This chapter offers an introduction to various ways in which digital audio data can be communicated between devices over dedicated interfaces, data interconnects, or networks. In the early days of digital audio, when using dedicated audio products rather than computer industry technology adapted for audio purposes, such communication was usually done using dedicated digital audio interfaces. Digital audio interfaces are real-time, point-to-point wired connections that allow a number of channels of digital audio data to be transferred between devices with no loss of sound quality. There are three types of communication: audio control, audio streaming, and MIDI streaming. Essentially an ATM connection is established in a similar way to making a telephone call. A SETUP message is sent at the start of a new ‘call’ that describes the nature of the data to be transmitted and defines its vital statistics.