Effective fiber testing utilizes advanced tools such as Optical Loss Test Sets (OLTS), Optical Time-Domain Reflectometers (OTDR), and Visual Fault Locators (VFL) to diagnose and correct issues, ensuring optimal network performance. The Contractor tasked to perform testing or splicing on any fiber optic cable will follow these testing standards to fulfill their contractual obligations. And because fiber optic cables carry light instead of electricity, they are not affected by changes in the temperature and can withstand extreme. After fiber optic cables are installed, spliced and terminated, they must be tested. If it's a long outside plant cable with intermediate splices, you will.