Arlyn S. Powell, Jr.
In the March 1997 issue of Cabling Installation & Maintenance (page 4), we published a fax-back survey asking readers about the need for a Category 6 cabling designation. In April ( page 4), we again surveyed our readers, this time on the trends they consider important in the cabling industry. In addition, we maintained a survey form on our Web site for several months, asking Internet visitors what they thought about the magazine.
It is now time to report what you and your peers had to say about these and other vital cabling-industry topics.
Reaction to Category 6 mixed
The March survey on Category 6 drew 30 responses, mostly from the United States, but some from as far away as Greece and South Africa.
Asked whether the Telecommunications Industry Association (tia--Arlington, VA) should develop a performance specification for Category 6 unshielded twisted-pair (utp) copper communications cable, respondents were about equally split, with 47% saying "yes" and 50% saying "no."
Our second survey question, asking if such a Category 6 specification should be limited to utp copper communications cable operating above the Category 5 performance limit, drew a strong positive response (43%) and almost no negative response (3%).
Our third question asked if a shielded or screened twisted-pair (stp/sctp) solution would be preferable to specifying utp as the Category 6 medium. Even though shielding is a popular cabling technique in Europe, only 20% of our respondents preferred it over utp, while fully 50% said they did not prefer it over utp.
Asked if they thought an alternative cabling medium should be substituted for Category 5 utp cable operating above the Category 5 limit, a third of the respondents said "yes," while a bit over one-quarter (27%) said "no." Polled about a possible alternative to utp copper wire for high-speed premises applications, one-third of the respondents favored multimode optical fiber, 17% went with extended-performance Category 5 utp, and 7% voted for a shielded or screened solution. No one voted for coaxial cable, although one respondent suggested that a hybrid copper-fiber cabling solution be considered.
As is often the case with surveys, the comments written on the survey forms are often as interesting as the results of the survey itself, and that was certainly the case with our Category 6 survey.
The split over the need for a Category 6 utp standard, for instance, is mirrored in these two comments. "In order to provide a copper-based solution in the horizontal," says Alan McFarland, structured cabling systems engineer with Anixter (Houston, TX), "the need for a higher-performance cable is immediate and widespread. The cable industry must gain a foothold on the technology curve with standards exceeding network capabilities available in today`s marketplace." Michael Finn, vice president of sales for tms (Campbell, CA), has a different perspective, however. "The ink is not dry on most 15-year warranty contracts," he says, "and we have to tell our customers they need to upgrade. It`s time for fiber to become the medium of choice. The increments with copper are just not big enough to justify."
Nick Turvill, registered communications distribution designer (rcdd), who is manager for premises wiring products at Hubbell Canada Inc. (Pickering, ON), comments that "customers have been led to believe that the category system was going to end at Category 5, and that an installation made to the tia/eia-568a Category 5 standard was going to last for a number of years. To release a Category 6 would cast doubt in the minds of customers, suggesting that manufacturers are controlling this process to make an extra dollar."
Turvill adds that the right way to go with utp would be an enhanced version of Category 5, and that a shielded solution should not be labeled Category 6. Why? Because, he says, "it is automatically assumed that Category 6 is better than Category 5. I feel that utp, stp, and fiber should be offered as different, not better, solutions."
Turvill`s countryman, Doug Mitchell, rcdd, of Camtec Services Ltd. (Ft. Saskatchewan, AB, Canada), feels a high-performance alternative to Category 5 utp cable should be optional, "based upon specific site requirements." He adds, "We will continue to see new forms of signal encoding, which will supply bandwidth-hungry applications, without violating the known electrical barriers our cable infrastructure presents. I suggest that the industry has a good copper cable; the connecting hardware may be the area where we have a lot to gain."
Mitchell concludes that extremely high-bandwidth networking applications, such as file-server farms, interfaces between local-area and wide-area networks (lans/wans), and collapsed backbones, will require optical fiber, "with singlemode soon to become the winner." Slightly lower requirements, such as those found in building and campus backbones, will call for composite multimode-singlemode fiber cables, "with copper an option." From the telecommunications closet to the desktop, Mitchell adds: "I am still strong on Category 5 copper within 90 meters. I can see fiber for extended distances."
A survey respondent from Anixter International Services took exception to the survey question linking shielded cabling solutions with the European Community. "There are several different constructions of shielded cable," he (or she) said, "and different countries in Europe use different cabling systems. Shielded cable is popular mainly in France. There is some in Germany, but England, Spain, Italy, and other countries are less likely to use shielded cable. The shielded cables used have several constructions--100-ohm overall foil shield to 120-ohm overall foil shield, and also constructions with individual foil shield by pair and an overall braid shield."
A resounding "no" vote to Category 6 was cast by the president of a cable installation group that also manufactures fiber-optic jumpers. William M. Rowe of Integrated Communications Inc. (Hartfield, VA), says, "In 1991, Category 5 cabling and hardware were standardized by eia/tia-568, and this was to be the standard for the next 15 years. Here we are in 1997 talking about enhanced Category 5 at 300 megahertz and a Category 6. Where will it all end?"
Rowe feels that for many years only larger organizations will be likely to require capabilities greater than those provided by Category 5 cable. "It appears that, with a decrease in overall costs, fiber-to-the-desk is a viable alternative to creating a new standard. Consider that fiber has virtually replaced copper in high-density backbones and long-haul cabling."
Several respondents to the survey pointed out that its wording was incorrect concerning the performance limit of Category 5 cable. The proper terminology would have been to refer to a 100-megahertz versus a 100-megabit-per-second limit (see "Megahertz megabits," page 14).