Printronix L7032 Programmer's Reference Manual page 176

Chapter 3
Bar Codes
Table 24. BC412 Character, Module Sequence, and Character Value
Check Code
The BC412 has a mod 35 check character. The check character is placed in
the second position behind the first data character. The check code is
automatically included in the bar structure; however, it is not included in the
PDF. The check digit computation is shown below.
Let D = D1D2....Dn be a string of n data characters and C = C1C2....Cn+1 be
a string value of n+1 encoded characters.
V1 = Character value of C1. Refer to Table 24.
Fo = (Sum of Odd V1) Mod 35
Fe = (Sum of Even V1) Mod 35
F = (Fo + 2Fe) Mod 35
Since the second character is the check character, designate the second
character of C1C2.... as the check character of D.
Set C2 = 0
therefore C1C3C4.... Cn+1 = D1D2D3....Dn.
Calculate Fo, Fe, and F
C2 = the character that has the check character value 17F Mod 35.
176
Module
Character
Sequence
T I---I--I-I--
U I---I--I--I-
V I---I---I-I-
W I----I-I-I--
X I----I-I--I-
Y I----I--I-I-
Z I-----I-I-I-
Start I--
Stop I-I
Character
Value
13
26
05
31
28
23
10