In general, the luminous power of the optical fiber transceiver or optical module is as follows: multimode is between 10db and -18db; single mode is 20km between -8db and -15db; and single mode is 60km is between -5db and -12db between. But if the luminous power of the fiber optic transceiver appears between -30db and -45db, then it is very likely that this fiber optic transceiver has a problem.
How to judge whether there is a problem with the fiber optic transceiver?
(1) First, see if the indicator light of the optical fiber transceiver or optical module and the indicator light of the twisted pair port are on
a. If the FX indicator of the transceiver is off, please confirm 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.
b. 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 on the A transceiver side: one possibility is: A transceiver (TX) optical transmission The port is bad because the optical port (RX) of the B transceiver does not receive the optical signal; another possibility is: there is a problem with this fiber link of the optical transmission port of the A transceiver (TX) (the optical cable or the optical jumper may be broken).
c. The twisted pair (TP) indicator is off. Please make sure that the twisted pair connection is wrong or the connection is wrong? Please use a continuity tester to test (however, the twisted pair indicator lights of some transceivers must wait until the fiber link is connected).
d. Some transceivers have two RJ45 ports: (ToHUB) indicates that the connecting line to the switch is a straight-through line; (ToNode) indicates that the connecting line to the switch is a crossover line.
e. Some hair extensions have 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 to the switch is a cross-over mode.
(2) Whether the optical cable and optical fiber jumper have been broken
a. Optical cable connection and disconnection detection: use laser flashlight, sunlight, luminous body to illuminate one end of the optical cable connector or coupling; 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 laser flashlight, sunlight, etc. to illuminate one end of the fiber jumper; see if there is visible light on the other end? If there is visible light, the fiber jumper is not broken.
(3) Whether the half/full duplex mode is wrong
Some transceivers have FDX switches on the side: full duplex; HDX switches: half duplex.
(4) Test with optical power meter
The luminous power of the optical fiber transceiver or optical module under normal conditions: multi-mode: between -10db and -18db; single-mode 20 kilometers: between -8db and -15db; single-mode 60 kilometers: between -5db and -12db ; If the luminous power of the fiber optic transceiver is between -30db-45db, then it can be judged that there is a problem with this fiber optic transceiver.