subsystem that connect one equipment room to another. Hybrid Cable An assembly of two or more cables, of the same or different types or categories, covered by one overall sheath. Jumper Wire An assembly of twisted pairs without connectors on either end used to join telecommunications links at a cross connect. I K Infrastructure 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. Keying The mechanical feature of a connector system that guarantees correct orientation of a connection or prevents the connection to a jack, or to an optical fiber adapter of the same type intended for another purpose. Insertion Loss 1. 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. 2. 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. L Insulation Displacement Connection (IDC) 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. Intelligent Hub A hub that performs bridging and routing functions in a collapsed backbone environment. lnterbuilding Backbone Telecommunications cable(s) that are part of the campus subsystem that connect one building to another. Interconnection A connection scheme that provides direct access to the cabling infrastructure and the ability to make cabling system changes using equipment cords. Intermediate Cross-Connect (IC) 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). J Link 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. Local Area Network (LAN) 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 drives intended for the local transport of data, video, and voice. Local Exchange Carrier (LEC) The local regulated provider of public switched telecommunications services. Longitudinal Conversion Loss (LCL) 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. m main Cross Connect (mC) A cross connect for first level backbone cables, entrance cables, and equipment cables. modular Jack 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. modular Plug 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. 226 For product information visit www.hellermann.tyton.com or call 800.537.1512