In optical fiber communication, if the optical fiber is interrupted, we first consider the optical cable fault and take certain positioning measures, first check the outside and then go to the transmission. External eg: fiber break, power interruption, etc. Then test the transmission equipment. Therefore, how to improve the accuracy of fault location of optical cable lines is helpful to accurately determine the fault point.

To accurately determine the fault point, we need to use the instrument. Therefore, we need to understand how to use the instrument and master the use of the instrument. The following are the instructions for using the meter:

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

2. Use the magnification function of the instrument. Using the zoom function of the OTDR, the cursor can be accurately positioned on the corresponding inflection point, and the zoom function key can be used to zoom the graph to 25 meters/div, so that more accurate test results with a resolution of less than 1 meter can be obtained.

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 instrument's own accuracy for measurement.

Secondly, accurate and complete original documents should be established during the maintenance and management process. These accurately completed optical cable line files are the basic basis for fault measurement and location. Therefore, the maintenance and management process should not be negligent, and should establish true, credible and complete line information.

When monitoring the optical cable connection, the cumulative length of the optical fiber from the test end to each joint point and the total attenuation value of the optical fiber in the relay 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 various cable residues. Record in detail the length of optical cable reeling at each joint pit, special section, S-shaped laying, room entry, etc., and the optical reeling length of joint boxes, terminal boxes, ODF racks, etc., so as to be deducted when converting the routing length of the fault point.

In addition, the test conditions should be kept consistent during the measurement. During the obstacle test, the consistency of the test instrument model, operation method and instrument parameter setting should be ensured as far as possible, so that the test results are comparable. Therefore, the model of the test instrument and the setting of the test parameters should be recorded in detail each time for future use.