Long-time and new users are contributing to worldwide deployment growth.
by PATRICK McLAUGHLIN
Shielded twisted-pair cabling systems may or may not ever be recognized by the Institute of Electrical and Electronics Engineers (IEEE: www.ieee.org) 802.3ba Task Force, or any other group, as an approved medium for transporting 40- and 100-Gbit/sec Ethernet traffic (see “Examining shielded cabling for ultra-high-speed transmission,” January 2010, p. 7). But that uncertainty has not derailed users around the globe from deploying shielded systems. Traditionally achieving far deeper penetration in Europe and other parts of the world than in North America, shielded twisted-pair cabling systems continue on that path as North American inroads remain relatively modest.
Mixing and matching
Market-intelligence firm BSRIA (www.bsria.co.uk) recently wrapped up a study on the media being used to support 10-Gbit transmission. BSRIA gathered information on Category 6A, Category 7 and 7A, and multimode fiber systems used for that purpose. In its research the organization found that consultants to structured cabling projects often specify a cabling system as “10-Gig”—meaning it must support 10-Gbit Ethernet—without specifying the cabling type. As a result, multiple combinations of cable and connectivity hardware, such as Category 7 cable with shielded Category 6A connectors, are being used to achieve 10-Gig application support. Overall BSRIA reports that worldwide approximately 80% of the systems deployed to support 10-Gig are unshielded and 20% are shielded.
BSRIA’s research also indicated that in general Category 6A systems are taking market share from Category 6, not from Category 7 or 7A. The only certain media-type statement that can be made about that statistic is that Category 7 and 7A systems are shielded; Category 6 and 6A systems can be either shielded or unshielded. Regardless, 6A’s taking market share from 6 indicates a level of stability for Category 7 and 7A systems where they are installed. In fact, BSRIA reported that some users, particularly in Germany and Sweden, are putting in place Category 7A cabling systems in preparation for future 40-Gbit transmission speeds. BSRIA says that in the time period 2008-2011, Category 7 and 7A products will enjoy double-digit compound annual growth rates. Overall though, BSRIA says the global trend is to opt for Category 6A systems, shielded or unshielded, due primarily to users’ familiarity with and preference for the 8-position, 8-contract RJ-45-style connector.
Bob Weiland, senior national product manager with Graybar (www.graybar.com), reports that some buying trends in the United States have echoed those that BSRIA reports. Comparing 2009 to 2008 figures, he says, “Shielded Category 6 dropped off in year-over-year quantity but shielded Category 6A almost doubled in volume.” Overall, he says, “Shielded is still not reaching into the North American market, representing less than 1% of overall premises cable shipments. Concerns remain about the cost and installation compared to UTP cable.”
Weiland points out that with shielded representing such a small percentage of overall volume shipments, year-to-year variances like Category 6 falling and Category 6A doubling can hinge on a handful of major contracts, such as with a government entity. Nonetheless, he says customers’ interest level in shielded cabling has been on the rise. “Without question, shielded has not been as popular in the North American market as it has been elsewhere. But it’s been talked about more and more. We’ve seen more internal interaction with our field personnel and customers. There has been more interest in it and more discussion of it.”
Making the case
One cable manufacturer that has been promoting the use of shielded cabling is Siemon (www.siemon.com). Last month the company launched on its Web site an online educational resource specifically devoted to shielded cabling. The one-page resource center aims to direct users to more-in-depth information from the company’s library. The online resource center covers topics including market drivers, system performance, installation and termination practices, and grounding and bonding.
Tyco Electronics’ AMP Netconnect business (www.ampnetconnect.com) has also been an advocate of using shielded twisted-pair cabling systems for transmission speeds of 10 Gbits/sec and higher. Recently the company publicized a Category 7 installation project that may exemplify the global barometer for shielded cabling: Category 7 was used in Duke University Medical School—not the one in North Carolina, USA, but rather the one in Singapore.
The National University of Singapore now offers Duke University graduate-level medical education, AMP Netconnect reports, and the medical institution chose the company’s Category 7 cabling for its infrastructure. “Duke-UNS required high speeds within building network services in order to serve a new computational biology/genomics facility and also to provide a backbone for routing audio/video/desktop displays to a central AV control and recording system,” AMP Netconnect explained. “Building around a 1-Gbit/sec backbone would provide little expansion over the near term,” the company continued. “Duke-NUS selected a 10-Gbit/sec backbone with Category 7 cable from the backbone to office locations, providing the potential for 10-Gbit/sec to the desktop in the future.”
The medical school contracted with a consultant to evaluate structured cabling infrastructure systems that would support the building’s requirements for a period of at least 10 years. The consultant specified media types—fiber and shielded Category 7 twisted-pair copper from AMP Netconnect. After a two-year construction project the building was completed in November 2008.
Zx Ng, the project manager who oversaw the Duke-NUS installation, recalls, “This whole installation was challenging. AMP-Twist 7AS Cat 7A jacks were new for my team but with the AMP Netconnect SL termination tool we were able to significantly reduce termination time and ensure a high level of consistency over the more than 6,000 connections.”
Ease of use
Ng’s reference to a specific termination tool that helped his crews’ efficiency is indicative of shielded cabling system providers’ efforts to combat the notion—justified or not—that shielded cabling is more difficult to work with than unshielded. One piece of information on Siemon’s Web site shows statistics on how quickly cables can be terminated to its brand of shielded Category 6A connector. Another makes the case for a shielded cable’s construction being less sensitive to installation practices than that of UTP cable. It says, in part, “Unlike shielded systems, Category 6A UTP systems rely solely on uncompromised cable geometry to maintain alien crosstalk performance and, if subjected to poor installation practices and substandard MAC [moves, adds, changes] work, are likely to show degraded alien crosstalk performance.”
The market-share success of shielded cabling systems in North America may depend on the mindshare success it gains with users.
Patrick McLaughlin is chief editor of Cabling Installation & Maintenance.