This chapter discusses the principles of audio routing and broadcasting in the context of television along with the important means of synchronization needed. In analog routing, the router and associated cabling can affect the signal quality. The advantage of digital routing is that only data are being transmitted and so the transmission and routing process can be transparent. In a digital router the input audio signal is sliced and phase locked back to a clean square binary signal so that the routing process itself is carried out on logic levels. The serial digital interface (SDI) is becoming increasingly popular in television production installations for routing digital video signals. In analog broadcasting, multipath transmission is a serious problem. In digital broadcasting, effectively the channel between the transmitter and the viewer is a multiplexed data link in which some of the data represent picture information and some represent audio.