Currently we have a 3930 connected to an Ubiquiti switch just fine. We are moving to a 3750 for the advanced routing features, but the fiber link will not come up. Anyone have any thoughts? We have tried a multitude of SFPs and cables, but no go. I understand that the 3930 can negotiate between 100/1000Mbps. Cisco only does 1000Mbps (no negotiation). Could this be the issue?