Certification testing that a network meets industry standards is an essential step in installing voice/data/video (VDV) systems in commercial buildings. The process identifies cable faults and other problems that could cause network failure and require costly repairs.
Certification often is thought to be necessary for high-speed data and voice networks only, but it is not limited to that.
“As building automation systems converge, network cabling will support more than just voice and data communications systems,” said Harley B. Lang III, marketing manager for cabling certifications, Fluke Networks (www.flukenetworks.com). “Cabling that is certified to industry-performance standards also can be relied on to support security, alarm and control systems.”
The versatility of cabling has introduced a complexity to the process, as each of these building systems have different requirements.
“But the beauty of industry standards for structured cabling is that, if cabling is designed, installed and certified, it is documented that an application will run on the type of cabling that it is specified to,” Lang said.
Simply put, there are no basic certification tests.
“For example,” Lang said, “a certification tester must run over 89,000 frequency-based calculations in order to certify a link to be Category 6. But the good news is that today’s best certification testers will do it all with the press of a button in less than 10 seconds.”
If a system is specified to run over cabling rated to an industry standard (such as Cat 5e, 6 or 6a), a certification tester is needed to ensure the cabling links meet the requirements, Lang said.
To accomplish certification, trained technicians depend on accurate, reliable certification-testing equipment. Specifically, what testers are necessary to certify a project depends on the types of cable in the network.
The following are basic certification tools for testing copper cabling:
• Wire mapper with multiple remotes to measure distance to open short circuit
• Certification device to prove the installation is standards-compliant (necessary for filing warranties)
The following are essential tools for testing fiber optic cabling:
• Visual fault locator for simple polarity and breaks in cable
• Power meter and light source for simple verification that the link will not exhibit excessive optical loss
• Certification device that can measure length and optical loss (necessary for filing warranties)
Lang said some verification testers may be useful during the installation and after service activation. While these testers will not certify the cabling, they can help eliminate basic problems, such as twisted-pair wiremap failures or fiber end-face contamination.
Although copper continues to dominate most enterprise cabling infrastructure, fiber is becoming increasingly prevalent. To be most cost-effective, Lang said, it is helpful for contractors and installers to be able to use their existing copper certification tools to certify fiber cabling.
“A single user interface,” he said, “increases efficiency, and allows contractors to respond to the growing fiber business with minimal training costs. Fluke Networks’ DTX cable analyzer is a cabling certification instrument for both copper and fiber. Simply by using the proper fiber modules and attachments, the DTX is transformed into a fully functional fiber loss-length tester and OTDR [optical time-domain reflectometer] that accurately and precisely tests according to the most current industry standards.”
Industry standards and customer requirements drive changes in certification-testing equipment.
“In the last year,” Lang said, “we have begun to see real adoption of 10G technology (that we have been talking about for over 8 years) starting to be deployed in data centers. Server consolidation is driving a lot of this, placing greater emphasis on the reliability of the physical infrastructure. Also, the third generation of electronic equipment and cable and connecting hardware has made it more cost effective to deploy 10 Gbps [gigabits per second] in enterprise networks, even beyond the data centers.”
Alien crosstalk (AXT) is a prominent concern in the successful operation for 10G Ethernet, Lang said, and in the past two years, AXT testing has become more prevalent. AXT certification for 10G Base-T should include sample testing of some links in a bundle to verify compliance with AXT test parameters. New augmented cables define a higher level of performance for the cabling performance as well as for the AXT characteristics of a cabling system.
“From a fiber testing standpoint,” Lang said, “we’ve had a 10 Gbps standard and been successfully performing cabling certification for many years, but there have been several refinements to how certain testing should be performed. One example is the improvement of launch condition requirements for compliant light sources for fiber testing. The TIA and IEC standards bodies now both have documents that describe the requirements for encircled flux (EF), specifically IEC 61280-4-1 Ed.2.0, of which the latter will likely be adopted as TIA-526-14-B, Multimode Cable Plant Attenuation Measurements. This will make testing more consistent from one fiber tester to another, whether they are from the same product line or manufacturer or from competitors in the industry. There has also been some work to clarify sampling methods for AXT testing, which will simplify this type of field testing.”
Now that 10 Gbps Ethernet over twisted-pair is a reality, Lang said technologists are starting to look at what the next generation of technologies might bring. To that point, in 2010, there was approval of a 40G and 100G Ethernet standard over fiber and short distances over twinaxial cable.
As with 10G, some in the industry want to drive the costs of these speeds down with a twisted-pair copper solution.
“But, to date, there is no project in IEEE to consider it. Once there is agreement for a project by IEEE, effort could begin to try to figure out how an eventual standard might look. The technology, test parameters and frequency must be defined before we can begin to suppose how it will need to be field-tested,” Lang said.
In addition to Fluke Networks, other major manufacturers of certification testers include Greenlee Textron and Ideal Industries.
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at firstname.lastname@example.org.