A MIDI interface is a device that allows electronic musical instruments, computers, and other audio equipment to communicate with each other using the MIDI (Musical Instrument Digital Interface) protocol. It converts MIDI data into a format that can be understood by different devices, enabling musicians to control synthesizers, drum machines, and software applications seamlessly. These interfaces can be hardware-based, connecting via USB or traditional MIDI ports, or software-based, functioning within a computer's operating system. By using a MIDI interface, musicians can record, edit, and play back music more efficiently, enhancing their creative possibilities in music production.