The Catalyst 2960CPD-8TT-L, 2960CPD-8PT-L, and 3560CPD-8PT-S switches do not have a internal power supply. You can power the switch through either the 10/100/1000 uplink ports or through an auxiliary power adapter. You can order the auxiliary power adapter (PWR-ADPT) with the switch, or you can order it (PWR-ADPT=) later from your Cisco representative.