OTDR Optical Fiber Launch Cable Singlemode 9/125um 1km OS2 SC/APCSC UPC Connector Item Type: OTDR Optical Fiber Launch CableSC/APC-SC/APC stands for connector OS2 stands for single mode Testing, Inspection and Positioning:  How e Fiber Extension Cords to Generate Baseline Traces:  1. Use the OTDR optical fiber extension cable as the launching cable: Connect the OTDR optical fiber extension cable between the OTDR and the optical fiber line under test. This will enable you to measure the loss of the near-end connection. 2. Use the OTDR optical fiber extension cord as a receiving optical cable: Connect the optical fiber extension cord to the remote connection of the optical fiber line under test. This will allow you to measure the loss of the remote connection. 3. By using the optical fiber extension cable as the transmitting and receiving optical cable, you can easily measure the total insertion loss of the optical fiber line under test.