Apple AirPort Express 5.1 - Manual (Page 19)

Chapter 2 Using AirPort Express 19
You can also connect your AirPort Express to the Internet and provide Internet access
to computers that join the network. Connect your AirPort Express to your home stereo,
and computers on the network with AirPort Extreme Cards or computers with
compatible 802.11b or 802.11g cards can use iTunes to play music on the stereo.
DSL or cable
modem
to Internet
Stereo
receiver
Line Out port Ethernet port