The screen of a phone and tablet is an input and output device. You input on the screen through touch, and it outputs through graphics.
Game system: gamepads, joysticks, and specialized gaming keypads. These devices are all designed to control your in-game character, vehicle, animal or widget. The output would basically be the response feedback.
Digital assistant: the input is the control buttons. the output are the signals or data sent from it and or the screen.
Hope this helped:)
