I have a WS-C2960CX-8PC-L switch and a DWDM-SFP-4056 GBIC. If I'm reading http://www.cisco.com/c/en/us/td/docs/interfaces_modules/transceiver_modules/compatibility/matrix/GE_Tx_Matrix.html#_Toc476298501 right then they should be compatible. However, ...