1. The Power light not on

The power failure

2. There will be one of the following problems when the LOS light does not work:

(a) The cable from the machine room to the client has been broken.

(b) The slots for the SC tail and fiber transceiver are not properly inserted or disconnected.

3. Link light is not on; there may be the following situations:

(a) Check whether the optical fiber line is broken

(b) Check whether the loss of optical fiber line is too large and exceeds the receiving range of the equipment.

(c) Check whether the optical fiber interface is properly connected, the local TX is connected to the distant RX, and the distant TX is connected to the local RX.

(d) Check whether the optical fiber connector is properly inserted into the device interface, whether the jumper type matches the device interface, whether the device type matches the optical fiber, and whether the transmission length of the device matches the distance.

4. The circuit LINK light is not on, and the fault may be as follows:

(a) Check whether the network cable is broken.

(b) Check whether connection types match: network cards and routers and other devices use crossover lines, while switches and hubs and other devices use straight-through lines.

(c) Check whether the transmission rate of the device matches.

5. Serious possible failures of network packet loss are as follows:

(a) The electrical port of the transceiver does not match the network device interface, or the duplex mode of the device interface at both ends.

(b) There is a problem with the twisted pair and RJ-45. Test it.

(c) The problem of optical fiber connection, whether the jumper is aligned with the device interface, whether the tail fiber matches the type of jumper and coupler, etc.

6. The two ends of the optical fiber transceiver cannot communicate after connection

(a) The optical fiber is connected in reverse, and the optical fiber connected by TX and RX is switched.

(b) The RJ45 interface is not connected correctly with the external equipment (pay attention to the straight connection and splice connection).

The optical fiber interface (ceramic core) does not match. This fault is mainly reflected in the 100M transceiver with photoelectric mutual control function. For example, the tail fiber of the APC core cannot communicate normally with the transceiver of the PC core, but it does not affect the connection with the non-photoelectric mutual control transceiver.

7. Time on time off phenomenon

(a) It may be that the optical path attenuation is too large. In this case, optical power meter can be used to measure the optical power of the receiving end. If it is near the receiving sensitivity range, the optical path fault can be basically judged within the range of 1-2dB

(b) It may be that the switch connected to the transceiver is faulty. At this time, replace the switch with a PC, that is, the two transceivers are directly connected to the PC, and both ends are PING. If it does not appear, it can be basically judged as a switch failure.

(c) may be transceiver failure, can take on both ends of the transceiver PC (not through the switch), both ends of the PING no problem after transmitted from one end to the other end a large file (100 m) above, to observe its speed, such as slow (200 m below the file transfer more than 15 minutes), but the basic judgment for the transceiver.

8. Communication crashes after a period of time, that is, communication cannot be resumed after reboot

This phenomenon is generally caused by the switch, the switch will carry out CRC error detection and length check on all the received data, the packet detected with error will be discarded, the correct packet will be forwarded. But there is an error in the process, some bags in the length of the CRC error detection and validation test not to come out, this bag in the forwarding process will not be sent out, it wouldn‘t be discarded, they will accumulate in the dynamic cache (buffer), will never be able to send out, until the accumulated in the buffer is full, can cause the switch crash phenomenon. Because either restarting the transceiver or the switch can restore communication, the user often assumes that the transceiver is at fault.

9. Transceiver Test Method If there is a problem with the transceiver connection, test as follows to find out the cause of the fault

(a) Proximal testing:

The computers at both ends are pinging, if it can ping, it proves that there is no problem with the fiber optic transceiver. If the near-end test fails to communicate, it can be judged that the fiber optic transceiver is faulty.

(b) Remote testing:

If the PING is not normal, the computer at both ends must check whether the optical connection is normal and whether the transmitting and receiving power of the optical fiber transceiver is within the permitted range. If you can PING the general rule to prove that the light connection is normal. The fault can be judged on the switch.

(c) Distant test to determine fault points:

Connect one end to the switch first, and the two ends are PING. If there is no fault, it can be judged as the fault of the other switch.