I have a situation where a campus has about 15 buildings that are all connected by fiber to 2924M-XL switches (100Mb fiber ports). We are trying to up grade the backbone building by building. We have 3560 and 3750 switches with GLC-SX-MM modules, we have tried everything we can think of but the 2924 switches do not see the 3560 or 3750 models.

Is this possible? I would have thought the 1000 MB module was backwards compatable. HELP!

Thank You