The Cisco eXpandable Power System (XPS) 2200 is a standalone power system that you can connect to Catalyst 3560-X and Catalyst 3750-X switches that are running Cisco IOS Release 12.2(55)SE1 and later. The XPS 2200 can provide backup power to connected devices that experience a power supply failure or, in a Catalyst 3750-X power stack, it can supply additional power to the power stack budget. The XPS 2200 power ports and internal power supplies can operate in redundant power supply (RPS) mode or stack power (SP) mode. When two power supplies are present, the system can operate in mixed mode, where one power supply operates in RPS mode and the other in SP mode. You can configure the ports and power supplies for the way that you plan to use the XPS 2200.