OTDR adopts 4.3-inch capacitive touchscreen. lt integrates 12 functions, such as auto OTDR, expertOTDR, event map, OPM, RJ45 cable tracker, and "computerlevel" file management to meet various test requirements indifferent occasions. OTDR has a maximum dynamic range of26dB, 8G memory, and can store more than 200,000 curves; itis equipped with 4000mAh high-density polymer lithiumbattery, intelligent power saving management, measuringtime of more than 8 hours, and supporting power supply andcharging of the power bank.NK4000 series are used to measure the length, loss, connec-tion quality and other parameters of optical fiber. lt is widelyused in FITX, secondary backbone network engineeringconstruction, maintenance and emergency repair test, andproduction measurement of opticalfiber and cable.