If you have or are wanting equipment that requires a MIDI connection, it may be worth investing in an audio interface that offers both MIDI in/out ports, so you have the option to connect your MIDI device to your computer. Another point to consider is MIDI connectivity. Many modern interfaces offer practical ‘combo’ inputs that accept both XLR and 1/4-inch jack cables. For a basic recording set-up, it’s unlikely that you'll need more than one mic input for vocals and one instrument/line-level input. You’ll need an audio interface if you want to record external audio into your computer.
Audio Interfaces also work in reverse, by converting digital signals from your computer into analogue signals for playback over your loudspeakers or headphones.
It converts analogue signals into digital signals so they are compatible with your computer software for recording.
This is a device used to connect your audio sources (microphones, guitar, keyboard etc.) to your computer.