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3Com switches and 1000Base SX problem

I have a strange problem. Our customer has multimode fiber installed between wiring closets. They have 3Com 3300 series switches and 4007 switches both with 1000BaseSX ports. 3300s can connect to 3300 from closet to closet, 4007 can connect to 4007 from closet to closet, but if you take the same fiber and plug in 3300 to 4007, it won't even get link. If you plug in a 3300 to a 4007 just with a 6' patch fiber, it will work. The fiber between the closets are not very long at all. It's probably less than 100'.

Anyone have any ideas on what to look for?

TIA,

Jay

Reply to
flamingjay
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Yeah, that's the first thing I tried. I have also tried disabling auto-negotiation, etc.

Reply to
flamingjay

In article , wrote: :I have a strange problem. Our customer has multimode fiber installed :between wiring closets. They have 3Com 3300 series switches and 4007 :switches both with 1000BaseSX ports. 3300s can connect to 3300 from :closet to closet, 4007 can connect to 4007 from closet to closet, but :if you take the same fiber and plug in 3300 to 4007, it won't even get :link. If you plug in a 3300 to a 4007 just with a 6' patch fiber, it :will work.

You might have explored this already...

but that sounds like it might be a difference between the transmit and receive pairing. Did you try exchanging the pair members in one place?

Reply to
Walter Roberson

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