05534860 is referenced by 12 patents and cites 4 patents.

An apparatus for and method of scanning a key array (101-116) uses two or three scan lines (134 and 135 or 308, 309, and 310), thereby limiting the need for an excessive number of input/output lines of a processor (136). A separate resistor ladder (301,302, 303) is provided for each dimension of keys, including row, column, and/or matrix. A minimal number of parts is also required to implement the resistor ladder (301,302, 303). A reference conductor (311), a row conductor (312), a column conductor (313), and, if desired, a matrix conductor (314) each run under each key, such that when a different key is depressed, a unique combination of voltages appears at the scan lines (134 and 135 or 308, 309, and 310) for the resistor ladders (301, 302, 303).

Title
Multiple key array
Application Number
8/236797
Publication Number
5534860
Application Date
May 2, 1994
Publication Date
July 9, 1996
Inventor
Steven S Lee
4214 Devonshire Ct., Northbrook, 60062
IL, US
John J Oskorep
9132 Stratford La., Palos Hills, 60465
IL, US
Joseph E Phillips
11709A Davey Dr., Huntley, 60142
IL, US
Agent
Susan L Lukasik
IPC
H03M 11/20
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