Fiscal data recorder programmed to write only non-blank values to memory
First Claim
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1. A fiscal data recorder for storing transaction related data, comprising:
- a processing unit receiving transaction related data;
memory communicating with said processing unit for storing said transaction related data; and
a protection circuit acting between said processing unit and said memory, said processing unit being programmed to write only non-blank values to said memory; and
said protection circuit including a store to hold data to be written to said memory and a comparator to determine whether a block in said memory to which the held data is to be written is blank, data in said store being passed to said memory only when said memory block is blank thereby preventing data stored in said memory from being overwritten.
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Abstract
A fiscal data recorder for storing transaction related data in a point of sale system is provided with a processing unit receiving the transaction related data. Memory in communication with the processing unit is operable to store the transaction related data. A protection circuit acting between the processing unit and the memory inhibits the electronic tampering with the transaction data stored in the memory.
30 Citations
16 Claims
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1. A fiscal data recorder for storing transaction related data, comprising:
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a processing unit receiving transaction related data; memory communicating with said processing unit for storing said transaction related data; and a protection circuit acting between said processing unit and said memory, said processing unit being programmed to write only non-blank values to said memory; and said protection circuit including a store to hold data to be written to said memory and a comparator to determine whether a block in said memory to which the held data is to be written is blank, data in said store being passed to said memory only when said memory block is blank thereby preventing data stored in said memory from being overwritten. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A fiscal data recorder for storing transaction related data, comprising:
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a main circuit board; a processing unit mounted on said main circuit board for receiving transaction related data; memory coupled to said main circuit board for storing transaction related data; a protection circuit for controlling access to said memory and inhibiting data stored in said memory from being overwritten, said processing unit being programmed to write only non-blank values to said memory; and a tamper-proof seal inhibiting physical access to said memory and said protection circuit; and said protection circuit including a store to hold data to be written to said memory and a comparator to determine whether a block in said memory to which the held data is to be written is blank, data in said store being passed to said memory only when said memory block is blank thereby preventing data stored in said memory from being overwritten. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification