Description of the problem

An electric power customer's RTU equipment uses RS232 low-speed service for communication, and the middle is carried by transmission equipment. In the following figure, for example, there are two groups of ARTU-1 and RTU-2 devices at sites A and B, and their service signals are transmitted through the Z-vendor's transmission equipment.

After two new Huawei OSN3500 units were built, the service was cut from vendor Z to OSN3500 equipment. In the cutover, RTU-1 was found to be normal, but RTU-2 was abnormal (customer feedback that the terminal RTU equipment could not work normally), as shown below

Alarm information

There is no alarm on OSN3500 transmission, and the port of RTU-2 of the customer cannot be UP.

Processing

1. Check the service configuration of transmission OSN3500: through comparison, OSN3500 device carries RTU-1 and RTU-2 signals with the same service configuration and port attributes, which excludes MSTP configuration problems.

2. In site A, the OSN3500 Port2 port hardware loopback, in site B, hang the meter test, the test is normal, to rule out MSTP channel problems.

3. Reverse the RTU-2 service back to "Z vendor transmission equipment", found that the service is normal, to rule out customer RTU system problems.

4. Switch the two channels of OSN3500: Port1 channel carries RTU-2 service, and Port2 channel carries RTU-1 service, and found that RTU-1 service is still normal, and RTU-2 service is abnormal (as shown below), basically ruling out Huawei's equipment problems, and suspecting that the customer's RTU-2 service is still normal.

1, RTU-2 equipment business configuration has differences.

5. Communicate with the customer about the differences between RTU-1 and RTU-2 devices, and compare the port attributes of Huawei OSN3500 Port2 with the service configuration parameters of the customer's RTU-2 device one by one, and check the configuration differences between RTU-1 and RTU-2.

6. Finally, the port rate of the customer RTU-2 device is found to be different from that of the RTU-1 device:.

1 RTU-1 is 9600k (see the following figure)

2RTU-2 is 4800k (see below).

7. Change the port attribute of OSN3500 port2 to 4800k.

8.Re-connect the RTU-2 to the port2 port, and find that the RTU-2 works normally, the problem is solved.

Root cause

The service rate of customer RTU-2 does not match the rate of OSN3500 device.

Solution

Modify the port rate of OSN3500 device to match with the rate of customer terminal equipment.

Suggestion and Summary

OSN3500 PCM features support RS232 low-speed service, the service has rate, byte length, the same asynchronous and other attributes, docking scenarios need to pay attention to.

This chapter of related technical information and SDH equipment troubleshooting process by Shenzhen Optical Transmission Network Technology Co. Huawei SDH optical transmission equipment, SDH transmission equipment sales