1. 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 means that the optical cable is not broken;

2. On-off detection of optical fiber connection: use 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 means that the fiber jumper is not broken.

3. Whether the half/full duplex mode is correct.

Some transceivers have FDX switches on the side: full duplex; HDX switches: half duplex.

Fourth, use the optical power meter to detect.

The luminous power of the optical fiber transceiver or optical module under normal conditions: multi-mode: between -10db--18db; single-mode 20km: between -8db--15db; single-mode 60km: between -5db--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.