While most standards in the tele-communications industry are revised infrequently, the commercial building telecommunications standard, ansi/tia/ eia-568a, is more of a living document. The working committee of the Telecommunications Industry Association (tia--Arlington, VA) that is responsible for the standard makes ongoing changes and enhancements to keep pace with the evolving needs of the marketplace.
In late 1996, the TR-41.8.1 working committee set out to make the next release of the 568A standard more user-friendly, as well as to allow for easier and quicker revisions. To achieve this goal, the committee decided that the standard would be split into four separate documents. The main document, tia/eia-568b.1, will contain cabling-system level recommendations for the end-user, including topology, recommended media, cabling design and installation issues, and link and channel performance requirements.
Three other documents will contain component-level specifications primarily intended for manufacturers and suppliers of cabling products: tia/eia-568b.2 for unshielded twisted-pair (utp) cable specifications; tia/eia-568b.3 for glass optical-fiber specifications; and tia/eia-568b.4 for shielded and screened twisted-pair (stp, sctp) specifications. Task groups are currently working on these medium-specific documents, and they will make recommendations for changes to the main document as well. No date has been set for the release of the next full revision of the standard, ansi/tia/eia-568b.
The Optical Fiber Task Group of tia`s TR-41.8.1 committee has also met recently to discuss the building wiring standard. Its discussion represents work-in-progress and has not been approved or submitted for ballot. However, the group is making progress toward a standard that will facilitate the use of optical fiber-to-the-desk:
- The task group requested a new bandwidth test to use with multimode fiber under restricted launch conditions experienced with the new high-speed transceivers that have been introduced for gigabit speeds. The group asked tia fo-2.2, which is already addressing this issue, to focus on the needs of the building- cabling industry and specifically determine the degree of correlation between this new test method and the existing overfilled test method.
- New fiber-optic connectors offer advantages for premises fiber-optic cabling. Working with TR-41.8.1, the task group has developed a list of criteria for evaluating these devices and has committed to making recommendations by February 1998. These recommendations will then be sent out for industry ballot.
In the development of tia/eia-568b.3, the most significant issues discussed include the following:
- Compliance with international standard iso/iec-11801--The group will make decisions case-by-case to resolve conflicts.
- New bend radius--The group is soliciting comments about adding a 1-inch minimum bend-radius requirement for 2- and 4-fiber horizontal cables in a laid-in installation or a no-stress environment. This discussion addresses fiber-to-the-desk issues such as surface-mount and office-furniture raceway systems.
- Connectors--tia fo-6.3 has developed a draft document for the optical, mechanical, and environmental performance requirements of premises optical connectors. This document will replace the existing specifications in tia/eia-568a.
- Telecommunications outlets--The group believes that existing requirements to maintain bend radius and store 1 meter of cable in telecommunications outlets is overly restrictive and is, therefore, considering deleting these requirements.
The Optical Fiber Task Group also discussed recommendations for changes to the main document concerning glass optical-fiber cabling. Among the significant changes discussed were
- complete incorporation of tia`s telecommunications systems bulletin TSB-72, "Centralized Optical Fiber Cabling Guidelines," into the release of tia/eia-568b.1;
- revising bandwidth considerations in the informative annex to address the latest transceiver technology, specifically short-wavelength lasers;
- expanding existing link-performance recommendations to include attenuation performance requirements for open-office cabling, centralized optical-fiber cabling, and intrabuilding backbone cabling.
Your comments and recommendations on these proposed changes to the commercial building telecommunications cabling standard are welcome and can be sent to the chairman of the Optical Fiber Task Group by e-mail: email@example.com.
Tony Beam is a member of the tia Fiber Optics lan Section and is the premises marketing director for amp Inc. (Harrisburg, PA). He is also chairman of the Optical Fiber Task Group of tia TR-41.8.1.