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New Member

Media Converter & Catalyst 3560 giving me headaches

Physical location 1  is connected to Physical location 2 with fiberoptic cable.

Location 1 fiber is terminated at Catalyst 3560.

Location 2 fiber is terminated at a media converter, so that the fiber link should be able to transparently be connected to a gigabit ethernet by rj45 cable.

The two fiber cables at each end is the same (62.5/125) - all is multimode fiber, and the gbic in the catalyst, and the media converter are both 850 nm.

On the Catalyst gbic where the fiber is, no link.

On the media converter there is link on the rj45, but no link on the fiber.

I cant seem to get what could be the problem.

The media converter is a tp-link mc200cm, which is gigabit, as well as the gbic module in the catalyst.

At first I bought the wrong tp-link (mc100cm - wavelength wrong) - however, on that, the fiber link lights (but very quick flashes only).

Any help, pointers oir the like would be greatlty appreciated!

New Member

Media Converter & Catalyst 3560 giving me headaches

Ok, now I double-checked everything.

It seems the gbit port in the catalyst is 1000base-sx, and the tp-link media converter expected a 1000base-fx.

Would that explain no link, and should buying a new media converter geared towards 1000base-sx rectify the situation?

Media Converter & Catalyst 3560 giving me headaches

It would seem the two devices should be compatible; both 850nm, short-reach interfaces and the instructions for the media converter shows a single-ended configuration. In the past, others have found that some media converters only operate in matched pairs; typically meaning they are not 802.3 compliant on their fiber links.   

Have you confirmed that the fiber connectors are clean and the fibers are routed to the correct ports (Tx to Rx, and Rx to Tx)?  Are the ports set on both devices for Auto speed and duplex setting?  Have you tested the fiber links to ensure they are good? If you loop the fiber cable on the 3560's GBIC from Tx to Rx, can you get link?  At the media convertor end, disconnect the fibers and connect the fibers together; does the 3560 show link? If you loop a fiber at the media converter's optical ports, does the media conv show link?

Let us know. Thx!