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Communications can be a vital element of any cable installation in which two or more people are working together, especially when the two ends of the permanent cable runs are a long distance apart, as on a fiber-optic network. Some test sets address this problem by incorporating voice communication devices into the power meter and light source, using the tested cable to carry the signals.

Multifunction Cable Testers

The most heavily marketed cable testing tools available today are the multifunction cable scanners, sometimes called certification tools. These are devices that are available for both copper and fiber-optic networks. They perform a series of tests on a cable run, compare the results against either preprogrammed standards or parameters that you supply, and display the outcome as a series of pass or fail ratings. Most of these units perform the basic tests called for by the most commonly used standards—such as wire mapping, length, attenuation, and NEXT for copper cables—and optical power and signal loss for fiber-optic. Many of the copper cable scanners also go beyond the basics to perform a comprehensive battery of tests, including propagation delay, delay skew, PS-NEXT, ELFNEXT, PS-ELFNEXT, and return loss.

The primary advantage of this type of device is that anyone can use it. You simply connect the unit to a cable, press a button, and read off the results after a few seconds. Many units can store the results of many individual tests in memory, download them to a PC, or output them directly to a printer.

This primary advantage, however, is also the primary disadvantage of this type of device. The implication behind these products is that you don’t really have to understand the tests being performed, the results of those tests, or the cabling standards used to evaluate them. The interface insulates you from the raw data, and you are supposed to trust the manufacturer implicitly and believe that a series of pass ratings means that your cables are installed correctly and functioning properly.

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