There is a multi-function button on the cable of your SuperFi 5vi earphones.
This is a multi-function button that typically can be used to perform the following functions:
While music is playing: The button can be used to pause and resume the music.
During incoming call: The button can be used to answer the call.
During a call: the button can be used to hang up the current call.
NOTE: The function of the button depends if your music player or phone supports the button, and how your phone or music player is designed to use the button.