Contractors Face Incompatibility Issues in Low-voltage Installations

Prior to the advent of national and international standards, IBM, DEC, Wang, and others created proprietary networking systems. Eventually, Electronics Industry Association/Telecommunications Industry Association (EIA/TIA) and International Standards Organization/ International Electrotechnical Committee (ISO/IEC) stepped in to define performance and installation standards for low-voltage systems, paving the way for an open architecture environment where interoperability and intermatability were givens. That era has culminated in today’s Category 5e standard. Now, as the proposed standards for Category 6 are taking shape, the industry finds itself at a crossroads. Are we returning to the days of proprietary systems that offer little or no compatibility? As we trade the open architecture of the Category 5/5e world for the super-high performance of Category 6 and beyond, installers can no longer safely mix and match products from multiple vendors. Instead, a new generation of proprietary systems is emerging that could lock contractors and end-users into a narrow subset of suppliers for their cabling, infrastructure, and connectivity solutions—with no guarantees that performance criteria will be met. To ensure that end-users get the performance levels they expect from a proposed Category 6 installation, contractors must be aware of several potential trouble spots. Ensuring your Cat 6 solution’s backward compatibility Compatibility issues first come into play when moving up to the proposed speeds of Category 6, which currently requires a much tighter-performing system electrically than Category 5 or Category 5e. In an effort to stay ahead of the game, many vendors are already offering Category 6 solutions by tuning their hardware to the proposed requirements. Because each vendor’s method is a little different, its solution may not be backward compatible with Category 5 or Category 5e systems, as the standard stipulates. Mixing but not matching With Category 6 on the verge of becoming the new standard, it is widely accepted that the RJ-45 modular connector is being pushed to its limits. Therefore, manufacturers are finding proprietary solutions to compensate within the copper unshielded twisted pair (UTP) environment: - Tuning connectors through the use of contact spatial relationships; - Adapting connectors to a variety of printed circuit board solutions; and - Specifying the use of cable media that are tested to perform better with a particular manufacturer’s connectors. The end result is that connectors and cables from multiple vendors may no longer provide the interoperability found in Category 5/5e, even with the RJ-45 plug still in widespread use. Moving beyond Category 6, the emergence of proprietary connector styles could make interoperability improbable, if not impossible. Remembering the infrastructure Another easily overlooked challenge presented by proprietary systems is compatibility with the infrastructure system, which encompasses surface raceway, modular furniture, floor boxes, in-floor distribution systems, etc. Manufacturers of these infrastructure components have developed proprietary low-voltage mounting hardware. Therefore, if an electrical contractor selects a particular raceway system, but the low-voltage installer chooses connectivity products from another manufacturer, several resulting scenarios could compromise the final channel performance: - Cables routing too close to line voltages; - Inadequate cable capacity; and - Limited space allowances for proper cable bend radii. The choice of a connectivity solution can also substantially impact the desired infrastructure system’s final cost because proprietary mounting plates may be required. Whether an electrical contractor is completing the entire installation or only a part of it, the key to creating a compatible system is forethought and communication. If all installers on a job collectively address infrastructure, cabling, and connectivity choices on the front end, they will save time and money, and help deliver the performance the end-user expects. Adhering to standards-compliant installation practices Another job component that can cause performance problems involves installation practices. To ensure performance to the proposed Category 6 standards, an electrical contractor should rigidly adhere to installation practices outlined by the standard, with emphasis on three primary issues: - Cable pull pressure: To avoid attenuation problems, pull pressure cannot exceed 25 pounds. - Bend radius: Category 6 performance requires a minimum bend radius of four times the external nominal diameter of the cable being used. - Termination: The cable jacket should be stripped back as little as possible to complete the termination, with untwisting of pairs limited to no more than 1/2 inch from the last twist to the termination point. Selecting patch and line cords for the system A final topic of concern involves patch and line cord selection. This is not a time for contractors to scrimp by using field-terminated patch/line cords. It is essential to use the Category 6 patch/line cords provided by the connectivity vendor selected. To ensure conformity to the standard, contractors should also—whenever possible—perform a link and a channel test for each node being installed. Contractors beware Although contractors are virtually powerless to reverse the industry shift to proprietary systems, they can rise above the confusion by remaining aware of compatibility pitfalls and by keeping communication lines open among installers and end-users. In other words, what you don’t know can hurt you and your customers. Ultimately, rigorous link and channel testing, combined with plenty of product research, should enable contractors and other installers to deliver the high-performance systems that today’s end-users demand. Chase is marketing manager for commercial wire management at Thomas & Betts Corporation in Memphis, Tenn. He can be reached at (901) 252-5000 or via e-mail at Cochran, RCDD, is technical marketing manager at Thomas & Betts Corporation in Memphis, Tenn. He can be reached at (901) 252-5000 or via e-mail at

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