Patent ID: 6288652
Filing Date: 2001-09-11
Classification: H03M

Abstract:
A keypad apparatus comprising:a first switch, a second switch, a third switch, a fourth switch, and a fifth switch, each switch having a first and a second node, wherein each switch has a pressed position and a released position and the switches are normally in the released position;a reference terminal; andthree sense terminals defining an output code having eight values, wherein the first node of each switch is connected to the reference terminal and the second node of the each switch is connected to at least one sense terminal, if a second node is connect to more than one sense terminal the connection is through a diode, the second nodes connected such that five output code values are respectively generated in response to pressing each switch individually, a sixth value when all five switches are released, a seventh value when a first predetermined pair of switches are pressed simultaneously, and an eighth value when a second predetermined pair of switches are pressed simultaneously.