The OTD-1315 is a precision handheld optical time domain reflectometer for ease of use and transport. An OTDR is used for fiber installation verification, distance measurement, trouble- shooting for damaged fiber, optical link loss measurement and for testing optical splice locations and quality. An OTDR works on the radar principle where an optical signal is sent down the fiber and then it measures the time it takes for it to be reflected back to the instrument and it converts this time to distance.