ONU Frequently Goes Online and Offline(2) - Unmatched Optical Fiber Connectors

SmartAX MA5600T/MA5603T Multi-service Access Module Troubleshooting: ONU Frequently Goes Online and Offline: TC-C6311 An ONT Frequently Goes Online and Offline Because of Unmatched Optical Fiber Connectors

This topic describes how to troubleshoot the fault when the deployed ONT frequently goes online and offline because the optical fiber connectors do not match.

Fault Description

When an ONT is installed in the deployment, the optical path attenuation is -23 dBm, which is within the normal attenuation range. After the optical fibers are connected, the LED of the PON port blinks. In addition, the ONT fails to register with the OLT normally, and the ONT goes online and offline frequently.

Alarm Information

The up and down alarms about the ONT (OT928) are generated on the OLT.

Cause Analysis

l The optical path attenuation is very large.

l The optical fiber connectors are not clean or not connected properly.

Procedure

Step 1 Use an optical power meter to measure the optical path attenuation. It is found that the optical path attenuation is -23 dBm, which is within the normal range of the optical path attenuation.

Step 2 It is suspected that the poor quality of optical signals is caused by the dirty optical fiber connectors of the ONT (OT928). Clean the optical fiber connectors, and remove and then insert the optical fiber connectors again. The fault, however, persists.

Step 3 Replace the ONT with another ONT (OT928) to conduct a test. The fault, however, persists, which indicates that the hardware of the ONT (OT928) is normal.

Step 4 Check the fiber patch cord of the ONT (OT928). It is found that the connector of the fiber patch cord does not match the optical fiber connector of the ONT. Though the connector of the fiber patch cord is square, the color is different. After verification, the optical fiber connectors used in the ONT (OT928) are green, square, and SC/APC.

NOTE

The BOM is 14130252, and the name is Patch Cord, SC/APC-FC/PC, Singlemode-G.652, 3mm, 3m.

Step 5 Replace the fiber patch cord with a correct fiber patch cord (SC/APC-FC/PC). As a result, the LED of the PON port is stable, and the ONT can register with the OLT normally.

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Suggestion and Conclusion

Currently, the type of the fiber patch cord used in the ONT (OT928) is seldom used in China, but is mostly used abroad. Therefore, note that you should use the correct fiber patch cord.

The greatest difference between green and blue fiber patch cords is as follows: The

interconnection section between the fiber patch cord with green connectors and the OT928 is oblique. The interconnection section between the fiber patch cord with blue connectors and the ONT is plane, which can result in 3-6 dBm optical attenuation.

ONU Frequently Goes Online and Offline(1) - Unstable Voltage

SmartAX MA5600T/MA5603T Multi-service Access Module Troubleshooting: ONU Frequently Goes Online and Offline:

The ONU frequently going online and offline failure is a fault in which an ONU connected to a PON port of an OLT frequently goes online and offline and therefore the OLT reports a large number of ONU LOS and ONU signal recovery alarms.

There are several reasons if the ONU frequently goes online and offline, we will tell the detailed on this blog.

1 TC-C6007 An ONU Goes Online and Offline Repeatedly Because of

Unstable Voltage

This topic describes how to troubleshoot the fault when an ONU goes online and offline

repeatedly and alarms that the ONU goes online and offline repeatedly are generated on the OLT because of unstable voltage.

Fault Description

An ONU connected to an OLT in an office goes online and offline repeatedly and irregularly.

Alarm Information

Alarms that the ONU goes online and offline repeatedly are generated on the OLT.

Cause Analysis

l The optical fiber attenuation is very large.

l The hardware of the ONU is faulty.

l The boards on the OLT are faulty.

Procedure

Step 1 Other ONUs connected to the PON port are normal, which indicates that the PON board of the OLT is normal.

Step 2 Use an optical power meter to test the optical fiber attenuation on the ONU side. It is found that the optical fiber attenuation is -20 dB, which is normal. This indicates that the line is normal.

Step 3 Replace the ONU with another ONU. The fault, however, persists, which indicates that the hardware of the ONU is normal.

Step 4 The ONU on which the fault occurs is located in a remote mountain area. Therefore, it is suspected that the fault is caused by the surroundings. Log in to the ONU in the telnet mode, and then run the display alarm list all command to carefully view the alarms. It is found that the ONU resets in peak hours from 7:00 a.m. to 8:00 p.m. in four consecutive days. Therefore, it can be preliminarily determined that the fault is caused by the voltage.

Step 5 Use a multimeter to test the voltage on site. It is found that the ONU resets repeatedly due to unstable voltage. Replace the ONU with another ONU with the DC module. As a result, the fault is rectified.

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Suggestion and Conclusion

The ONUs of Huawei support AC power supply and DC power supply. If an ONU uses the AC power supply, the ONU resets repeatedly when the voltage is unstable. If the voltage is abnormal and the normal voltage cannot be guaranteed, it is recommended that you use an ONU with the DC module.

More topic for MA5600 series:

MA5683T VS MA5603
The basic configuration of OLT
How to configure DHCP on Huawei MA5680T
The command debugging dns of Huawei MA5631
MA5600/MA5603: CONFIGURING THE LICENSE FUNCTION

MA5616 VS MA5612

What’s the difference between the MA5616 and MA 5612?

MA5616, can be used to MDU/DSLAM

MA5616 provides ADSL2+, VDSL2, SHDSL, POTS, ISDN, FE, GE and other user interface ports.

MA5616 needs its own configuration, (the generally is: the machine frame + control board + business board + power plate + user line), our classic configuration for the MA5616 with CCUB Main Control Board, 4 Units ADLE 32 Ports ADSL2+ Board, AC Power (or DC Power) +4 Units ADLE User Cable, 3Meter.

The GPON board The user board includes two models: 32 ADSL2+ board and 64 ADSL2+ board.

MA5612 can be used to MDU

MA5612 can support voice, data (FE, GE), and there are 2 slots, can be added single board, there are several models of MA5612:

MA5612: 2GE+6FE+16POTS

MA5612: 2GE+6FE