For local area networks that do not require certification, qualification (or performance) testing is a less expensive option for contractors to test that an installation complies with component manufacturer standards and will perform to specifications.
Ideal Networks has shifted to the term “performance testing,” while Fluke Networks identifies the process as “qualification testing.” Either way, this testing isn’t limited to data and communications; it also applies to other structured wiring components.
“Testing and documenting the installation of residential communications cabling can no longer be an afterthought,” said Dan Payerle Barrera, global product manager for Ideal Networks, an Ideal Industries company, Sycamore, Ill. “Access to reliable, high-bandwidth data connections is as important in a residence as any other utility.”
These days, the line separating voice/data and security, alarm or access control systems is becoming increasingly blurry.
“Virtually all of these systems have or are in the process of migrating to ethernet/IP and are serviced by category 5e or better cabling,” Barrera said. “For this reason, a data performance tester can be used to test the physical integrity and data-handling capabilities of the cabling regardless of application. While two- or four-conductor cables for alarm and access control can be tested with a simple VDV tester, the advantage of a proper performance test of the project can be documented with very little extra time or effort, and the advantages that come with having the documentation available cannot be underestimated if a dispute about the installation arises.”
Mark Mullins, field marketing manager, Fluke Networks, Everett, Wash., said qualification testers are perfect for network support staff who need to know if a cabling plant can support a current networking technology.
“Qualification testers also help technicians debug problems such as broken or damaged cables, saving time and user downtime,” Mullins said. “Qualification testers can indicate whether a cabling link will support a specific networking technology, such as gigabit ethernet. This is in contrast to a certification tester, which will indicate if a link meets a specific cabling standard, such as Cat 5e.”
Barrera said the primary factors driving when and how Ideal Networks’ customers test installations are warranty programs, end-user/designer requirements, and their own business practices.
“Interestingly, most contractors are testing and documenting installations for their own needs more than at the request of their customers in all but large commercial or civil projects,” he said. “Proving the performance of the cabling/network with a field tester provides contractors security and peace of mind should questions arise after the project is complete. They want to have documentation that eliminates any questions that the materials or workmanship do not meet expectations. Contractors cannot afford to let projects go untested even when the customer is not asking for test reports.”
Besides the data-carrying aspect of these systems, Barerra said contractors also should consider how power over ethernet (PoE) is being deployed for CCTV cameras, sensors, access control, signage, A/V and any number of other devices.
“PoE is becoming mission-critical, and a data transmission tester that can verify PoE operation is just as necessary to a low-voltage/network technician as a volt meter is to an electrician,” Barrera said. “The very first step in troubleshooting PoE network devices is ensuring that power is available and that [the] poor quality of [an] excessively long cable isn’t causing power to drop to a point that prevents devices from operating properly.”
[SB]Barrera said the term “qualification testing” appears in the TIA-570 standards for residential cabling, though there is no definition about what a qualification test entails.
“It is left to the manufacturer of the tester to determine what is tested and how to report it,” he said. “This is very contrary to the TIA-568 series of standards that specify exactly what and how cabling is tested for non-residential installations.”
Standards for qualification testing most commonly are developed by the Institute of Electrical and Electronic Engineers (IEEE). This includes standards such as 10BASE-T, 100BASE-TX and 1000BASE-T.
Ideal Networks uses the IEEE 802.3ab standard for gigabit ethernet as the guideline for data transmission testers, which defines the allowable bit/frame loss percentage to have a passing link.
“By using this standard, there is no arbitrary pass/fail limit,” Barrera said. “The testers simply send a specified amount of data through the cable or active network link and measure errors reporting the ratio and pass/fail results per the IEEE standard.”
Qualification testing is valuable for security, alarm and control components of structured wiring systems because more of these systems are moving to standard network technologies and the same rules apply.
“Residential networks aren’t nearly so likely to be mission-critical as those in commercial settings,” Mullins said. “Further, most homeowners aren’t concerned about performance decades into the future. For those reasons, qualification can be an attractive alternative to more expensive certification.”
He said that qualification testers should include troubleshooting features such as a time-domain reflectometer (TDR), which can indicate the distance to a fault. Another useful feature enables remote identifiers with unique indicators to be attached to patch panels or wall jacks and the tester attached to the far end to identify which cable goes where. Another method is for the tester to put a signal on the cable that can be identified using a tone probe.
“A newer approach to qualification testing is for the tester to send network traffic across the link rather than the older approach of measuring the electrical characteristics of the cable,” Mullins said. “While this new approach is simpler and can provide a lower cost product, it is not as thorough as the older approach because of the wide variation in the characteristics of transmitting/receiving chipsets. However, while these testers prove that they can communicate without errors across the link, they don’t guarantee that any randomly chosen pair of compliant transmitters and receivers will do so.”
Because network technologies are designed to work in the presence of errors, they can operate over cabling that is not up to the task—but they will operate poorly. Qualification testers can help address this difficult-to-diagnose problem.