OTDR settings are a balance between dynamic range, acquisition time, spatial resolution and accuracy. Learn to certify, maintain, and troubleshoot your fiber optic systems better with industry-leading OTDR test equipment and procedures. Power on the OTDR and verify the battery is charged and the test display is functioning. Clean and inspect the ends of all fibers under test, launch cables. Download free OTDR Trainer Software for PCs After you study this page, you can download a free OTDR Trainer to run on your PC. The Optical Time Domain Reflectometer (OTDR) is useful for testing the integrity of fiber optic cables.