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The fundamental problem with this process, however, is that the standards used to assess the test results gathered by the device are not necessarily reliable. Some units claim to certify Category 6 and Category 7 cables, for example, when standards for these cables have not yet been ratified. One must even question the validity of the testers that claim to certify Category 5e cables, since this standard was ratified only recently. When evaluating products like these, it’s important to choose units that are upgradable or manually configurable so that you can keep up with the constantly evolving standards.

This configurability can lead to another problem, however. In many cases, it isn’t difficult to modify the testing parameters of these units to make it easier for a cable to pass muster. For example, simply changing the NVP for a copper cable can make a faulty cable pass the unit’s tests. An unscrupulous contractor can conceivably perform a shoddy installation using

inferior cable and use his own carefully prepared tester to show the client a list of perfect “pass” test results.

As another example, some of the more elaborate (and more expensive) fiber-optic cable testers attempt to simplify the testing process by supplying main and remote units that contain both an integrated light source and semiconductor detector and then by testing at the 850nm and 1,300nm wavelengths simultaneously. This type of device enables you to test the cable in both directions and at both wavelengths simply by connecting the two units to either end of a cable run. There is no need to use reference test cables to swap the units to test the run from each direction or run a separate test for each wavelength.

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