Control keyboard with switches of mechanical constructions

A keyboard wherein each key is provided with a magnetic biasing means for urging the same back to a rest position and is operatively coupled to at least one single-pole switch, each switch comprising a movable contact part including two conducting elements electrically insulated from each other and wherein said switches are electrically connected to a system of conductors arranged in a matrix-like array with m rows and n columns, each row and each column being carried out as a conductor so that any switch having the coordinates i, j is connected between the row i and the column j of said system and adapted in the rest position of the switch to contact in engaging relationship, two terminals electrically connected to the corresponding conductors of the row and of the column of said system and a diode-like element associated with said switch being connected across both conducting elements, wherein the improvement consists in that each of said switches is of the normally closed contact type and comprises a diode-like element, said diode-like element being inserted within an insulating portion of said switch, said insulating portion forming an anchoring support keeping both conducting elements spaced from each other, said diode-like element being connected in series within the switch, the direction of connection of all said diodes being the same between the rows and the columns.