Nortel DMS-100 TOPS Domestic Credit Card Check Digit Table (CHKDIGIT)

Table Name

Traffic Operator Position System Domestic Credit Card Check Digit Table

Functional Description of Table CHKDIGIT

Table CHKDIGIT performs a special digit check that compares one of the last four digits of the 14-digit domestic credit card or portable special billing number against a designated check digit in the number.  The last four digits are of the format XXXX, representing a Personal Identification Number (PIN) with any one of the four digits designated a check digit (specified in field CHKDGPOS).

Each year, the seventh, eighth, ninth, or tenth digit is designated as the check digit and a number (0 to 9) is assigned to each of the numerics 0 to 9 to which the check digit may be equal.  A valid credit card or special billing number is one that has the correct value in XXXX to match the value of the check digit.  When the match is found during the special digit check the DMS Traffic Operator Position System (TOPS) proceeds to the next check.

Conversely, a mismatch indicates an invalid domestic credit card or special billing number.  If this occurs, the credit card number shown on the TOPS flashes off and on to notify the TOPS operator of the mismatch.

As of BCS9, two other tables (RAOCHECK and NPACHECK) are used to define RAOs and Numbering Plan Areas (NPA) to be checked using table CHKDIGIT.  For related information, refer to table HOTLIST (TOPS Domestic Hot List).

Datafill Sequence & Size

There is no requirement to datafill other tables prior to table CHKDIGIT.  Table size is 0 to 2 tuples.

Datafill

The following table describes datafill for table CHKDIGIT:

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Table CHKDIGIT Field Descriptions

Field       Subfield       Entry                     Explanation and Action
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PERIOD                     PRESENT or PREVIOUS       Period
                                                     Enter PRESENT or PREVIOUS to specify the 
						     year to which the special digit check 
						     applies.

                                                     At the end of each year, transfer the 
						     information in the PRESENT record to the
						     PREVIOUS record, then enter the 
						     information that applies to the new year
						     in the PRESENT record.
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VERDGPOS                   7 to 10                   Verification Digit Position
                                                     Enter the position of the verification 
						     digit.
----------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------
CHKDGPOS                   11 to 14                  Check Digit Position
                                                     Enter the position of the check digit.
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VAL0 to VAL9               0 to 9                    Value
                                                     Enter in fields VAL0 to VAL9 the value 
						     that the Nth digit of the credit card or 
						     special billing number must be when the 
						     value of the check digit is equal to 0 
						     to 9, where 'n' is the entry in field 
						     CHKDGPOS.
----------------------------------------------------------------------------------------------
-End-

Datafill Example

The following example MAP display shows sample datafill for table CHKDIGIT.

The 14th digit of the present year credit card or special billing number must be equal to 2, 1, 5, 6, 0, 9, 7, 4, 3, or 8 when the 7th digit of the present year credit card number is equal to 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 respectively.

The 11th of the 14-digit previous year credit card or special billing number must be equal to 5, 9, 2, 7, 1, 4, 0, 6, 8, or 3 when the 9th digit of the previous year credit card number is equal to 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 respectively.

Note:  41444453333338 is an invalid present year credit card number because its 7th digit is equal to 5, and in PRESENT period, the entry in field CHKDGPOS is 14, indicating that the last digit of the credit card number is the check digit and its value (8) should match the value of VAL5, which is 9.


PERIOD   VERDGPOS  CHKDGPOS  VAL0  VAL1  VAL2  VAL3  VAL4  VAL5  VAL6  VAL7  VAL8  VAL9
_______________________________________________________________________________________
PRESENT         7        14     2     1     5     6     0     9     7     4     3     8
PREVIOUS        9        11     5     9     2     7     1     4     0     6     8     3