Barcode encyclopedia : Symbology postnet

Postnet, 5-digit, 8-digit ZIP+4code, 11-digit Delivery Point Code

POSTNET (POSTail Numeric Encoding Technique) was developed by the United States Postal Service (USPS) to automate the sorting of mail.
POSTNET encodes 5,9 or 11 digit number to represent a five digit ZIP code (32 bars), a nine digit ZIP + 4 code (52 bars) or an eleven digit Delivery Point code (62 bars).
The eleven digit delivery code as developed from the nine-digit ZIP code and the last two digits of the street address.

POSTNET is unlike other bar codes because data is encoded in the height of the bars instead on if the widths of the bars and spaces.The code comprises two frame bars at the beginning and end.

POSTNET is a demandingbar code symbology because it has a size and placement requirement. It cannot be reduced or enlarged. Bar width, height, and spacing are fixed.

Guidelinesfor creation and use of POSTNET are set by the USPS.