The continuous development of economy promotes the constant updating and upgrading of the information age, the transmission rate and capacity of copper cables can no longer meet the needs of the people, so the cable market ushered in an unprecedented development. Nowadays with the support of national policy, fiber optic cable lines have been laid and used in large numbers. The related technology of optical fiber communication has been taken seriously by people for their repeated studies. Their reliability and safety have also drawn more and more attention. Relevant data show that the main reason for about two-thirds or more of optical fiber communication failures is due to fiber optic cable failures. In the optical fiber communication, if encountering the optic fiber to cut off, we consider the optic cable trouble first and take certain positioning measures to it, examine the outside first and then transmit. Externals such as: fiber breakage, power interruption, etc., before testing the transmission equipment. Therefore, how to improve the accuracy of fiber optic cable fault location help to accurately determine the point of failure. The following integrated wiring manufacturers take everyone to find out: to improve the accuracy of cable line fault location method. First of all, to understand how to use the instrument, master instrument use, help to accurately measure. 1, set the OTDR parameters. When using the OTDR test, you must first set the instrument parameters, the most important is to set the refractive index of the test fiber and the test wavelength. Only by accurately setting the basic parameters of the test instrument, in order to create the conditions for accurate testing. 2, using the instrument's amplification. OTDR amplification function can be used to accurately set the cursor on the corresponding inflection point, use the zoom function keys can be enlarged to 25 meters / grid graph, so you can get a resolution of less than 1 meter more accurate test results. 3, adjust the accurate test range file. For different test range files, the distance resolution of the OTDR test is different. When measuring the optical fiber obstacle point, the test range file that is larger than the measured distance and the nearest test range file should be selected so as to make full use of the accuracy of the instrument for measurement. Second, the maintenance and management process should establish accurate and complete the original document information. These accurate completion of the cable line file is the basic basis for fault measurement, positioning. Therefore, the maintenance and management process can not be negligent, we should establish a true, credible, complete line of information. While continuing the monitoring of the optical cable, record the total length of the optical fiber from the test end to each joint point and the total attenuation value of the optical fiber of the relay section, and register the set values ​​of the test instrument model and the refractive index during the test. Accurately record a variety of optical cable remaining. Detailed records of each joint pit, special sections, S-shaped laying, into the room and other places at the cable tray length and the splice box, terminal box, ODF rack and other parts of the optical disk length to be converted in the fault point routing length to be deducted. In addition, the consistency of test conditions should be maintained during the measurement. Obstacle test should try to ensure the consistency of test instrument model, operation method and instrument parameter setting, so that the test results are comparable. Therefore, each test instrument model, test parameter settings have to do a detailed record for later use. Finally, a comprehensive analysis. Obstacle point test requires the operator must have a clear idea and flexible approach to the problem, clear logical thinking wherever they are used. Under normal circumstances, the two ends of the optical fiber cable are two-way fault test, and then combined with the original data analysis, and then ready to determine the specific location of the fault. When the link around the point of failure has no obvious characteristics and the specific site can not be determined, then we can take the measurement method of the nearest junction, excavating at the obstacle point of the preliminary test, and the end station test instrument being in the real-time measurement state.