There are a variety of optical test sets that can be used to ensure quality of service (QoS) on fiber optic networks, but only the Optical Time Domain Reflectometer (OTDR) supports singled ended fiber testing to characterize fibers when measuring total loss, optical return loss. There are a variety of optical test sets that can be used to ensure quality of service (QoS) on fiber optic networks, but only the Optical Time Domain Reflectometer (OTDR) supports singled ended fiber testing to characterize fibers when measuring total loss, optical return loss. 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. An Optical Time Domain Reflectometer (OTDR) is a device that tests the integrity of a fiber cable and is used for the building, certifying, maintaining, and troubleshooting fiber optic systems. Hand-held OTDRs build a virtual image of the fiber optic cable to determine the condition and performance. The FlexScan family of OTDRs automates test setup, shortens test time and simplifies results interpretation - improving efficiency and reducing costs. For the OLT device, the OTDR port can switch between LINE-TX and LINE-RX ports. The Versiv platform includes these features: Operates with DSX CableAnalyzer ™.