Highlights on New Category 6 Standard

The Telecommunications Industry Association (TIA) has published its long-awaited standard for Category 6 data cabling and components. Officially known as ANSI/TIA/EIA-568-B.2-1, the standard is an addendum to the TIA/EIA-568-B standard for commercial building telecommunications cabling. Highlights include:

¥ Twice the bandwidth of Category 5e cable.

¥ Patch cord interoperability with modular (RJ-45 type) connectors.

¥ All components and cabling tested to 250 MHz.

¥ Backward compatibility to systems wired with Categories 3, 5 and 5e cable.

¥ Open standard that allows products from different vendors to work together.

Those last two points are critically important from the installer's point of view. In the communications field--as compared with traditional electrical power products such as cable, raceways and panelboards--products evolve so fast that industry standards sometimes have to race to catch up.

Category 5e cabling systems became a widespread commercial reality long before the ink was dry on that TIA standard. And while the Category 6 standard was released only a few months ago, companies such as AMP NetConnect, NORDX/CDT, Lucent Technologies and ADC all introduced Category 6 cabling solutions for voice-data-video networking as long ago as 1999. However, the crucial distinction is that these early prestandard releases were all proprietary, end-to-end systems using cable and hardware from a single vendor or, in some cases, teams of allied vendors.

Open standards, backward compatibility, testing

One of the stated goals of TIA committee TR-42 in developing the new Category 6 requirements was to have an open standard, where different vendors' cabling, connectors, patch cords and other components can be mixed and matched. This is important because it matches the reality of the VDV market. True, most new communications networks built from scratch are proprietary systems put in by certified installers and backed by manufacturers' extended warranties. But it is the moves, adds and changes on less-demanding, small-office networks that form the bread-and-butter work of many data contractors. And this requires the flexibility and freedom to buy any brand of cable or part and piece it into the existing system with the confidence they will operate together satisfactorily.

Backward compatibility is important for the same reason. During the development of TIA-568-B.2-1, there were concerns that the final Cat. 6 technology might wind up using different conductor sizes, cable construction or connector designs that would make it impossible to repair or upgrade parts of an existing Cat. 5 or 5e network using newer Cat. 6 cable and piece-parts.

Both in-house maintenance departments and communications contractors can breathe a sigh of relief that this nightmare didn't happen. The backward compatibility built into the final standard ensures that existing applications operating on older Cat. 3, 5 or 5e systems will also communicate over Cat. 6 cable and components. Naturally, the transmission requirements of such blended systems will be subject to the limitations of the "weakest link" or lowest-rated element.

And another matter of practical importance, TIA-568-B.2-1 clearly defines field-testing procedures for Category 6 installations. "The standard clears up confusion concerning the testing/certification of the cabling infrastructure," said Mary Germershausen, director of systems technology for the National Electrical Contractors Association. "Contractors will have to select the tester they feel comfortable with and check with the manufacturer to make sure that it is compliant with Level III specifications."

A global phenomenon

As already noted, the formal industry standards for Category 6 were a long time coming together. They don't establish new performance requirements for Cat. 6 data systems so much as confirm and ratify what has already been present in the real world for a while.

Other standards developers have also been working around the globe on performance and applications issues:

¥ ISO/IEC 11801, which refers to Category 6 cabling as "Class E" and includes components as well as cabling, is expected to be published near the end of this year.

¥ CENELEC EN-50173 contains Category 6 cable and component specifications that are essentially the same as TIA/EIA-568-B.2-1 and is also expected at the end of 2002.

¥ ANSI/TIA-854, Standard for Gigabit Ethernet over Category 6 Cabling, was published last year.

¥ ATM Forum published a standard last year defining the ATM (asynchronous transfer mode) version of Gigabit Ethernet. ATM is principally used for backbone and long-haul data applications.

Of course, even as you read these words celebrating the eventual "completion" of Category 6 standards, industry technical committees are hard at work, and have been for some time, trying to define the next generation of copper twisted-pair cabling and components: Category 7. And, of course, there are others who feel that the whole effort is doomed, because in their view "Cat. 7" will be fiber optic. EC

STAUFFER is executive director of standards and safety for the National Electrical Contractors Association (NECA). He may be reached at brooke@necanet.org.

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