tia generates specifications for fibers and cables

By WILLIAM B. GARDNER

The Telecommunications Industry Association`s (tia`s) Working Group FO-6.6.2 on Fiber Specification Documents, chaired by Steve Swanson of Corning Inc., has recently balloted a nearly complete set of specifications for optical fibers.

There are four tiers in tia`s hierarchical specification system. The Generic Specification tia/eia-4920000-B (Nov. 1997) delineates specifications common to all optical-fiber types. Each Sectional Specification extracts portions of the Generic Specification that are applicable to one class of fiber, such as graded-index multimode, dispersion-shifted singlemode, and non-zero-dispersion singlemode. Other specifications not appearing in the Generic tier can also be introduced. For each class of fiber, a Blank Detail Specification gives directions for writing the document in the fourth tier, the Detail Specification. The Detail Specification provides detailed fiber specifications for specific applications and is intended to be referenced in the buyer`s procurement document. Detail Specifications can be written by either a tia engineering committee or a manufacturer. All of these specifications can be purchased from Global Engineering Documents in St. Louis, MO, tel: (800) 854-7179 or fax: (314) 726-6418.

The first objective of these specifications is to establish fiber performance for specific applications. This is done by defining specifications--including tolerances--for fiber parameters and providing a list of methods for measuring these parameters.

The second objective is to provide quality assessment (QA) under the U.S. National Electronic Components Quality Assessment System, known as necq. This system is patterned after the International Electrotechnical Commission`s international QA system, or iecq. An important component in the necq system is a system supervising inspectorate, whose job is to validate the implementation of the necq procedures. There is no inspectorate for fiber or cable at the present time nor is there expected to be in the foreseeable future, so the second objective is not, strictly speaking, being met.

Nevertheless, in meeting the first objective, the tia specifications establish expectations in the industry for performance of the various fiber types. Organizations that write system standards (such as Fiber Distributed Data Interface and Gigabit Ethernet) prefer to concentrate their limited resources on interface standards. This usually means adopting the fiber standards written by other organizations such as the tia.

tia Subcommittee FO-6.7 on Fiber Optic Cable, chaired by Eric Loytty of Siecor Corp., plans to adopt a cable specification written by the Insulated Cable Engineers Association (icea). The "icea Standard for Optical Fiber Outside Plant Communications Cable" ansi/icea s-87-640-1992, Revision L (1/14/98), states that "it is the responsibility of the manufacturer to establish a quality assurance system consistent with ansi/asqc Q9000-1 and Q9004-1 [equivalent to iso-9000 and iso-9004, respectively], or an alternate system acceptable to the user. When the user wishes to require a specific quality assurance program or special testing procedures, agreement between the user and the manufacturer should be reached before the order is placed."

This alternative to necq is one of several that are being considered for the tia fiber specifications. q