Device for a digital arithmetic processing apparatus

A data entry device comprising:

• a keyboard device having a first keyboard terminal, at least one second keyboard terminal, and a third keyboard terminal;
• a plurality of keyboard switch means for selectively interconnecting said first, second, and third keyboard terminals;
• a semiconductor integrated circuit for cyclically providing at least first and second keyboard sampling pulses at different times with respect to each other;
• a first terminal pin;
• at least one second terminal pin;
• a third terminal pin;
• a first gate circuit through which said first terminal pin receives said first keyboard sampling pulses;
• a second gate circuit through which said at least one second terminal pin receives said second keyboard sampling pulses;
• an output-only lead connecting said first terminal pin and said first keyboard terminal for transmitting said first keyboard sampling pulses from said first terminal pin to said first keyboard terminal;
• an output/input lead connecting said at least one second terminal pin with said at least one second keyboard terminal, said output/input lead (1) for transmitting a said first keyboard sampling pulse from said at least one second keyboard terminal to said at least one second terminal pin when a said keyboard switch means is selected to interconnect said first keyboard terminal to said at least one second keyboard terminal during the occurrence of a said first keyboard sampling pulse, and (2) for transmitting said second keyboard sampling pulses from said at least one second terminal pin to said at least one second keyboard terminal;
• at least one timing-inhibition circuit having an input terminal connected to a said at least one second terminal pin for generating a key select signal only in response to said transmission of a said first keyboard sampling pulse to said at least one second terminal pin;
• and
• an input-only lead connecting said third keyboard terminal to said third terminal pin for transmitting said first keyboard sampling pulses to said third terminal pin when a said keyboard switch means is selected to interconnect said first keyboard terminal to said third keyboard terminal, and for transmitting said second keyboard sampling pulses to said third terminal pin when a said keyboard switch means is selected to interconnect a said at least one second keyboard terminal to said third keyboard terminal.