The conversion isn’t just from analog to digital but also works the other way round - from the digital audio signals put out by your computer to the analog signals that will be audible from the headphones that you are using or the studio monitors that you have fixed. This sending of digital audio is facilitated through some sort of a connection - which can either be USB, Thunderbolt, FireWire or a specified PCI/PCIe card - which will be discussed in more detail as we move forward. Typically, an audio interface works by converting analog signals to digital audio information, which is the form that the computer will be able to process for results.
You can think of an audio interface as a very efficient middleman that will be able to connect all of your audio gear - including microphones and so on - to the computer that you are working on. Audio Interfaces Disadvantages What Is an Audio Interface?