Published In January 2002
The practice of installing cabling systems for a specific application or each new application is outdated. Structured cabling systems (SCS) save time and money when incorporating upgrades; moves, adds, or changes; integrating a small network into a large system; or migrating to a technology offering higher performance levels. TIA/EIA-568B.1 Commercial Building Telecommunications Cabling Standard provides the guidelines and general recommendations for SCS. With the increasing complexity of standards and systems, as well as warranty issues, end-users often install an all “under one umbrella” solution, which allows for easy-to-accommodate nondisruptive network expansion. Entrance facility The telecommunications entrance facility is the building’s point of entrance for both public and private network cables including the entrance point at the building wall and continuing to the entrance room or space. This SCS subsystem requires design considerations relevant to fire and building codes and any demarcation point issues. Most outside plant (OSP) cables are not flame-retardant, and the National Electric Code (NEC) limits the length of exposed, nonfire-rated entrance cable to 50 feet from the point of entrance. If more than 50 feet is required between the entry point and termination point, the cable will have to be installed in a conduit, and depending on the cable type, may have to be installed in a grounded metal conduit; refer to the NEC for specifics. If the cable is unlisted and conduit is not an option, a splice point must be employed, which transitions the outside plant cable to an indoor-rated design. Equipment room The equipment room is a centralized space for data and voice network equipment, media converters (which change electrical signals into light pulses and vice versa), security monitoring equipment, and any other active equipment that serves building occupants. It also contains the main cross-connect and terminations for the telecommunications distribution cables. The equipment room functions are sometimes combined with those of the entrance facility in the same space. If these two SCS subsystems share a space and are located within 50 feet of the entrance point, “splice and play” products offer a labor-saving, cost-effective solution. They provide the contractor with an enclosure that is prewired with preterminated fiber pigtails. The only on-site work necessary is splicing the OSP cable to the prewired pigtails. Eliminated from the on-site work are the time-consuming tasks of installing loose-tube breakout kits, fiber termination, and routing the fiber pigtails in the enclosure. Backbone cabling Backbone cabling, which can run within or between buildings, provides the connections between the telecommunication rooms, equipment room, and entrance facility. It consists of transmission media to support voice and data applications. The main cross-connect; intermediate cross-connect; and terminations for the horizontal cross-connect, equipment room, and entrance facility are all of its components. Typically, fiber has become the accepted medium of choice in today’s data backbone. It is important to understand the TIA/EIA 568B.1 standard recommendations as they relate to topologies and the suggested maximum backbone cabling distances for the different fiber types. Telecommunication room and horizontal cabling The telecommunication room is enclosed space for housing telecommunications equipment, cable terminations, and the horizontal cross-connect, which join the backbone cable and horizontal cabling. This equipment is similar to that in the equipment room, including the media converters. Horizontal cabling is the cabling between and including the work area telecommunications outlet/connector and the horizontal cabling in the telecommunication room. While copper is still the most popular horizontal cabling medium, more end-users are choosing it for their desktop cabling, because it can dramatically cut local area network ownership costs. Work area The work area is a building space where the occupants interact with the telecommunications terminal equipment. Located here is the telecommunications outlet/connector, a device placed at a user’s workstation for horizontal media termination and network equipment connection. While the fiber optic duplex SC connector is still recommended for the telecommunications outlet, TIA/EIA 568-B.3 allows the use of alternative connector designs, called small form factor connectors. These connectors provide a higher-density solution than the SC offers, due to their smaller footprint. With the establishment of TIA/EIA standards, the benefits of fiber optic technology are being realized and used when designing a structured cabling system solution. A contractor installing a fiber optic cabling system can save time and money by employing preterminated solutions, which can easily accommodate today’s requirements and tomorrow’s applications. MIKULA is marketing manager for FiberSmart and contractor training programs for Pass & Seymour/Legrand. He can be reached at (315) 468-6211.