Field testing--an integral part of a standard

Enhanced-performance Category 5 cabling has become the most active project within the Telecommunications Industry Association`s (tia--Arlington, VA) TR-41 User Premises Telecommunications Equipment Committee. The Unshielded Twisted-pair (utp) Systems Task Group of TR-41.8.1 is chartered with writing an addendum for tia/eia-568a to specify additional parameters in support of new high-speed applications such as Gigabit Ethernet.

Sep 1st, 1997
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Terry Cobb

Datacom Technologies

Enhanced-performance Category 5 cabling has become the most active project within the Telecommunications Industry Association`s (tia--Arlington, VA) TR-41 User Premises Telecommunications Equipment Committee. The Unshielded Twisted-pair (utp) Systems Task Group of TR-41.8.1 is chartered with writing an addendum for tia/eia-568a to specify additional parameters in support of new high-speed applications such as Gigabit Ethernet.

Historically, field verification has often been an afterthought in a standard. In a letter from the chairperson of the ieee 802.3 Ethernet standard committee, however, it was requested that field testing "be an integral part of a standard to require the prequalification of an installed link with a handheld tester."

At a recent interim meeting of the utp Systems Task Group, this addendum work was separated into two priorities. The first priority deals with the additional parameters of equal-level far-end crosstalk--the ratio of the attenuated signal on one pair to the crosstalk on an adjacent pair at the far end--and return loss, and with characterizing these for the installed base of cabling, along with defining their field tests.

What is now referred to as "enhanced Category 5 cabling" will be studied following this effort, and the group will address multidisturber cross-talk characteristics and cabling balance. The distinction between these two efforts is that the first will more accurately specify what has been installed under the existing tia/eia-568a standard, while the second will characterize the cabling improvements that are now available. However, debate still exists on how to identify enhanced Category 5 cabling. The completion of this addendum is scheduled to coincide with the adoption of the copper-cabling portion of the Gigabit Ethernet standard, which should be released in mid-1998.

In addition to these activities, the utp Connector Task Group of TR-41.8.1 is continuing its effort to define a test for patch cords. Significant progress has been made in understanding the effects of plug/jack interaction with the cord. The group has also proposed addressing the issue of testing zone cabling. Often, the initial cabling installation only routes cable to a consolidation point or a multiuser outlet. Today, no defined test or requirement to these intermediate points exists.

Meanwhile, the Fiber Optic Task Group has agreed to investigate a new fiber-optic connector that would be less complex than the duplex SC. It will research a connector that is comparable in size to an 8-pin modular plug.

Click here to enlarge image

Click here to enlarge image

The ratio of the attenuated signal on one pair to the crosstalk on an adjacent pair at the far end is called equal-level far-end crosstalk.

Terry Cobb is the president of Datacom Technologies (Everett, WA), a manufacturer of field-test equipment.

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