Hi there!
This time, I will share with you a case about the FD tool that cannot measure the 138 km optical cable distance.
Problem Description:
When the user uses the FD tool to monitor the quality of the optical fiber, they find that it cannot test the length of 138KM, and the user does not understand.
Handling process:
The FIU+unidirectional test mode is used onsite. In this mode, only 70km of the online model can be tested, and 80km of the offline model can be tested. Therefore, the FIU unidirectional detection mode cannot meet the scenario requirements and needs to be changed to the FIU+bidirectional detection mode. Bidirectional mode: 150 km
When the FIU+bidirectional detection mode is used, the expected result is achieved. The problem is solved.
Root Cause:
The FD test mode is incorrect.
Solution：
Change the test mode to the bidirectional mode of the FIU+bidirectional detection mode.
Configuration procedure:
In the table, click a detected fiber and set monitoring parameters.
1. If both the source and sink NEs of the fiber to be detected have detection ports, you can select Bidirectional Detection in the Signal Flow Diagram dialog box that is displayed.
You can select the source and sink boards for fiber detection at the same time and start bidirectional detection. The bidirectional detection results can be merged. If you do not select Bidirectional Detection, the system performs unidirectional detection only through the board at the source end by default.
2. Optional: If Bidirectional Detection is not selected, when SFIU/DAPXF ((functioning as the SFIU))/OLSPA/OLSPB intended for OSN 8800/6800/3800/9800/9600 (in single-fiber bidirectional networking) or DSFIU, WSMD9XF (functioning as the SFIU) intended for OSN 1800 (supporting single-fiber bidirectional detection) is used, select a board for fiber detection from the source NE or sink NE in the displayed Signal Flow Diagram area. In other detection scenarios, no detection port needs to be selected.
3. Optional: If Bidirectional Detection is selected, you can deselect Use The Same Parameters in the Manual Detection area on the right if the detection boards at the source and sink ends use different detection modes and parameters for bidirectional detection. If you select Use The Same Parameters, the detection boards at the source and sink ends use the same detection mode and parameters by default for bidirectional detection.
4. In the Detection Mode area on the right, set the detection mode and parameters.
NOTE：
In this scenario, single-fiber bidirectional OTDR detection (manual mode only) can be performed on a fiber with OSC boards, however, detection cannot be performed simultaneously at both ends. (Cause: The lights for detecting both ends of fiber will affect each other and cause an OTDR curve abnormality.)
In the case of bidirectional detection, you need to set the detection modes and parameters for the source and sink boards. In the case of unidirectional detection, you only need to set the detection mode and parameters for the source board.
Different detection boards support different detection modes and parameters. If the same detection modes and parameters are used for the bidirectional detection, the detection modes and parameters must be supported by detection boards at both sources and sink ends.
That's all, welcome everyone to leave a message and exchange in the comment area!
Thank you！
