Dodgy fibre optic media converters?

[Ravening_Wolf]

I have had a problem today whereby one of our "satellite" cabinets (and therefore attached devices) have dropped off the network. A quick check of the fibre optic media converters has shown that the fibre is not "communicating".

I have checked both ends of the optic cable and both are showing lasers indicating that the cable is not damaged. I have rebooted media converters and also tried different media converters on both ends. The cable itself has two pairs of fibre and I have tested both without success.

Fibre optics are not my strong point (i.e. I have no idea), but the fact that a visual test indicates that the cable is undamaged, I am suspecting faulty media converters.

Could anyone advise what to do next? I'd be happy to leave it until next week but my office runs off the affected cabinet!

[Ric_]

Try different media converters?

[Ravening_Wolf]

Different make/model?

[Ric_]

I would have said that just changing them for a known working one would help narrow things down.

[maniac]

I've had loads of media converters fail on me in the past. Make sure the one you're substituting it for is known to be working.

Common problem with fibre is getting the TX and RX the wrong way round (particulalry on ST connectors) The fibre converter should show when it's sucessfully established a connection, if it doesn't try changing them round.

Also to double check the fibre in your building, get a small torch (mini maglights work well) and have someone shine it down one end of the cable while you look at the other. You should get a strong beam of light down each fibre.

Mike.

[Tom_ONI]

Fibre converters are the devil. Not very scientific but true.

As suggested above trying with converts you know are working is the first step, I have seen dodgy converts a few times and it is very rarely a fibre issue.

Tom

[john]

Make a loopback on the media converter on the fibre side. Remove the copper side and loop 1 cable from TX to RX on the Fibre side and see if it then shows a link fine, if not dodgy converter.