WS-C3750G-24WS not recognizing GLC-SX-MMs

[Ken Wold]

I am trying to create a trunk between a WS-C3750G-24WS and a WS-C3750G-48PS both running 12.2(55) using MM fiber and Cisco GLC-SX-MMs. The strange thing is when I insert the GLC-SX-MMs into the SFP ports and do show int transceivers, I get no output.

When I try and connect the fiber patch between the two switches, I don't get a link up. If I remove the GLC-SX-MM from the WS-C3750-24WS and place it into the WS-C3750G-48PS (meaning the WS-C3750G-48PS has two GLC-SX-MMs) I can use a patch and I get a link with no problem.

I am kinda scratching my head as to why the WS-C3750-24WS is not working with my Cisco GLC-SX-MMs.

[Reza Sharifi]

Do you have an extra available port on WS-C3750-24WS to connect to determine if the port is bad?

It could also be an IOS issue. Try downgrading or upgrading the IOS on it and see if the problem goes away

[sajid_m123]

Aftere you insert transceiver into the swtich then do "sh idprom interface gigabitEthernet#" and check if you get SFP info.

Moreover, if you make a loop throug a fiber i.e insert one end of a fiber in one port and other end of the same fiber to the other port, do you see link coming up?