Apparatus for calculating a check digit for a stream of data read from a document
First Claim
1. A document processing system comprising:
- a reader sorter for reading characters sequentially from a document and generating character signals indicative of a starting character of a field, a closing character of said field, and a plurality of numeric characters within said field, said plurality of numeric characters including a check digit character and a plurality of decimal digit characters;
an adapter coupled to said reader sorter and responsive to said character signals representative of said plurality of decimal digit characters for generating a plurality of position count signals indicative of a position of each of said plurality of decimal digit characters in said field, said adapter including a memory unit responsive to said character signals indicative of said plurality of decimal digit signals and a corresponding one of said plurality of position count signals for generating a plurality of product signals, each representative of the units position of the result of the multiplication of said one of said plurality of decimal digit characters by one of a plurality of predetermined numbers as indicated by said corresponding one of said plurality of position count signals; and
,a microprogrammed controller coupled to said reader sorter and to said adapter and including a control store responsive to said character signals indicative of said starting and said ending characters for generating a first and a second plurality of control signals, said adapter being responsive to said first plurality of control signals for generating said plurality of product signals,said controller including an arithmetic logic unit responsive to said second plurality of control signals and said plurality of product signals for generating signals indicative of said calculated check digit characters, and being further responsive to said character signals indicative of said check digit character for comparison with said calculated check digit characters.
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Abstract
Information from a document is read by a reader sorter; the information is organized in fields including a transit field which is made up of 8 decimal digits and a check digit. The 8 decimal digits are each multiplied by a predetermined number which depends on the position of the decimal digit in the transit field as indicated by a position counter. Signals indicative of the decimal digit and the position in the transit field are applied to the address terminals of a Programmable Read Only Memory (PROM). Each address location stores the units position of the product of the multiplication of the decimal digit times the predetermined value. A firmware routine stored in a control memory performs the check digit calculation "on the fly" using the units position of the product from the PROM and certain status bits stored in a scratchpad memory.
36 Citations
8 Claims
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1. A document processing system comprising:
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a reader sorter for reading characters sequentially from a document and generating character signals indicative of a starting character of a field, a closing character of said field, and a plurality of numeric characters within said field, said plurality of numeric characters including a check digit character and a plurality of decimal digit characters; an adapter coupled to said reader sorter and responsive to said character signals representative of said plurality of decimal digit characters for generating a plurality of position count signals indicative of a position of each of said plurality of decimal digit characters in said field, said adapter including a memory unit responsive to said character signals indicative of said plurality of decimal digit signals and a corresponding one of said plurality of position count signals for generating a plurality of product signals, each representative of the units position of the result of the multiplication of said one of said plurality of decimal digit characters by one of a plurality of predetermined numbers as indicated by said corresponding one of said plurality of position count signals; and
,a microprogrammed controller coupled to said reader sorter and to said adapter and including a control store responsive to said character signals indicative of said starting and said ending characters for generating a first and a second plurality of control signals, said adapter being responsive to said first plurality of control signals for generating said plurality of product signals, said controller including an arithmetic logic unit responsive to said second plurality of control signals and said plurality of product signals for generating signals indicative of said calculated check digit characters, and being further responsive to said character signals indicative of said check digit character for comparison with said calculated check digit characters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification