Shielded cabling making a market re-emergence

Feb. 1, 2007
For decades, the use of shielded cabling systems in LANs within North America has been an oddity...

For decades, the use of shielded cabling systems in LANs within North America has been an oddity, reserved either for applications that never upgraded from the old IBM Type 1 system installed in the 1980s or for those facing extreme external noise sources that adversely affected signal transmission. Today, the specification of a shielded system for a LAN is no longer so rare, as several cabling vendors report increased demand for their shielded products among North American users.

Hitachi Cable Manchester ( recently reported that demand for its shielded Category 5e and Category 6 products has “skyrocketed” over the course of several months; sales of the company’s Category 5e and Category 6 products for the third quarter of 2006 were up more than 100% over the same period in 2005. And product engineers within Tyco Electronics’ AMP Netconnect group ( have stated flatly that foiled twisted-pair cabling-a cable construction that includes a single foil shield over four otherwise unshielded twisted pairs-is a more viable alternative than unshielded twisted pair for running the latest twisted-pair-flavored Ethernet protocol, 10GBase-T. (See “Why shielded twisted-pair matters for 10GBase-T,” Cabling Installation & Maintenance, December 2006, p. 13)

The 10-Gigabit Ethernet advantage

“We’re finding that more and more companies are choosing our shielded products due to their inherent immunity from radio-frequency interference and electromagnetic interference,” says Hitachi Cable Manchester’s senior vice president Lynne Humenik. “They are also choosing our Category 6 ScTP [screened twisted-pair, an alternate name for foiled twisted-pair] because it supports 10-Gigabit Ethernet to 100 meters. As 10-Gigabit Ethernet electronics become more prevalent in the marketplace, we can expect demand for our Category 6 ScTP to continue to increase.”

AMP Netconnect recently introduced a half-day training course aimed at design and installation contractors who are certified to install the manufacturer’s cabling systems. The course specifically covers the use of shielded twisted-pair cabling systems for 10-Gigabit Ethernet applications.

“The objective is to educate certified contractors on the superior performance capabilities of shielded cabling, promote an understanding of how to specify, bid, properly install and test a shielded system, and verify the statistics that make shielded cabling a cost-competitive alternative to 10-GbE UTP systems,” AMP Netconnect said in a release announcing the new course.

Added Wally Harvan, product training manager with the company, “With better Shannon Capacity, alien crosstalk, and EMI/RFI performance, shielded solutions are gaining more recognition. Still, there is a need to educate the industry about the advantages of using shielded cabling, including its smaller diameter that requires less space, its simplified installation due to innovations in connector technology, and elimination of time-consuming alien crosstalk testing.”

The apparent re-emergence of shielded cabling results directly from the efforts from cable and connector manufacturers to develop working systems that successfully transmit 10GBase-T signals. Although 10GBase-T network switches are still probably months away from being available on the market, cabling vendors have for some time known the performance parameters their systems will have to meet to handle 10GBase-T.

The most critical parameter in 10GBase-T transmission, and a topic that has been a prominent point of discussion in this and other publications, is alien crosstalk-the electrical phenomenon that occurs when a signal from one cable acts as interfering noise to a signal running on another cable. It is a reality in twisted-pair copper LAN cabling because the cables typically are tightly bundled as they traverse the horizontal portion of the network, from the telecommunications room in which connecting hardware is housed to the user’s work area. The tightest bundles present a worst-case scenario of six cables around one, meaning the center cable could be adversely affected by the combined alien crosstalk emanating from the six surrounding cables.

Despite these challenges, cabling vendors have developed pre-standard Category 6A unshielded twisted-pair systems that meet the necessary parameters to transmit 10GBase-T (see related story, “Cabling, silicon vendors demonstrate 10GBase-T capability”). In addition to 23-AWG conductors (previous-generation UTP cables contained 24-AWG wires), Category 6A UTP cables include separators and/or heavy outer sheaths, both designed primarily so that when multiple cables are bundles or grouped together, each cable’s conductors will be separated from every other cable’s conductors by as much space as possible. As a result, Category 6A UTP cables are larger in diameter than Category 6 or earlier-generation UTP constructions.

