Common fiber failures and their solutions

The thin optical fiber is encapsulated in a plastic sheath so that it can be bent without breaking. Generally, the transmitting device at one end of the optical fiber uses a light-emitting diode or a laser beam to transmit light pulses to the optical fiber, and the receiving device at the other end of the optical fiber uses a photosensitive element to detect the pulses.

First, whether the indicator light of the optical fiber transceiver or optical fiber module and the indicator light of the twisted pair port are on

If the FX indicator of the transceiver is off, please make sure whether the fiber link is cross-linked; one end of the fiber jumper is connected in parallel; the other end is connected in cross mode. If the optical port (FX) indicator of the A transceiver is on and the optical port (FX) indicator of the B transceiver is off, the fault is at the A transceiver: one possibility is: the A transceiver (TX) optical transmission port has been Bad, because the optical port (RX) of the B transceiver cannot receive the optical signal; another possibility is: the optical fiber link of the optical transmitting port of the A transceiver (TX) has a problem (the optical cable or optical fiber jumper may be broken ).

Twisted pair (TP) indicator is off, please make sure whether the twisted pair connection is wrong or the connection is wrong. Please use a continuity tester to test; some transceivers have two RJ45 ports: (To HUB) indicates that the cable connecting the switch is a straight-through line; (To Node) indicates that the cable connecting the switch is a crossover cable; some transmitters There is an MPR switch on the side: it means that the connection line to the switch is a straight-through line; DTE switch: the connection line that is connected to the switch is a crossover line.

Second, use an optical power meter to detect

The luminous power of the fiber optic transceiver or optical module under normal conditions: multimode: between -10db and 18db; single mode 20 km: between -8db and 15db; single mode 60 km: between -5db and 12db ; If the luminous power of the optical fiber transceiver is between -30db--45db, then it can be judged that there is a problem with the transceiver.

Third, is there any error in the half/full duplex mode

There is an FDX switch on the side of some transceivers: it means full-duplex; HDX switch: it means half-duplex.

Fourth, whether the fiber optic cables and fiber jumpers have been broken

a. Optical cable on-off detection: use a laser flashlight, sunlight, or illuminator to illuminate one end of the optical cable connector or coupler; see if there is visible light at the other end? If there is visible light, it indicates that the optical cable is not broken.

b. On-off detection of optical fiber connection: use a laser flashlight, sunlight, etc. to illuminate one end of the optical fiber jumper; see if there is visible light at the other end? If there is visible light, it indicates that the fiber jumper is not broken.