DIN connectors
DIN connectors are used for a variety of applications in audio and computer devices. They come in a number of pin configurations (2, 5, 6, 7, 8) and in both standard and mini sizes.

In computer applications DIN plugs can be used as keyboard/mouse connectors and the 5-pin DIN version is typically used for connecting MIDI devices together.

In audio applications (including public address) these are mainly used for microphone priority acess on some public address amplifiers - there are a number of different ways that they can be wired for various functions, it is best to refer to the installation guide for specific models.