Optical signal transmission

[LongNg]

Hi everyone
I’m facing a strange issue and would like to ask for your advice. When I plug the SFP (fiber) module into the switch, all cameras and NVRs lose connection and there’s no signal at all. However, when I completely remove the SFP module from the fiber port, all cameras and NVRs immediately come back online.
Has anyone ever encountered this situation before? What could be the cause, and how can it be fixed? I’d really appreciate any suggestions or insights. Thanks

 

[Underhill]

I’d have to wonder what’s on both ends? Do you have 2 devices both trying to issue addresses? Other thing might check; are both fiber and sfp’s matched (both multi or single mode)?

 

[Holbs]

1.) if both are managed switches, ensure not using same IP
2.) swap SFP modules from top to bottom and vice versa. See if problem follows.
3.) swap LC connector ends from left to right, and vice versa. See if problem follows.
4.) ensure you did not create a loop. Positive you do not have copper connecting between the switches?
5.) test the fiber patch cords / fiber cable. don't look into the laser. hold LC ends and point to piece of paper or your hand for troubleshooting to ensure laser is coming out of the correct LC connector and not out of the other one.
6.) test with another fiber capable switch.

 

[kd5mdk]

I would say the likelihood is 95% there is another connection between those two endpoints and you are causing a loop. (Or the fiber is making a U turn and you’re connecting both ends of it to the same switch. I’ve done that with copper going through a wall.) Especially because you said that the devices are online before and after the disconnection.

Also knowing what devices are on each end of the fiber will help a lot.