An OTDR is an optoelectronic instrument used to characterize optical fibers by emitting light pulses and analyzing the backscattered signals. Think of it as a "radar for fiber optics"—it detects faults, splices, bends, and losses along a cable, providing a visual trace of the. This OTDR Fault Finder has easy operation, long battery life, multiple wavelengths, FTTX testing. Choose Your optimal dynamic range. This product is already in your quote request list. 6 Optical Time Domain Reflectometers (OTDR) from MELONTEL meet your specification. 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.