Airport Express

The AirPort Express is a Wi-Fi base station product from Apple Inc. While more compact and in some ways simpler than another Apple Wi-Fi base station, the AirPort Extreme, the Express offers audio output capability the Extreme lacks. The newer 802.11n models allow users to stream audio from a computer running iTunes or mobile device running iOS 5+ to a stereo system using a feature called AirPlay. When connected to an Ethernet network, the Express can function as a wireless access point. The current model allows up to 50 networked users. It can be used as an Ethernet-to-wireless bridge under certain wireless configurations. It can be used to extend the range of a network, or as a printer and audio server. The model introduced in June 2012 includes two Ethernet ports: one WAN and one LAN. ... The AirPort Express uses an audio connector that combines a 3.5 mm minijack socket and a mini-TOSLINK optical digital transmitter, allowing connection to an external digital-to-analog converter (DAC) or amplifier with internal DAC. [AirPort Express. Wikipedia]