Keyboard switching system for data processing machine - has cyclic span of key rows producing signal codes of depressed keys

摘要

Keyboard switching system for operating a data processing unit. This electronic keyboard uses hardware in conjunction with simplified input circuits. The input circuits will determine the validity of the key code information. The key code consists of rows and columns of keys identified by coordinates. The rows of the keys are scanned cyclically in a predetermined order. This suppies parallel key code information corresponding to each key. There are cut-out elements which detect depressed keys during two sequential test cycles to produce cut out signals. Certain elements will react to these signals to read and store to key code information associated with the keys depressed.