The Power function for this button is for toggling the server power on or off. Sleep function is for use with ACPI-compatible operating systems. The function for this button is determined in the BIOS Setup utility of the motherboard.

In the center of the button is an LED for function status. A continuous green light indicates the server has power applied to it. A blinking green light indicates the server is sleeping. No light indicates the server does not have power applied to it (other than the 5 volt standby power).

The Power LED sleep indication is maintained on standby by the chipset. If the server is powered down without going through BIOS, the LED state in effect at the time of power off is restored when the server is powered on (until the BIOS clears it). If the server is not powered down normally, it is possible that the Power LED will be blinking at the same time that the System Status LED is off due to a failure or configuration change that prevents the BIOS from running.