The server has a unit emergency power off (EPO) switch on the front of the first frame (A frame). When the switch is reset, the utility power is confined to the system power compartment, and all volatile data is lost.
Refer to the following figure, which shows a simplified unit EPO panel.
It is possible to attach the computer room emergency power off (EPO) system to the unit EPO. When this is done, resetting the computer room EPO disconnects all power from the power cords and the internal battery backup unit, if it is provided. All volatile data will be lost in this case also.
If the room EPO is not connected to the unit EPO, resetting the computer room unit EPO removes alternating current power from the system. If the interlock bypass feature is used, the system remains powered for a short time based on system configuration.