Fault handling during daily use of optical transceiver

1 The input signal of a branch of the optical transceiver disappears

Fault phenomenon: Datun-Xuzhuang branch office has a poor phone call, and there is a phenomenon that the trunk circuit is busy.

Analysis of the fault range: Daxun-Xuzhuang has three 2Mb/s ports relay circuits (90 voice channels). According to the fault phenomenon, the circuit is not fully blocked, indicating that it is not an optical path or a group path fault. Whether it is a large amount of traffic, the capacity of the relay circuit is small, the possibility is small, because the traffic volume analysis last month is 0.2 erl / line, and the failure is not the peak traffic. There is only one possibility: one of the 2Mb/s branches is faulty.

Fault location processing:

(1) Observing the alarm information of the large-scale optical transceiver, it is found that the 2/8 multiplex board to the Xuzhuang direction has a red light, and at the same time, the monitoring alarm board I1 is lit, indicating that the 2M1 branch of the board is faulty.

(2) Judging whether the optical transceiver unit is faulty or the input interface of the programmable computer room to the optical transceiver is faulty, there are two methods to determine: the first type, the branch input port is self-loop, and if the fault does not disappear, the branch unit is Fault; if the fault disappears, it is the fault of the programmable machine room side. Secondly, the input port of the branch is monitored online by the transmission performance analyzer. If the code is normal, the optical unit branch unit is faulty; if the code entry is interrupted, it is the program-controlled equipment room side. I used the first method to judge the fault of the program-controlled machine room side.

(3) Further test online at the point B of the digital distribution frame with a transmission analyzer as "code-in interrupt", indicating that the fault is between the switch unit and the digital distribution frame input port.

(4) Immediately notify the personnel of the program control room to observe the status of the switch. It is found that the relay board of the white circuit has an alarm light, and the board is changed immediately, the alarm disappears, and the circuit is unblocked.

This fault is caused by the switch-related digital relay unit signaling no output. This type of failure also occurs frequently on the connector of the cable between the switch and the optical transceiver. Immediately use the spare line to grab the circuit.

2 group road failure

Fault phenomenon: Datong to Shuangquan phone is not available, the circuit is fully blocked.

Analysis of the fault range: This is an optical transceiver group fault. Because Shuangquan is in the position of the relay station, at this time, the two adjacent branches of the two Yi and Xuzhuang telephones are normal, indicating that the Shuangquan-Dayu cable and the optical path are normal. The reason may be a double-spring or large-scale high-order group multiplex tapping failure.

Fault location 1 processing:

(1) Observe the alarm status of both optical transceivers and corresponding switches.

a. The yellow light of the 2/8 multiplex board of the large optical transceiver is on, and the alarm lights of the monitoring alarm disk I7 and I8 are on. They indicate that the group road receives the report and the AIS signal; the big switch is a red light relay alarm.

b. Shuangquan optical transceiver has no alarm information; Shuangquan switch has yellow light to report information.

c. At the 2Mb/s branch of Shuangquan Optical Transmitter, the Shuangquan Optical Transmitter does not alarm. The Daxie uses the BER tester to open the test at 2Mb/s port. The 4 2Mb/s ports are frame out of step. At the same time, I received AIS. From the above phenomenon, it can be judged that the fault is between Shuangquan and Daxin.

(2) Replace the Shuangquan and Daxie multiplex boards with the replacement method, and the alarms did not disappear.

(3) Measure the voltage of both power supply boards, both are normal.

(4) Turn off the power supply of the Shuangquan rack, restart, the alarm does not disappear; turn off the power of the large rack, restart, and the alarm disappears.

This fault is caused by the data of an integrated block of the optical transceiver, and needs to be powered off and restarted. Similar faults have appeared on the optical transceivers in the direction of Welin.

3 light receiving failure

Trouble phenomenon: The user complained that there is noise in the call of the lower village, and it is good when the time is off.

Analysis: The Xiazhai branch office is located at the relay station of the optical transmission system. Through the trial of the neighboring station Bai Bai and Zhang Jia, the white and Zhang family also have similar phenomena, indicating that the fault is a light transmission group fault, and between the white and the big.

Fault location, processing:

(1) Observe the optical information of both optical transceivers:

Observing the optical transceiver of the Daban Bureau, it was found that the red and yellow lights of the light board were alternately flashing, and the lights were off when the lights were on; the monitoring alarm disks I7 and I8 were on. These messages indicate that Daxie received 10-3 and 10-6 code information; observed the white light relay machine without any alarm information. These indicate that this is a single-direction optical path failure.

(2) It is judged whether the optical board is faulty or the optical cable is faulty. There are three methods: a. Replace the two optical boards with the standby board and the faults have not disappeared, indicating that the fault is a cable fault, otherwise, it is a device fault. b. Using the optical power meter to separately measure the light emission and light receiving power, it can also determine whether the light board or the optical cable is faulty. c. Using the pigtail + light attenuator to send and receive the ring from the optical board can also determine whether the optical board or the optical cable is faulty. I used the first method to judge the cable failure.

(3) If the optical cable has a spare core, it can be exchanged; if there is no spare core, it is necessary to carefully judge whether it is a pigtail or an outdoor cable. Because the single-core cable is not good, and it is not broken, the outdoor cable is broken. The possibility is small, it is better to check the pigtail first.

I replaced the existing pigtails between the light distribution frame and the light board with the spare pigtails at the big end, and the fault disappeared. If the fault does not disappear, further judge the other pigtail and outdoor cable.

From the above example analysis, the basic methods for troubleshooting optical fiber digital transmission systems can be summarized as follows:

(1) Defining the nature and scope of the fault

In general, the transmission room is equipped with optical transceivers in several directions. Through the fault phenomenon, it is first necessary to determine which direction is the fault, whether it is an external fault or an internal fault, a group road fault or a branch fault, whether it is an optical transceiver fault or other base group such as a switch. The device is faulty. This requires maintenance personnel to fully understand the overall concept of optical fiber digital communication systems, and understand the relationship between transmission and switching, power systems. In this way, the fault can be judged as soon as possible to determine the nature and approximate range of the fault.

(2) Fault location of optical transceiver

By carefully observing the various alarm information of the equipment and the operation of the corresponding group equipment, combined with the meter test, comprehensive analysis will determine the fault section as soon as possible until it is compressed to the fault location.

This requires maintenance personnel to be familiar with the path organization and wiring system. Usually, it is necessary to have a mind, failure, and hold until it is eliminated. This gradually accumulates experience and can be flexible and maneuverable when dealing with faults.

(3) Optical fiber terminal fault handling method

The main means for equipment fault handling is to replace the circuit board, which must be equipped with a certain number and type of circuit boards; for the cable, the connector head is faulty, first replace it with a spare trunk line, and grab the circuit as soon as possible; be cautious for the faults belonging to the cable part When there is a spare core, it should be used first, and then contact the line maintenance personnel for processing.