The input devices supply data needed for calculation as well as the program that tells the computer how and what to do with the data. The standard input units are:
(i) The keyboard
(ii) mouse
(iii) scanner
(iv) Digital camera
(v) CD drives
(vi) Magnetic disk
(vii) Tape drives
(viii) Joystick
(ix) Voice recognition
(x) Microphone
Note that all inputs to the computer must be in the digital domain, that is, in binary form. Hence the need to convert analogue to digital form.