I am "attemtping" to connect a 2960-48TC-L to a 2960S-24PS-L using SMF modules. I have tried both, the GLC-FE-100FX and GLC-GE-100FX modules and each time, the 2960-48TC drops connectivity via the SMF port. I have had to connect via copper. The only thing I can see happening on either switch is that the 2960S encounters "Stack Packet Errors". Any idea of why this is happening? I have tried all the various combinations of modules FE to FE, GE to FE, GE to GE and all produce the same result.
I saw something "2960 Data Sheet" in "Table 6" that the "*The Cisco Catalyst 2960-S with SFP+ does not support the GLC-FE-100BX, GLC-FE-100FX, or GLC-FE-100LX." - further in the document - Table 15 - it shows these compatible as well as in the "Module Compatibility Matirx".
What does the "SMF+" mean?
Have a look here:
Some 2960S Switches have SFP+ slots - 10GB SFP+ mobules can be used with these switches
The models you listed only have SFP slots so the passage you quoted would suggest your modules would work. What GE module have you tested with?
The distance is only 1 ft as they are in the same cabinet and I have tried using the GLC-FE-100FX on both ends as well as the GLE-GE-100FX on both ends. I have even swapped the A&B in the LC cable and no help.
1 feet away? Then GLC-FE-100FX should be used. Now both the 2960 and 2960S support this module. But are you sure your patch cable is a multi-mode cable? Is your cable faulty?