Patrick McLaughlin
While product manufacturers continue to joust over whether the copper or fiber-optic cabling medium best provides the high bandwidth users will require, cabling contractors and cabling-plant managers are tasked with finding the meaningful information behind the marketing hype. The Broadband `97 conference provided cabling professionals with an opportunity to hear what industry experts had to say on this topic, to ask questions of those experts, and to decide for themselves the direction in which the cabling industry is likely to be headed.
Jim Hayes of Fotec Inc. (Medford, MA), former president of the Fiber Optic Association (Boston, MA), opened the two-day conference by citing that technically, both copper and fiber are workable in a high-speed network, but most Category 5 unshielded twisted-pair (utp) applications will not support high-bandwidth networks because they are installed incorrectly. Adding to the confusion, he said, are the soon-to-be-asked questions of whether to use Category 5, 6, or 7 cable.
Alan Flatman, principal engineer with lan Technologies (Congleton, Cheshire, UK), provided attendees with information on the European market`s consideration of a Category 6 copper cable. He explained that the possibility of Category 6 cable is seen as both an opportunity and a threat. The opportunity for higher bandwidth is evident, but Flatman emphasized what he called the risks and disadvantages.
He said significant pair-to-pair crosstalk enhancement can only be achieved by shielding individual pairs, resulting in bulky and inflexible cables. He also pointed to performance-verification problems associated with Category 5 cable, and suggested that a move to Category 6 would result in further confusion. Specifically, he said, Category 6 cable would require development of 600-megahertz testers--a time-consuming undertaking. He also stated that there are no emerging or planned applications that require copper cabling with performance greater than 100 MHz.
Copper cabling also had its proponents at the conference. Paul MacDonald of Lucent Technologies` Norwood, MA, facility foresees a natural progression from 100 to 1000 megabits per second over copper cabling, much like the progression from 10 to 100 Mbits/sec. He said the Gigabit Ethernet Alliance of the Institute of Electrical and Electronics Engineers (ieee--Piscataway, NJ) will probably provide a standard for gigabit-to-the-desk by March 1998. He also said that Category 5 cable will probably support gigabit transmission over horizontal distances of 50 to 60 meters, or will provide full horizontal-distance support when coupled with new, expensive, and complex hub electronics.
The alternative to this, he added, will be a more robust cabling network that uses less complex, less expensive hub electronics and integrated circuit chips. According to MacDonald, the exceptional balance built into twisted pairs; the electronic and magnetic characteristics inherent in this cable, which is still under development; and a systems approach to cabling will allow gigabit speeds over utp copper cable.
Optical fiber supporters were themselves divided into different camps about the fiber-versus-copper question. Patricia Dawson of Sturbridge, MA-based SpecTran spoke on behalf of the Telecommunications Industry Association`s (Arlington, VA) Fiber Optics lan Section, explaining the benefits of glass optical fiber. Then, Edward Berman of Boston Optical Fiber (Westborough, MA) touted plastic optical fiber (pof) as an inexpensive short-haul solution, and Dana DuToit of SpecTran claimed that hard-clad silica optical fiber expands the applications available to pof.
Paul Polishuk of igi Consulting (Boston, MA) presented initial results of a premises-wiring study his firm is conducting. Among his early conclusions are that users and network-equipment vendors remain attached to Category 5 cabling; the copper cabling market will continue to expand but will feel increasing pressure from fiber as networking speeds exceed 155 Mbits/sec; copper-cable manufacturers will begin manufacturing fiber-optic cable; differentiation among copper-cable manufacturers will be achieved through higher-speed cable designs; and beyond 155 Mbits/sec, utp cable will require digital signal processing techniques and advanced modulation.
According to Information Gatekeepers Inc. (igi--Boston, MA), which organized the conference, 200 individuals participated in Broadband `97, which covered more than just the copper/fiber debate. Other discussion topics included the reality of Asynchronous Transfer Mode, wireless lans and their implementation, and standards development. The two-day conference was preceded by a day of tutorials covering similar topics, such as testing and troubleshooting fiber-to-the-desk systems; designing pof links and lans; copper-based systems; the European premises cabling market; and wireless lans.
According to igi sources, next year`s show will include a focus on residential cabling. For more information, call igi at (617) 232-3111.
