On some newer laptops, the microphone and headphone ports are combined, so the headphone jack is also the microphone jack. This makes it work with in-line micro

On some newer laptops, the microphone and headphone ports are combined, so the headphone jack is also the microphone jack. This makes it work with in-line microphones that are popular with most cell phones. I don't understand what he hopes to accomplish by taping the jack though; it's not like it does anything without something plugged into it.