Description of the problem

A power customer uses a friendly transmission device for point-to-point communication between RTU devices at sites A and B as shown below:

Now the customer uses Huawei OSN3500 equipment to replace the friendly transmission equipment, and after all the services from RTN-1 to RTN-9 are cut to Huawei OSN3500 equipment, it is found that RTN1-8 services are normal, RTN-9 services are abnormal, and the RTN-9 equipment system is unable to communicate normally. The following figure is shown:

Alarm message

Customer feedback, RTN9 device is not working properly

Processing

1. Check the OSN3500 device Port9 port attribute settings, and the channel configuration that carries Port9 port services, and there is no difference with Port1-8;

2. Connect RTU-1 to Port9 and RTN-9 to Port1, and find that RTN-1 device works normally and RTN-9 device still cannot communicate normally, as shown below. It indicates that the service configuration of OSN3500 devices from Port1 to Port9 port are normal.

3. Check the rate, step size, same-asynchronous and other parameters of the RTN-9 device, and find that the configurations of RTN-9 and RTN-1 to RTN-8 are also exactly the same. Rule out customer device configuration problems.

4. Sort out the connection relationship between RTN devices and OSN3500 devices as follows:

When positioning in step 2, RTU-1 and RTU-9 channels are switched, it is swapping the RJ45 connection on the adapter, and RTU-1 is still normal and RTU-9 is abnormal after switching.

Therefore, it can be concluded that: ① the new cable (green), the line sequence is normal; ② it is likely that the "adapter" problem.

The picture of the adapter is as follows:

5. Let the customer troubleshoot the adapter, the customer disassembled it and found that the wire sequence of the adapter is different from other adapters.

6. After replacing the adapter with a normal wire sequence, the RTU-9 device works normally.

Root cause

Customer DB9 to RJ45 adapter wiring sequence abnormality, resulting in service failure.

The RTU-9 is working fine because the wiring sequence of the ports of the friend's device has been changed along with the adapter.

Solution

Replace the adapter with the abnormal wiring sequence.

Recommendations and Summary

None

This chapter related technical information and SDH equipment troubleshooting process by Shenzhen Optical Transmission Network Technology Co., Ltd ( www.opticaltrans.com), reproduced please retain! Huawei SDH Optical Transmission Equipment,SDH Transmission Equipment Sales