Common Fault Judgment Method of Optical Fiber Transceiver

- Sep 18, 2019-

There are many kinds of optical transceivers, but the fault diagnosis methods are basically the same. In summary, the faults of optical transceivers are as follows:

1. Power lamp power failure

2. Link lamp failure may be as follows:

A. Check whether the optical fiber line is broken.

B. Check whether the loss of the optical fiber line is too large to exceed the receiving range of the equipment.


C. Check whether the optical fiber interface is connected accurately, the local TX is connected to the remote RX, and the remote TX is connected to the local RX.

D. Check whether the optical fiber connector is well inserted into the device interface, whether the jumper type matches the device interface, whether the device type matches the optical fiber, and whether the device transmission length matches the distance.

3. Circuit Link lamp failure may be as follows:

A. Check whether the network is disconnected

B. Check whether the connection type matches: the network card and router use crossing lines, switches, hubs and other equipment use through lines.

C. Check whether the transmission rate of the device matches.

4. Severe possible failures of network packet loss are as follows:

A. The electrical port of the transceiver does not match the duplex mode of the network device interface or the device interface at both ends.

B. The twisted pair and RJ-45 head have problems and are tested.

C. Optical fiber connection problems, whether jumpers are aligned with equipment interfaces, whether tail fibers and jumpers and coupler types are zoned, etc.

5. The two ends of the optical transceiver can not communicate after connection.

A. Fiber optic inversion, TX and TR fiber alignment

Incorrect connection between interface B and RJ45 and peripheral equipment (emphasis on direct connection and stranding)

Fiber optic interface (ceramic socket) does not match. This fault is mainly reflected in the 100M transceiver with photoelectric mutual control function. For example, the tail fiber of APC socket can not communicate normally when it connects to the transceiver with PC socket, but the connection of non-photoelectric mutual control transceiver has no effect.

6. Time Interruption Phenomenon

A. It may be that the attenuation of the optical path is too large. At this time, the optical power of the receiving end can be measured by an optical power meter. If the receiving agility range is around, the optical path fault can be basically judged in the range of 1-2dB.

B. It may be a switch fault connected with the transceiver. At this time, the switch is replaced by a PC, that is, two transceivers are connected directly with the PC, and the PING at both ends can be basically judged as a switch fault if there is no time-interrupt phenomenon.

C. It may be the fault of transceiver. At this time, the transceiver can be connected to the PC (not through the switch). After the two ends have no problem with PING, a large file (100M) can be transmitted from one end to the other end. The speed of the file (100M) can be basically judged as the transceiver if the speed is very slow (more than 15 minutes of file transmission below 200M). Malfunction.

7. Communication crashes after a period of time, that is, it cannot communicate, and returns to normal after restart.

This phenomenon is generally caused by switches. The exchange opportunity detects CRC errors and checks the length of all received data, checks that the wrong packets will be discarded, and the correct packets will be forwarded. But in this process, some wrongful packages can not be detected in CRC error detection and length checking. Such packages will not be sent out or discarded during forwarding. They will accumulate in dynamic buffer and never be sent out. When the buffer is full, they will result in handover. The phenomenon of machine change and crash. Since restarting the transceiver or the switch can restore the communication to normal, users usually think that the transceiver is a problem.

8. Transceiver Test Method

If you find that there is a problem with the transceiver connection, please test it according to the following methods in order to find out the cause of the failure.

A. Near-end testing

If the PING communication between the two computers proves that there is no problem with the optical transceiver, and if the proximity test is not reliable, the fault of the optical transceiver can be judged.

B. Remote Testing

If PING is not connected to both computers, it is necessary to check whether the optical connection is normal and whether the transmitting and receiving power of the optical transceiver is within the allowable range. If PING general proves that the optical path connection is normal. The fault can be judged on the switch.

C. Distance Testing to Judge Fault Points

First, one end is connected to the switch, and the other end is PING. If there is no end barrier, it can be judged as the fault of another switch.

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