The term channel is used to describe several related components of a Pro Tools | First system.

The first example of channel refers to a physical input or output of your Pro Tools | First system. The second use of the term channel refers to a channel strip in the Mix window. Each track in a Pro Tools | First project has a corresponding channel strip in the Mix window.

Audio and MIDI channel strips have similar controls, but those controls have slightly different effects. For example, audio, Auxiliary Input, and Instrument track channel strip faders control the output gain to the mix bus for that channel, while MIDI channel strip faders send MIDI volume data (MIDI controller 7) to the selected MIDI instrument.