3 recommendations and IEC references, when using an OTDR, launch and receive cables must be used to qualify the front-end and far-end connectors of a fiber/link under test. OTDR testing analyzes fiber optic cable performance from end to end by testing components along the cable, including connection points, bends, and splices. What Is an OTDR? What Is an OTDR? An OTDR is a powerful tool that helps technicians and engineers assess the health of fiber optic cables. It can verify splice loss, measure length and find faults. For municipal utilities, which are increasingly building and operating their own fiber optic infrastructures, the professional implementation of OTDR measurements is becoming a decisive success. An Optical Time Domain Reflectometer (OTDR) is a specialized device used to test the integrity of optical fibers.