Single Mode Fibre Link

Hi
Not sure if anyone can help but… I have a link across a school playing field of single mode fibre (don't ask me why its single mode, I wasn't involved in the installation!!). It has 4 cores 2 of which are connected quite happily into SFP’s and working. I am trying to connect up the other 2 cores using single mode 100mbps media converters and I just can’t get a signal. I have tested the cable itself and its fine. I have purchased brand new media converters and patch leads and it just won’t work.

Any ideas? I am getting to the point where we may have to run a new fibre (Multimode!!) as this has got to be working by 15th September!!

Thanks!

I'm guessing that if it's a long enough run that's why they installed singlemode fibre?

Do your patch leads match the type of cable installed?

Ben

What did you use to test the cable itself, can you try switching the existing modules over to the other pair to make see if that works over the link. Have you considered upgrading the existing link to 1gb which would solve bandwidth issues.

Yeah, I am using the correct single mode patch leads at both ends. The distance isn't outside the range of multimode fibre by a long shot so I have no idea why they used single mode. I tested the cable by doing exactly that - switching the existing connection over to the other pair and it worked fine!

I am at a complete loss!

There must be a mismatch somewhere in the new stuff you've bought then.

Ben

I'm just having a single-mode link installed to our additional campus for use from next year, we went for single model over the others as the distance was getting to the limits for 10GBe over OM3, thus we felt as its a one-off install this and needs to last and be as future-proof as we can we should go for the best we can do and this will happily support 10GBe over much longer distances so when we get 100GBe and the rest then we hope that we will be covered by just new converters!

Like Plexer says you must have a mis-match in your equipment.

Post details of the kit you are connecting to your SM Fiber and we wil see where your going wrong...

You confirmed yourself that the fiber is good!

Unless your Media Converters say they are Single Mode do not assume they are!

If you have to use media converters you should have ones that switch 10/100/1000 Copper and take SFP Modules as its a lot easier to make all of the different media talk to each other... look at the Level One GVT-4000's we use them all the time.

I am using Planet FT-802S15 media converters and LC-SC single mode patch leads.

Any clues?

Have you crossed one side over when connecting the patch leads or do they do it automatically for you?

Ben

I would have assumed that the patch leads would do it for me however, I'm going to have a go. I can't think of anything else that would work!

I'll let you know!

**!!UPDATE!!**

Sorted it!! The stupid patch leads just needed crossing over!!

Cheers everyone!