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Keyboard arrangements

  • US 4,675,653 A
  • Filed: 11/06/1985
  • Issued: 06/23/1987
  • Est. Priority Date: 11/10/1984
  • Status: Expired due to Fees
First Claim
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1. A keyboard arrangement including a keyboard and associated apparatus for receiving input data from the keyboard, the keyboard comprising a first set of keys and a second set of keys;

  • a main power source for supplying power to the arrangement during normal operation;

    first scanning means operable only during said normal operation to scan and detect the operation of any of the keys in said first and second sets, the first scanning means being rendered operative by a signal derived from the main power source;

    a standby power source for supplying power to the arrangement in the event of interruption of the power from the main power source, andsecond scanning means operable only when the standby power source is in operation to scan and detect the operation of any of the keys in said second set only, the second scanning means being rendered operative by the absence of said signal when power from the main power source is interrupted.

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