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Key code

  • US 4,432,142 A
  • Filed: 02/26/1982
  • Issued: 02/21/1984
  • Est. Priority Date: 02/26/1982
  • Status: Expired due to Term
First Claim
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1. A key reading system comprising:

  • a key having a plurality of rows, each row having a plurality of reading positions along its length, each reading position in one row cooperating with a reading position in each other row to form a cooperating set of reading positions, there being a plurality of such sets along the length of the key,each reading position being constructed with either a first physical characteristic or a second physical characteristic, except that no one of said sets has only second physical characteristics at every one of its reading positions,a key reading apparatus having reading means for reading the physical characteristics of the reading positions of each of said sets, taken in succession from the first set to the last set, said reading means including a clock line means for distinguishing the presence of each set at the reading means, said clock line means being responsive to distinguish the presence of a set, in response to a reading of any combination of first or second physical characteristics except all second physical characteristics.

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