Patent GB-1336133-A (GB)
Title: Access-control equipment and item-dispensing systems including  such equipment
IPC: G07F19/00
Filed: 1970-08-25
Abstract: 1336133 Token freed device SMITHS INDUSTRIES Ltd 25 Aug 1970 [25 Aug 1969] 40867/70 Divided out of 1336131 Headings G4X G4V G4M and G5X Equipment for controlling access to a facility comprises means for reading a word from a token inserted in the equipment, means for entering another word into the equipment, encyphering means (Fig. 3) for deriving a translated word digit-by-digit from a first of said words, successive digits depending through feedback on the previously derived ones, and comparator means for comparing a second of said words with the translated words to inhibit the access if a predetermined correspondence is not detected. As described in detail in the Parent Specification 1,336,131, the equipment is employed as a banknote dispenser, each customer having a token that bears an embossed personal-identification number. Encyphering unit.-In operation, the personal-identification number is read from an imprinted record of the embossings by a head 34 (Fig. 3) and fed to a converter 51, which converts each digit successively into a four-bit binarycoded decimal word. The first four-bit word is received in a shift-register 54 and transmitted into a twenty-five stage shift-register 56 by four successive pulses of a clocking unit 55. The initial state of the shift-register 56 was determined by an entry-program unit 57. Signals from the stages I to XXIV of the shift register 56 are jumbled together by cross-connections in a feed-through program unit 58, and recombined in six sets of four-digit numbers. The numbers are added in pairs by adders 59-61, with carry forwards between the adders. Two digits from adder 59 and one digit from each of adders 60, 61 are fed back through a gate 53 to be added by an adder 52 to the second four-bit word received from the head 34. When all four-bit words from the head 34 have been similarly processed, the number stored in the shift register 56 bears a complex and unique relationship to the customer's personal identification number. At this stage, the customer is requested to key in a code number on push-buttons 42, the digits being fed successively in four-bit binary-coded decimal form to a comparator unit 39. On receipt of the first four-bit word, the clocking unit 55 produces four pulses to transfer the contents of shift register 54 into shift register 56. Thereafter, shift register 54 contains the sum through gate 53 of a word formed from the stages XXII to XXV of shift register 56, with the word fed back from the adders 59-61. The new word formed from adders 59-61 passes through a gate 62, that changes the most-significant digit under certain circumstances, to a comparator unit 39, wherein it is added to the first four-bit word of the keyed in code number. The process is repeated for each word of the code number, and the correspondence is signalled as acceptable if the result of each sum in the unit 39 is '1111". Finally, the circuit is returned to its initial state by the entry-programme unit 57. The equipment is claimed more broadly in Specification 1,336,134 divided herefrom. Reference has been directed by the Comptroller to Specification 1,197,183.