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3750 and fiber Issue

I have a WS3750g-12s running IOS ver 12.5(25)SEB2. I have 9 ports configured as routed

ports, 8 of which goto seperate IDF's. The ninth port I want to use as an uplink to my

Firebox X2500. The problem is the 3750 has all fiber ports and the Firebox has all

RJ-45. I purchased a glc-fe-100fx tranciever and a CyberXLinkj CXL3M1-2 Media converter to connect the two. The twisted pair half of the media converter lights up fine however the FX side of the media converter is unlit. I tried turning off the auto negotiate property under the Cisco's port speed config but this made no difference. I than tried other media in the port. Plugging in a GLC-SX-MM into the same port and connecting the other end to one of my 3560-48's fiber port gives an almost immediate link light (portfast) on both devices. I then tried the glc-fe-100fx all by itself, and the when I plug it in I get the following error from the switch:

"gbic-invalid error detected on gb0/12, putting gb0/12 in err-disable state"

I get this error in any gbic on any of my Cisco's. Cisco documentation says that this error indicates a bad SFP, but this was bought new less than a month ago. Is there anything else I should check before assuming this is a bad SFP?




Re: 3750 and fiber Issue

The GIG-E Gbics will never talk to a Fast Ethernet fiber connection. There is no "AutoNegotiate" (for speed anyway) for fiber.

They use different frequencies and signaling (10 vs 100 vs Gig)

Good Luck


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