Patent ID: RE41017

Claim:
A key switch signal recognition circuit comprising: a plurality of key switch buttons, said key switch buttons each provided with an electrically conductive element; a plurality of key switch key signal output lines; an AND gate having an output and a plurality of inputs respectively connected to said plurality of key switch key signal output lines; and a plurality of contact areas arranged on a substrate corresponding to said key switch buttons, said contact areas each comprising a first wire set and a second wire set, said first wire set comprising at least one wire having one end connected to a common line and an opposite end forming an open end, said second wire set comprising at least one wire respectively disposed in parallel to and electrically insulated from the wire of said first wire set, the wire of said second wire set being respectively connected to the key switch signal output line which is selected subject to a predetermined bit encoding mode; when one of said key switch buttons is depressed to touch the corresponding contact area, the electrically conductive element of the depressed key switch button electrically connects the first wire set and second wire set of the touched contact area, causing the respective key switch signal output line to send a key switch signal corresponding to the depressed key switch button, said output of said And AND gate outputting a triggering signal responsive to the key switch signal output line of a corresponding contact area is at a logically high level.