A chordal keyboard method and apparatus for generating a key code using a plurality of keys coupled to a controller with a first set of registers and a second set of registers. A user depresses at least one of the plurality of keys. The controller detects, which of the plurality of keys are in a depressed...http://www.google.fr/patents/US5189416?utm_source=gb-gplus-shareBrevet US5189416 - Chordal keyboard method and apparatus
