An optical loss test set integrates both a light source and a power meter into the same unit, a pair of these is often used for bi-directional measurements on singlemode systems. Walk into any fiber test gear catalog and you will see "LSPM kit" listed alongside power meters, light sources, and OTDRs. They provide the data necessary to quantify signal loss and pinpoint issues that could impact network performance. Its test process can be divided into two stages. There is a difference in device loss between these. If using an optical loss test set (OLTS) containing a power meter and light source in one box, simply swap the connections after the test is run at the patch panel or fiber distribution center, being careful to maintain the mated connections to the test equipment (see Figure 5 and 6). In this video, you will learn one and two-patch cord reference testing using the FIS Power Meter and Light Source.
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