In network design, more emphasis is often placed on selecting the active equipment than on building the passive part of the network. Many network problems are caused by neglect of passive components. This article presents an overview of various telecommunications closet (TC) technologies as they pertain to network installations and maintenance.
The TC is the space that accommodates the horizontal cross-connect, cabling, and cabling components. These items are considered mere complements to the proper function of the active equipment. However, the contractor must recognize the importance of the TC and the technology available to ensure an optimally functioning network.
There is at least one TC per building floor. It serves as the connection point between the backbone and horizontal distribution pathways, which feed work area outlets on building floors. The TC contains primarily passive cabling components, but if it houses inter-building entrance facilities, it may also contain active devices required to interconnect equipment to the workstation.
How important is the TC to the installation? Imagine that the active equipment represents a fast, heavy-duty freight truck that can zip from destination to destination. The TC is a main bridge that connects many streets, which allows passage to various locations. Let’s say you are a general contractor scheduled to deliver materials to three of your largest ongoing projects. Imagine zipping along in your truck and reaching a bridge, only to find that it is out. However fast your truck is, you will not be able to deliver the materials that day without some bridge maintenance. Passable roads are as essential to delivering materials to projects as a well-maintained TC is to delivering information to its final destination.
Using proper installation practices, the correct type of cabling, patch panels, or punch down blocks to distribute the signals from the equipment to the workstation alone does not ensure proper system performance. All of these factors and more are necessary to ensure proper performance long after the equipment and cabling installation is completed. To ensure post-installation system performance, the designer must consider administration, cable management, and power distribution.
Good network administration and record keeping is not only valuable at installation time, it is also important for maintenance. Administration is helpful in two post- installation practices—fault finding and preventive maintenance. Good record keeping can also lessen downtime, which is sometimes caused by improper equipment port connections.
Administration helps a technician navigate the TC more efficiently. ANSI/TIA/EIA-606 provides guidance for the telecommunication administration. Many types of labeling systems are offered for cables and patch panels, such as handheld labeling devices, adhesive labels with downloadable labeling software, and plastic icon inserts.
During installation, contractors must adhere to strict standards on bend radius, unravel length, cable length, cable tension, and routing. Cable management assists with meeting the post-installation requirements by ensuring the cables are supported properly and not bent or strained beyond the stated standards. Aside from support, cable management provides organization that reduces clutter and helps with quick cable location for necessary moves, adds, and changes. Cable management must be designed into the network system and included in the installation phase, since it is virtually impossible to install once the patch panels are terminated. There are many types of cable management, including vertical and horizontal management, front and rear cable management, ducts, and cable management bars.
When the TC contains active equipment, convenience outlets that mount on the rack are an excellent solution for power distribution. Every room in a building has wall power outlets. This includes the telecommunications room. However, the standards recommend at least 3 feet of working space in front and back of the equipment rack. Using extension cords to distribute power to the rack creates a safety hazard to the personnel working in the telecommunications room as well as the potential for network downtime. If the network is forced offline because the power is accidentally removed from the equipment, all the data being transported during that time is lost and must be recovered. Rack-mounted convenience outlet strips become a vital solution. These outlet strips are available for vertical and horizontal power distribution. Some units may also include uninterruptible power supplies (UPS) and surge suppression.
Proper administration, cable management, and power distribution in the TC are essential to an effective telecommunications network. This reduces unnecessary downtime and lessens disruption when maintenance is required. Having the best possible active equipment does not guarantee performance. Both active and passive equipment of the network system require careful thought during the design phase, while keeping post-installation system maintainability in mind. EC
SANTANA is product manager, data communications, for Pass & Seymour/Legrand. She can be reached at (315) 468-6211.