An OTDR is a powerful tool that helps technicians and engineers assess the health of fiber optic cables. OTDR testing analyzes fiber optic cable performance from end to end by testing components along the cable, including connection points, bends, and splices. The main function of an. An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber. Download free OTDR Trainer Software for PCs After you study this page, you can download a free OTDR Trainer to run on your PC. It can verify splice loss, measure length and find faults. It is equipped with a colour touch screen which allows easy operation. Additionally it can record up to 100. 000 measurements and can transmit them via USB Micro-B port to a computer.