A hand held data entry system (100, 100') has an ergonomic housing (102) including upper surface controls (104) which generate a first set of electrical signals, and lower surface controls (106) which generate a second set of electrical signals when operated independently. The first set of electrical...http://www.google.de/patents/US6288709?utm_source=gb-gplus-sharePatent US6288709 - Hand held data entry system
