United States Patent 3,892,958
Inverse/Complementary Function Prefix Key
July 1, 1975
Inventor: Chung C. Tung, Santa Clara, Calif.
Assignee: Hewlett-Packard Company, Palo Alto, Calif.
Filed: Jan. 11, 1974
Appl. No.: 432,736
Abstract:
A hand-held programmable calculator is specified, which has a prefix key for
designating the inverse or complement of direct functions having legends on
the keyboard thereof, thus expanding the utility of the keys on the keyboard.
9 Claims, 1 Drawing Figure
Eric's notes:
This patent describes the HP-65.
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