A computer headset is dual function device for communication between the user and the machine. Headphones come with two parts, one is an input device called as the mic or microphone, whose job is to take the user voice or the sound from the player to the computer through a microphone wire. The second device is the output device called as speakers whose function is to deliver the sound from the computer to the player. So in a nutshell, a headset is a two function device packed into a small gadget which is wearable on the head, this is the reason it is called as a headset.