A protocol that transmits control messages between devices and software, carrying no audio itself.
MIDI (Musical Instrument Digital Interface) is a communication protocol that sends discrete event messages, such as a button press, a knob position change, or a note-on command, between hardware controllers, computers, and software. It transmits control data only, never audio: a MIDI cable or USB MIDI connection tells software what to do but does not carry any sound.
Why it matters
MIDI is the universal language that lets a DJ controller, pad controller, or custom button box communicate with DJ software. Understanding that MIDI carries messages rather than audio clarifies why a USB cable connecting a controller to a laptop routes MIDI data while the audio output still requires a separate connection to speakers or a mixer.
In practice
When troubleshooting a controller that stops responding, check the DJ software's MIDI input list first: if the controller does not appear as a MIDI device, the issue is at the driver or USB connection level, not inside the software's mapping.
