9.6 Basics of Wiring Closets and Patch Panels 9.6.1 Wiring closet Instructor Note Wiring closets, covered extensively in Chapter 8, are reviewed A wiring closet serves as a central junction point for the wiring and wiring equipment used to connect devices in a local area network (LAN). It is the center point of a star topology. A wiring closest can either be a specially designed room or cabinet. Normally, the equipment in a wiring closet includes:patch panels wiring hubs bridges switches routers Web Links Cabling Glossary Cable Termination and Installation 9.6 Basics of Wiring Closets and Patch Panels 9.6.2 Reason for MDFs and IDFs Instructor Note The concepts of MDFs and IDFs, covered extensively in Chapter 8, are reviewed. It is not unusual for large networks to have more than one wiring closet. Usually, when this occurs, one wiring closet is designated as the main distribution facility (MDF). All others, referred to as intermediate distribution facilities (IDFs), are dependent on it. A topology such as this is described as an extended star topology. Web Links Cabling Glossary Cable Termination and Installation 9.6 Basics of Wiring Closets and Patch Panels 9.6.3 Patch panel Instructor Note The structure and importance of patch panels is introduced. It is helpful if you have some unmounted patch panels to pass around to allow the students to see them in detail. In an Ethernet LAN star topology, the horizontal cabling runs, which come from the work areas, usually terminate at a patch panel. A patch panel is an interconnecting device through which horizontal cabling runs can be connected to other networking devices, such as hubs and repeaters. More specifically, a patch panel is a gathering of pin locations and ports. A patch panel acts as a switchboard, where horizontal cables coming from workstations, can connect to other workstations to form a LAN. - In some instances, a patch panel can also provide locations for devices to connect to a WAN, or to the Internet. This connection is described by TIA/EIA-568-A as a horizontal cross-connect (HCC). Web Links Cabling Glossary Cable Termination and Installation 9.6 Basics of Wiring Closets and Patch Panels 9.6.4 Structure of a patch panel Instructor Note Remind students the back of the patch panel is built similarly to the back of the RJ-45 jacks they worked with earlier. To understand how a patch panel provides for the interconnection of horizontal cabling runs with other networking devices, examine its structure. Rows of pins, much like those in an RJ-45 jack, are located on one side of a patch panel, and just as they are on the jack, the pins are color-coded. To make electrical connections to the pins, you must use a punch tool to punch down the wires. Keep in mind that proper wire sequence is critical for best network performance. Therefore, when laying down the wires at the patch panel, make sure the colors of the wires correspond exactly to the colors indicated on the pins. The wire and pin colors are not interchangeable. On the opposite side of a patch panel there are ports. They resemble the ports on faceplates of telecommunications outlets in the work area. Like the RJ-45 ports, the ports on patch panels take the same size plugs. Patch cords that connect to these ports make possible the interconnection of computers and other network devices (e.g. hubs, repeaters, and routers) that are also attached to the patch panel. Web Links Cabling Glossary Cable Termination and Installation 9.6 Basics of Wiring Closets and Patch Panels 9.6.6 Punch tools Instructor Note Remind the students that they already know how to use a punchdown tool from their work with RJ-45 jacks and that the same procedure applies with patch panels. The patch panel type determines whether you use a 110 punch tool or a Krone punch tool. The panel depicted in the graphics in this lesson is a 110. Check to see which one you will need before you begin work. A punch tool has spring-loaded actions. This allows it to perform two functions at the same time. As it pushes the wire between two metal pins, and skins the sheath from the wire (so that it can make an electrical connection with the pins) the punch tool's blade also cuts off any extra wire. Occasionally the punch tool may fail to make a clean cut. When this happens, twist the cut ends of the wires gently, then remove them after they have been punched. When you use the punch tool, be sure to position it so that the blade faces away from where the wire enters each pin location. If you fail to take this precaution, you may cut the wire so that it falls short of its electrical connection point. Web Links Cabling Glossary Cable Termination and Installation 9.6 Basics of Wiring Closets and Patch Panels 9.6.7 Mounting a patch panel Instructor Note Mounting of patch panels on brackets, racks, and cabinets is discussed. Emphasize that all of this is part of keeping the cabling structured and easy to manage. You can mount patch panels on walls (with the help of brackets), you can stand them in racks, or you can place them in cabinets (equipped with interior racks and doors). One of the most commonly used pieces of equipment is the distribution rack. A distribution rack is a simple skeletal frame that holds equipment such as patch panels, repeaters, hubs, and routers that are used in the wiring closet. It can range in height between 1-1.9 m. The advantage of a distribution rack is that it allows easy access to both the front and the back of the equipment. To ensure stability, a floor plate attaches the distribution rack to the floor. While a few companies currently market a .5 m wide rack, the standard, since the 1940s, has been the .48 m rack. Web Links Cabling Glossary Cable Termination and Installation
