First of all, it is necessary to understand how to use the instrument and how to use the instrument, which is helpful for accurate measurement.

1. Set the parameters of OTDR. When using the OTDR test, you must first set the instrument parameters, the most important of which is to set the refractive index and test wavelength of the test fiber. Only when the basic parameters of the test instrument are set accurately can conditions be created for accurate testing.

2. Use the magnifying function of the instrument. With the magnification function of OTDR, the light standard can be set at the corresponding inflection point. With the magnification function key, the figure can be magnified to 25m/grid, so that more accurate test results with a resolution of less than 1m can be obtained.

3. Adjust the accurate test range. For different test range files, the distance resolution of OTDR test is different. When measuring optical fiber obstacle points, the closest test range file that is larger than the measured distance should be selected to make full use of the instrument's own accuracy for measurement.

Secondly, accurate and completed original documents shall be established during maintenance and management. These accurately completed optical cable circuit files are the basic basis for fault measurement and location. Therefore, we should not neglect in the maintenance and management process, and should establish true, reliable and complete line data.

During the optical cable connection monitoring, the cumulative length of optical fiber from the test end to each joint point and the total attenuation value of the optical fiber in the trunk section are recorded, and the model of the test instrument and the set value of the refractive index during the test are also registered. Accurately record the remaining optical cables. Record the reserved length of optical cable reels at each joint pit, special section, S-shaped laying, entrance room, etc., and the reserved length of optical cable reels at joint boxes, terminal boxes, ODF racks, etc. in detail, so that they can be deducted when converting the route length of fault points.