Method to Provide Numeric Keypad Functions on a Keyboard
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
A method is described to make the keypad function and dedicated cursor keys on a keyboard of a Personal Computer (PC) transparent to application programs for compatibility requirements. The IBM Personal Computer family of products has established a keyboard layout where 14 outboard keys function as either numeric keypad keys or as cursor keys. The numeric keypad keys consist of the 0-9,+,-,* and . keys. The cursor keys are overlayed on the same keys with the Cursor Left, Right, Up, Down, Home, Page Up, Page Down, and End keys. The PC family of products designed the keypad area to be selectable between cursor functions and numeric functions with the addition of a third key called Num Lock. Each time a key is pressed on a keyboard, the hardware generates a unique code for that key, called a scan code.