Digital technology transforms analog signals into digital signals. Digitalization translates data into a numerical sequence of 0 seconds and 1 second or off and on (binary system). Thus encoded, differing signals (static or moving images, sounds, written texts) become homogeneous and can be handled simultaneously in a rapid and flexible manner while maintaining quality and stability. In digital format, data are easy to handle and can be compressed without undergoing any alteration of their contents, creating a vast wealth of information contained in little space, as in digital libraries.