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Help with fiber connect between switches

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Kevin D. Sowder
Occasional Visitor

Help with fiber connect between switches

Just purchased the following:
1-2848 switch
1-2824 switch
2-SX LC GBICs
1-50m length of fiber with LC connectors
Can't get a connection between switches. See the light in the cables and in the GBICs. The ports won't come up. The switches have simply been given an IP to telnet to them. Can someone help?
Thanks in advance!
5 REPLIES
Les Ligetfalvy
Esteemed Contributor
Solution

Re: Help with fiber connect between switches

On the mini-GBICs you should see two little triangles that show what direction the light should travel. I suspect that your LC - LC jumper has the wrong polarity and the TX is going to TX and RX to RX.
Kevin D. Sowder
Occasional Visitor

Re: Help with fiber connect between switches

Thanks, Les. I'll take a look tomorrow. I know this is probably old hat to you, but to me, it's kinda new stuff. Never had GBICs before.
Thanks again for your help!
Kevin
Kevin D. Sowder
Occasional Visitor

Re: Help with fiber connect between switches

Les, Thanks for your answer. I checked my GBIC and they don't have jumpers. My LC-LC cable doesn't have jumpers anywhere. How do I change polarity on this config? Is this something I can do on the port? I don't understand your use of jumper. Sorry.
Thanks again
Les Ligetfalvy
Esteemed Contributor

Re: Help with fiber connect between switches

Did you follow the fibre light trail and confirm it is in fact a polarity thing? The GBICs cannot change the polarity. That is done with the fibre jumper.

Looking into the end of the GBIC, The TX would be on the left and the RX on the right. On the fibre zip cord, one side should have printing on it. Look for the same printing on the other end to see that it crosses over to the other side of the GBIC. I just looked at one of my LC/LC jumpers and it does. If your jumper does not cross over, you are SOL unless you want to try to pull the bridge apart and reverse it. If you break the bridge, you can still use the jumper. My mode conditioning jumpers are not bridged together.

Most of my fibre jumpers go through building fibre that terminate with ST so with those, it is a simple matter of reversing the connectors on the ST side.
Kevin D. Sowder
Occasional Visitor

Re: Help with fiber connect between switches

Thanks again, Les. I am SOL on this one. I don't know if there is such a thing as a polarity changing cable, but I'm going to look around. I suppose I could break the end in half... why not?
Thanks again,
Kevin