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Encodable Security Lock

IP.com Disclosure Number: IPCOM000078070D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Shutler, WF: AUTHOR

Abstract

Described is a device for providing a security lock for peripheral devices, terminals, etc. This device responds to one and only one unique address (or key) and utilizes a personalizable element, which enables permanent electronic encoding of information at the finished module level. Thus, only one master slice is needed in production.

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Encodable Security Lock

Described is a device for providing a security lock for peripheral devices, terminals, etc. This device responds to one and only one unique address (or key) and utilizes a personalizable element, which enables permanent electronic encoding of information at the finished module level. Thus, only one master slice is needed in production.

The circuit comprises a "n" position shift register, two buses ('1' test and '0' test) and an AND circuit, as shown in Fig. 1. Each stage of the shift register has a programmable connection, not shown, to each "test" bus. Either the 1 or 0 connection is made, never both. Both may be left open, however, for a "don't care" condition. The 'n' bit key is read into the registers in serial fashion. If the key presented agrees exactly with the encoded personality, the "enable" output becomes active and unlocks the device for operation. Although serial data input is shown, parallel data input is equally feasible.

One typical bipolar implementation is shown in Fig. 2.

Operation is as follows: The cell shown is encoded to accept a 1. (Q=+,Q = -). This means that element F2 is shorted. If the cell contains a 0, Q is down and Q is positive. Therefore, T2 conducts which pulls current from the clamp, resulting in the enable output being negative. If the cell contains a 1, Q is up and Q is down. T1 attempts to conduct, but since element F1 is effectively open, no current is pulled from the clamp and the enable output lines...