Operator's Guide E-15
PostNet Placement on a
Standard Business Envelope AB0-AB
CHECK DIGITS
The check digit is optional for Code 39, Interleaved 2 of 5, and Codabar; if
desired, the check digit should be supplied as part of the data according
to the specifications of the code you are using. EAN-8 barcodes do not
use check digits. The check digit for UPC-E and PostNet barcodes are
automatically calculated and appended by the printer. For UPC-A and
EAN-13 barcodes, a check digit is required, but it is not automatically
calculated and appended by the printer. The last character is used as the
check digit. See the table below.