Data - Coding systems

Bar coding - Check characters

1. Designate the rightmost character odd.
2. Sum all of the characters in the odd positions and multiply the result by three.
3. Sum all of the characters in the even positions
4. Add the odd and even totals from steps two and three.
5. Determine the smallest number that when added to the result from step four, will result in a multiple of 10. This is the check character.

Number system character =  0
Message characters =	    0123456789
Position =	           OEOEOEOEOEO
Sum of odd positions =	   0 + 1 + 3 + 5 + 7 + 9 = 25
Odd positions X 3 =	   25 x 3 = 75
Sum of even positions =	   0 + 2 + 4 + 6 + 8 = 20
Sum of even and odd =	   75 + 20 = 95
Check character =	   5
Tag to be encoded =	   001234567895

Flag characters =	20
Message characters =	  0123456789
Position =	        EOEOEOEOEOEO
Sum of odd positions =	0 + 1 + 3 + 5 + 7 + 9 = 25
Odd positions X 3 =	25 x 3 = 75
Sum of even positions =	2 + 0 + 2 + 4 + 6 + 8 = 22
Sum of even and odd =	75 + 22 = 97
Check character =	3
Tag to be encoded =	2001234567893

Flag characters =	20
Message characters =	  12345
Position =	        OEOEOEO
Sum of odd positions =	2 + 1 + 3 + 5 = 11
Odd positions x 3 =	11  \(mu  3 = 33
Sum of even positions =	0 + 2 + 4 = 6
Sum of even and odd =	33 + 6 = 39
Check character =	1
Tag to be encoded =	20123451