An interface serves two purposes: input (ADC) and output (DAC). Simply put, an interface takes in voltage signals sent to it and converts them into a digital signal (Analog to Digital Conversion - ADC) to be used in your computer. It also takes digital signals from the computer and outputs them as a voltage to your speakers and/or headphones (Digital to Analog Conversion - DAC). Some interfaces also have computing power for the brand specific plugins available to your DAW (more on that later).

Be aware of the data transfer cables needed. You may have to verse yourself on the different types of connections used and needed for interfaces. Some USB-C connections are just now being adopted by certain brands, so some PCs and laptops won't be able to connect directly to some connection types. For example, UAD interfaces use Intel based USB-C for processing the UAD bundle plugins, but AMD motherboards are just now adopting the version of USB-C used for UAD interfaces

Many beginner level interfaces use simple USB connectors, so luckily that makes things easier. If you’re using a Mac you may need to use a USB-C to USB adapter.

Most interfaces have a basic built in preamp, and some will have a built in DI preamp. These are indicated by the connection types, an XLR is a three pin input and a DI is a ¼ inch plug input. In the preamp section, you should have a gain control knob. This allows you to adjust the input loudness and is usually labelled “gain” or “input”.

Features to look out for that are built into basic ADC/DAC interfaces:

• If you’re using a condenser mic, you’ll need phantom power. This is indicated with a “+48v” button. The +48v phantom power should be turned off when the mic is not in use (but is still plugged in). It should be turned off prior to unplugging the cable. If you unplug with the phantom power still turned on, you risk creating a very loud pop in the output, but you're also slowly putting wear on the electrical system, so be mindful of your +48v button.

• Another good feature to have is a PAD (Passive Attenuation Device). A pad is a built in attenuator, meaning engaging the pad button will turn the signal down by a fixed amount, usually -10dB. This is indicated in a number of ways, usually “PAD” or “-10”.

• Some interfaces may include a high pass filter. This is indicated by a horizontal line that angles 45 degrees down on the left side. This is a good feature that cuts some of the low frequencies to counteract the “mud” or “proximity” that comes from dynamic microphones. This is good for streamers and podcasters.

• Input Phase Reversal may be something to look out for if you have more than one XLR input. You’ll see this indicated with a symbol of a circle with a line diagonally passing through it. Phase reversal used when you’re using two or more mics on the same sound source. There is a whole world of physics based around phase but that won’t be necessary in a beginners guide. It’s a good but not necessary feature to have when starting.

• For beginners interested in mixing it doesn't hurt to look for a “MONO” button. This will take your left and right stereo output and combine the signal to play equally through both of your speakers, allowing you to further check and improve your phase. It's not necessary but it's a nice thing to have.