Patent US 6,943,776

A manual input system for efficient generation of inputs by entering chords comprises a keyboard (66) with ten colored keys (74, 76, 78, 80, 82, 84, 86, 88, 90, and 92) and a legend (94) The keys of the keyboard (66) each are operated by a different digit of a human operator and each have a different color. The legend (94) presents the assignment of chords to the symbols found on the standard computer keyboard. Character chords involve only fingers, while modifier chords involve only thumbs, so that each character can be combined with each modifier. Command chords also involve a thumb, so that accidental input of modified characters and commands during character input is prevented. The legend (94) shows determination of chords by visualizing the position of symbols relative to the rows. Chords are represented by combinations of digit-representing colored area. Each colored area resembling a digit or colored keys.