OTDR can used to test single-mode wavelengths of 1310nm, 1550nm, 1490nm, 1625nm and 1650nm, multi-mode wavelengths of 850nm and 1300nm as well as customized special wavelengths. It provides multiple optional modules, such as single wavelength, multi-wavelength and online test. With the maximum dynamic range of up to 50dB, the device can be used for remote multi-branch communication network test. It's designed with a minimum event dead zone of 0.5m which makes the near connection easy to be supervised, and the lowest sampling resolution of 2.5cm which enables it to locate the event point accurately. Additionally, the device is also designed with multiple convenient functional options, such as stable light source, optical power meter, visible red-light source and fiber end face inspection tester.