Credit authorization system

Claim 2

A credit auThorization system for use in authorizing credit for a credit account holder presenting a credit account number at any of a plurality of remote authorization terminals, said system comprising: means for generating a signal constituting a repeating sequence of digitally encoded credit account numbers having credit authorization significance; central FM radio frequency transmitter means for transmitting said signal in the form of a modulated FM SCA subcarrier to said authorization terminals; means at each of said authorization terminals for receiving said subcarrier and for demodulating said subcarrier to retrieve said signal; digital comparator means at each of said authorization terminals for digitally comparing the credit account number presented at any of said authorization terminals with the significant credit account numbers of said sequence; and coincidence signalling means interconnected with the respective comparator means at each of said authorization terminals for indicating whether or not the presented credit account number coincides with any one of the significant credit account numbers of said sequence, whereby credit may be authorized for the presented credit account number according to indication of coincidence.

Claim 3

A credit authorization system as set forth in claim 1 further comprising memory means at each of said authorization terminals for electronically storing the presented account number for comparison by said comparator means with the significant credit account numbers of said sequence.

Claim 4

A credit authorization system as set forth in claim 2 further comprising means at each of said authorization terminals for signalling the absence of coincidence of the stored credit account number with the significant credit account number of said sequence.

Claim 5

A credit authorization system as set forth in claim 3 wherein said means for signalling the absence of coincidence comprises further memory means for electronically storing one of the credit account numbers of said sequence as it is received, said digital comparator means being operative also for digitally comparing said one credit account number stored in said further memory means with subsequently received credit account numbers of said sequence, and means for indicating coincidence of said stored one account number with a subsequently received credit account number of said sequence.

Claim 6

Apparatus for electronically determining coincidence of credit account numbers or the like , said apparatus comprising: means for receiving an FM radio frequency SCA subcarrier and for demodulating said subcarrier to detect a signal constituting a repeating sequence of serially encoded credit account numbers having special credit significance; first memory means for storing one of the numbers of said sequence as said signal is received; number selector means for selecting a predetermined credit account number for comparison thereof with credit account numbers of said sequence; second memory means for storing the selected credit account number; digital comparator means for comparing individual numbers of said sequence as said signal is received with the numbers stored in each of said memory means; means responsive to operation of the comparator means for signalling coincidence of the number stored in said second memory means with one of the numbers of said sequence, thereby to indicate that the selected credit account number is one of said credit numbers having special credit significance; and means responsive to operation of the comparator means for signalling coincidence of the number stored in said first memory means with one of the numbers of said sequence, thereby to indicate that the selected credit account number is not one of said credit account numbers having special credit significance.

Claim 7

Apparatus for electronically determining coincidence of credit account numbers or the like , said apparatus comprising: means for receiving an FM radio frequency SCA subcarrier and for demodulating said subcarrier to detect a signal constituting a repeating sequence of serially encoded credit account numbers having special credit significance; first memory means for storing one of the numbers of said sequence as said signal is received; number selector means for selecting a predetermined credit account number for comparison thereof with credit account numbers of said sequence; second memory means for storing the selected credit account number; digital comparator means for comparing individual numbers of said sequence as said signal is received with the numbers stored in each of said memory means; means responsive to operation of the comparator means for signalling coincidence of the number stored in said second memory means with one of the numbers of said sequence, thereby to indicate that the selected credit account number is one of said credit numbers having special credit significance; and means responsive to operation of the comparator means for signalling coincidence of the number stored in said first memory means with one of the numbers of said sequence, thereby to indicate that the selected credit account number is not one of said credit account numbers having special credit significance.

Claim 8

Apparatus as set forth in claim 5 wherein said signal is constituted by groups of binary characters defining said encoded credit account Numbers and further comprising cycling means for causing said digital comparator means to cycle alternately between binary comparison of the character groups defining numbers of said sequence with the number stored in said first memory means in binary form and comparison of the character groups defining numbers of said sequence with the number stored in said second memory means in binary form.

Claim 9

Apparatus as set forth in claim 6 wherein said cycling means comprises at least one bistable switching device.

Claim 10

Apparatus as set forth in claim 6 including synchronization means for causing operation of said digital comparator means in synchronization with said groups of characters of said signal.

Claim 11

Apparatus as set forth in claim 7 wherein said synchronization means comprises binary counter means interconnected with the cycling means and adapted to repeatedly count up to a predetermined number of counts dependent upon synchronization with said groups of characters of said signal.

Claim 12

Apparatus as set forth in claim 9 wherein said binary counter means is adapted to count to a first predetermined number of counts greater than the number of characters in each of said groups in the absence of synchronization with said groups of characters and to count up to a second predetermined number of counts equal to the number of characters in each of the groups when there is synchronization with said groups of characters.

Claim 13

Apparatus as set forth in claim 5 wherein each of said memory means comprises a random access memory having a plurality of binary bit locations for storing bits defining the stored numbers.

Claim 14

Apparatus as set forth in claim 11 including further binary counter means for controlling in which of said bit locations are stored the bits defining the stored numbers, said counter means being adapted to count up to a preselected number corresponding to the number of digits of said selected credit account number.

Claim 15

Apparatus as set forth in claim 11 wherein said number selector means comprises a keyboard adapted to be operated for generating bits for storage in ones of said bit locations.

Claim 16

Apparatus as set forth in claim 5 wherein said signal is constituted by binary data in serial form and further comprising means for converting the serial form data to parallel form for comparison by said comparator means.

Claim 17

Apparatus as set forth in claim 14 wherein said signal is constituted by groups of bits including a parity bit and further comprising parity check means responsive to said data and parity bit for inhibiting comparison by said comparator means if parity is incorrect.