Worth Data 7100 RF Terminal Series, Owner'S Manual

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The UPC/EAN checksum character
The last character in a UPC-A, UPC-E, UPC-E1, EAN-13 or EAN-8 bar code is the checksum. For reference, these are the meth-
ods of calculation:
Checksum calculation for UPC-A, EAN-13 and EAN-8
Use Worth Data's phone number (it's not a real UPC-A code) as sample data:
18314589938
Assign even and odd positions, starting at the right and moving left:
8 3 9 9 8 5 4 1 3 8 1
odd even odd even odd even odd even odd even odd
Starting with the leading digit, 8, take the sum of all the characters in the odd positions.
8 + 9 +8 + 4 + 3 + 1 = 33
Multiply the result of step 1 by 3.
33 x 3 = 99
Now take the sum of all the even-position characters.
3 + 9 + 5 + 1 + 8 = 26
Add the result in Step 2 to the result in Step 3.
99 + 26 = 125
Subtract the result from the next higher multiple of 10.
Next higher multiple of 10 over 125 = 130
130 - 125 = 5
5 is the Modulo-10 check character. The data to be printed becomes:
183145899385
.
This same formula is used for EAN-13 (using the 1-12 digits) and EAN-8 (using the 1-7 digits).
UPC-E Checksum Calculation
Use the sample data of 123456 to demonstrate the UPC-E checksum calculation:
The 6 digit UPC-E code is converted to a 10-digit code, using an expansion scheme based on the sixth digit:
If the code
ends in:
UPC-E Data Insertion Digits Insertion
Position
10 digit code
0 abcde 0 00000 3 ab 00000 cde
1 abcde 1 10000 3 ab 10000 cde
2 abcde 2 20000 3 ab 20000 cde
3 abcde 3 00000 4 abc 00000 de
4 abcde 4 00000 5 abcd 00000 e
5 abcde 5 0000 6 abcde 0000 5
6 abcde 6 0000 6 abcde 0000 6
7 abcde 7 0000 6 abcde 0000 7
8 abcde 8
0000
6 abcde 0000 8
9 abcde 9
0000
6 abcde 0000 9
Because the sample UPC-E code ends in a
6 , the insertion digits 0000 are inserted at the sixth digit (insertion position 6):
1234500006
Add the N umber S ystem C haracter of 0 to the sample data:
01234500006
Use the UPC-A check digit calculation described in the previous section to produce a check digit as if it were a UPC-
A code. The check digit for the sample data is:
5
The complete 8 digit code consists of the Number System Character , the original 6 digit code and the check digit :
01234565