Apple Setting Up Your Power Macintosh G4 (PCI & AGP) - Manual (Page 21)

Setting Up 21
2 If the monitor power button doesn’t start up the computer, press the power button (
®) on
the front of the computer.
You can also press the power button (
®) on the Apple USB keyboard.
Note: The Apple USB keyboard power button works only if the keyboard is connected to
one of the computer’s built-in USB ports.
Computer power button