Dell 320 manual Back View, See Back-Panel Connectors for details

		different operating states:
		• No light — The computer is turned off.
		• Steady green — The computer is in a normal operating state.
		• Blinking green — The computer is in a power-saving mode.
		• Blinking or solid amber — See Power Problems.
		To exit from a power-saving mode, press the power button or use the
		keyboard or the mouse if it is configured as a wake device in the
		Windows Device Manager. For more information about sleep modes and
		exiting from a power-saving mode, see Power Management.
		See System Lights for a description of light codes that can help you
		troubleshoot problems with your computer.
9	headphone	Use the headphone connector to attach headphones.
	connector
10	LAN indicator	This light indicates that a LAN (local area network) connection is
	light	established.

Back View

1	cover release	This latch allows you to open the computer cover.
	latch
2	padlock ring	Insert a padlock to lock the computer cover.
3	power	Insert the power cable into this connector.
	connector
4	voltage	Your computer is equipped with a manual voltage-selection switch. To
	selection	help avoid damaging a computer with a manual voltage-selection switch,
	switch	set the switch for the voltage that most closely matches the AC power
		available in your location.
		NOTICE: In Japan, the voltage selection switch must be set to the 115-V
		position.
		Also, ensure that your monitor and attached devices are electrically rated
		to operate with the AC power available in your location.
5	back-panel	Plug serial, USB, and other devices into the appropriate connector.
	connectors	See Back-Panel Connectors for details.
6	card slots	Access connectors for any installed PCI and PCI Express cards.

Back-Panel Connectors