A keypad system operates in a first mode or a second mode. Each key cap is coupled to each group of adjacent two key switches. Each of first symbols is disposed on each of key caps. Two of each second symbols which is rotated 90 degrees to the first symbols are disposed over each key cap, and each of...http://www.google.fr/patents/US20050219067?utm_source=gb-gplus-shareBrevet US20050219067 - Portable telephone keypad
