Structured Wiring s Component Parts in Software

Generator QR Code in Software Structured Wiring s Component Parts

Structured wiring defines a series of wiring elements that are assembled and connected to form telecommunications links (Fig 12) The basic elements are the horizontal wiring structure, the backbone wiring structure, and a series of cross-connect structures that include the main cross-connect, the intermediate cross-connect, and the horizontal cross-connect These last three elements are usually contained in dedicated rooms within a building For example, the horizontal cross-connect is contained in the TR, and is identified as such The other rooms are often identified by their structure names, main cross-connect (MC) or intermediate cross-connect (IC) Backbone cable runs between the cross-connect structures, while horizontal wiring runs from the TR to the individual work areas This hierarchy is illustrated in Fig 13 The structure holds within a single commercial building and between buildings, as on a campus Although the structured wiring concept actually comes from the telephone industry, and thereby predates data uses of twisted-pair cabling, its use is particularly critical to modern data networks Structured wiring defines the precise maxi-

mum distances, types of connections, grade of cable and connectors, and installation practices necessary to provide a reliable and flexible data and voice cabling infrastructure The embodiment of modern structured data/voice wiring is the TIA/EIA-568-C standard for North America and the ISO/IEC 11801 standard for the European Community For the most part, the balance of the countries around the world use one of these standards for their local cabling guidelines Fortunately, these primary standards are becoming more and more coordinated through a process of international technical cooperation called harmonization The next few sections describe the major wiring strategies of horizontal and backbone cabling Horizontal wiring takes the bulk of our attention in LAN wiring, as it is the most complex structure, and offers the most challenges to designer and installer alike Horizontal Wiring Structure The basic component of the structured wiring system is the horizontal wiring (cabling) structure Horizontal cabling consists of the cable and connections from the wall or other jack at the user workstation outlet to the wire termination in the TR As shown in Fig 13, the horizontal wire may include a punchdown block, cross-connect wire, and a patch panel However, it does not include hubs, routers, or network adapters Horizontal cable is defined in TIA/EIA-568-C Commercial Building Telecommunications Wiring Standard, and is the Permanent Link (minus cross-connect and test cables) originally defined in TSB-67, Transmission Performance Specifications for Field Testing of Unshielded Twisted-Pair Cabling Systems In practice, horizontal wire is routed directly from the TR to the workstation, without any intermediate splice points, cable junctures, or taps, as might be common practice in traditional telephone wiring This direct-wiring technique is referred to as a home run Various wiring standards put special qualifications on horizontal wiring Some of these may limit the types of components, such as cross-connects, that may be a part of horizontal wiring More specifically, you should make sure that you use cable and components that are rated for the data rates you intend to use For exam-

ple, if you are installing a Category 5e (TIA/EIA-568-C) facility, you must use Category 5e rated jacks, cable, patches, and user cords If you use a cross-connect field to connect between the station cables and a patch panel, the cross-connect wire must also be rated Category 5e The same is true of Category 6 all components including cables, connectors, and cords must be Category 6 rated to achieve Category 6 performance Category 7 is the first standard that allows deviation from the ubiquitous 8-position modular connector (AKA RJ-45) The connectors and the cables are quite different in appearance from the lower-rated categories, so a Category 7 installation is a little easier to spot But, to the casual eye (and perhaps