The Catalyst 2900 series XL modules can add port density and fiber-optic connectivity to a Catalyst 2900 series XL network. When installed in a Catalyst 2912MF, 2916M or 2924M (Requires software version 11.2(8)SA4. If they don't have that version, they need to get a smartnet to upgrade. If they have a 2916M-XL or 2924M-XL-A, they can buy the Enterprise software upgrade.) switch, these modules support switched 10BaseT, 100BaseTX, 100BaseFX, 1000BSX, or 1000BLX connections. The 10BaseT/100BaseTX module autonegotiates the duplex and speed settings of each port to match that of the attached device.