IEC 5007, the power on (line) symbol, appearing on a button or one end of a toggle switch indicates that the control places the equipment into a fully powered state. It comes from the binary system (1 or | means on)
IEC 5008, the power off (circle) symbol on a button or toggle, indicates that using the control will disconnect power to the device. It comes from the binary system (0 means off)
IEC 5009, the standby symbol (line partially within a broken circle), indicates a
sleep mode or low power state. The switch does not fully disconnect the device from its
power supply. This may appear on a toggle switch opposite a power on symbol, alone on a pushbutton that places the device into a standby state, or alone on a button that switches between on and standby. Alternatively, under
IEEE 1621, this symbol simply means "power".
IEC 5010, the power on-off symbol (line within a circle), is used on buttons that switch a device between on and fully off states.
Every one is right on the money today. I like it when we all come to the same answer from different angles.
