Determining the Value of the Check Digit

Weighting Factor

The weighting factor is a method of subjectively increasing the relative importance of one item over another. Each numerical equivalent is multiplied by a weighting factor in the range 2^0 to 2^9. The weighting factor 2^0 is applied to the first letter of the owner code, and then in increasing powers of 2, rising to 2^9 for the last digit of the serial number.

Value of the Check Digit

This table indicates the check digit value corresponding to the remainder value of division effected in conformity with 0. To avoid the duplication resulting from the value zero being assigned as a remainder of both 10 and 0, we recommend that serial numbers resulting in remainders of 10 should not be used.

Remainder	Check Digit
10	0
9	9
8	8
7	7
6	6
5	5
4	4
3	3
2	2
1	1
0	0

The serial number is restricted to the digits 0-9.

Sample Calculation

This example shows a sample owner code, equipment category ID, and serial number, and then provides equivalent and weighting factors for each letter and numeral. The last table shows the product of the columns in the Equivalent Factors table and the Weighting Factors table.

Owner Code = ZEP

Equipment Category ID = U

Serial Number = 003725

Full ID
Z	E	P	U	0	0	3	7	2	5

Equivalent Factors
38	15	27	32	0	0	3	7	2	5

Weighting Factors
1	2	4	8	16	32	64	128	256	512

Product of columns in Equivalent Factor and Weighting Factors
38	30	108	256	0	0	192	896	512	2560

The sum of all the products in this table = 4592

The sum divided by the modulus 11 = 417 5/11

The remainder is 5. See the Value of the Check Digit table above to determine that the check digit is 5 in this case.