... than 1m ultrashort time dead zone Optical Time Domain Reflectometer , OTDR , optical reflectometer main feature1.≤ 1m ultrashort time dead zone ... vfl) and optical power meter function;13.can change otdr light output head type casually, cleaning interface is more ... .applications upgrade online, without returning to the original. AV6413 High-performance Multi-functional Optical Time Domain Reflectometer