Thinking smaller

The increased cable size has been a contributing factor in the growing interest in shielded cabling systems. But manufacturers and supporters (sometimes one and the same) of UTP cable say the days of fire-hose-thick Category 6A cable will come to a close. Prompted by pressure from vendors in the networking industry-primarily those that will offer 10GBase-T network switches-cable manufacturers have been busy in their research-and-design labs developing smaller-diameter UTP cables that meet the pending Category 6A performance specifications. No manufacturer has come to market with such a cable yet, but it is entirely possible the industry will see smaller cables meeting the 6A specifications before it actually sees the 6A specs.

Cabling Installation & Maintenance continues to follow the technological and market forces that shape the dynamics of shielded cabling’s apparent re-emergence in the LAN market. On January 17, the publication hosted a Web-delivered seminar on the topic of shielded twisted-pair cabling systems. The seminar, which can be viewed free of charge at the Web site, also included information about the current state of UTP technology and reasons for the surging interest in shielded systems.

Short runs…

DALLAS, TX-This month, Data Drive Thru ( plans to release what it says is the only USB 2.0-certified cable that is small enough to be used in USB-retractable cable-based products. According to the company, the new cable technology reduces electromagnetic wave leakage found in other flat-cable products that can be harmful to the user, environment, and computer and its components. Currently available miniature flat cables have a surrounding static field that may cause interference on the data transmission and result in the transmission to stop abruptly. “Anyone who has experienced data loss or device damage using flat USB mini cables currently found on the shelves of almost every computer retailer in the country has exposed themselves to potentially harmful EMI waves,” claims DJ Reber, technical director for Data Drive Thru. “We believe this new patent-pending cable is the defining architecture for mini-USB 2.0 cables.”

BINYAMINA, ISRAEL-Hermon Laboratories ( has developed new solutions for VoIP and SIP (session initiation protocol) conformance testing, which are available as add-ons to the company’s TCA 8200 telecom conformance analyzer. According to the company, the TCA 8200 system provides the only comprehensive solution for testing compliance with all major telecom standards worldwide. The VoIP add-on complies with TIA/EIA-810, and is designed to enable complete testing of transmission among analog, digital, and VoIP in any combination. The company says the solution provides TIMS (telecom interface modules) and voice-quality testing and Echo cancellation, as well as acoustic testing of VoIP telephones with optional VQT (PESQ). With the addition of the VoIP and SIP testing solutions, says Hermon Laboratories CEO Alex Usoskin, “the TCA 8200 makes it easier and faster than ever to develop and test new VoIP products for international compliance. For our worldwide customer base, this means they can get to market faster, regardless of the geographic spread of their market.”

BOLINGBROOK, IL-Windy City Wire ( recently moved into a new 115,000-square-foot facility here. The low-voltage wire and cable company has recently experienced substantial growth, and anticipated hiring up to 10 additional sales professionals. A 50-person training room will be used for new employees as well as for customers who want to learn how to use the company’s products. In operation since 1994, Windy City Wire’s flagship product is SmartWire, which is a low-voltage cable that has the qualities of a tape measure, tester, toner, and a label maker. The company serves security, access control, CCTV, temperature control, fire alarm, and home automation contractors.

RICHMOND, IN-Belden ( is phasing out its X-Mark branded line of cable management products, and will remarket them as Belden Cable Management Solutions. Peter Sheehan, president of Belden Americas, says the rebranding of X-Mark products, which have been part of the CDT family for the past decade, is part of Belden’s strategy to unify its entire portfolio of signal transmission products under the Belden brand. The entire X-Mark sales organization will now be unified under Belden, but X-Mark customers may continue to work with their existing customer service representatives. “What this will do is provide our customers with a convenient single source for all of their cabling needs, as well as their cable management requirements,” says Sheehan.

WATERTOWN, CT-Siemon ( is teaming with Communications Supply Corp.’s ( Secure(it) initiative, which is focused on developing products and solutions for high-assurance facilities, secure network deployments, and information assurance applications. The initiative is closely aligned with the Department of Defense’s Defense-in-Depth strategy and the increased focus on information assurance and cyber-security across government and commercial IT. Siemon has traditionally dedicated a significant portion of its R&D efforts to create cabling solutions that address the expanding market need for high-assurance networks; for the Secure(it) initiative, it will focus on its Category 7/Class F TERA shielded copper solution, the 10G 6A F/UTP screened Category 6A solution, and the MapIT infrastructure management solution.

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