USPS bar codes

 Article 4473 of comp.misc:

From: balcer@gypsy.siemens-rtl (Marc J Balcer)

Subject: Re: U.S. Postal Service Zip+4 bar code:  what is it?

Summary: Summary of Responses and Other Information

Message-ID: <3767@siemens.UUCP>

Date: 16 Nov 88 18:47:18 GMT

Organization: Siemens RTL, Princeton NJ

Thanks for all the replies to my question about USPS bar codes.  

Here's a summary, as well as other information I researched myself.

The code itself is a 2-of-5 code, with leading and trailing "1" bars

and a checksum digit.

The five binary digits represent 7, 4, 2, 1, 0.

Each decimal digit in the zip code is represented by the following pattern:

    0 = ||...     5 = .|.|.

    1 = ...||     6 = .||..     . represents a short bar

    2 = ..|.|     7 = |...|     | represents a long bar

    3 = ..||.     8 = |..|.

    4 = .|..|     9 = |.|..

Either a 5-digit or 9-digit (Zip+4) code may be encoded using this

method.  The actual bar code contains either 6 or 10 digits.  The

last digit is selected such that the sum of all of the digits

(including the last one) is a multiple of 10.

For example, the zip code for Siemens is 08540:

    1. The check digit is 3.  (0 + 8 + 5 + 4 + 0 + 3 = 20)

    2. The bar code is

|||...|..|..|.|..|..|||.....||.|

        |0----8----5----4----0----3----|

According to the USPS Domestic Mail Manual (Section 917.528), the bar

code is placed at the bottom of the envelope so that the first bar is

between 3.875 and 4 inches from the right edge of the envelope.  The

baseline of the bar code must be 0.25 inches from the bottom of the

envelope.

A "1" bar must be 0.125 inch (plus or minus .010 inch) high.

A "0" bar must be 0.050 inch (plus or minus .010 inch) high.

All bars must be 0.020 inch (plus or minus .005 inch) wide.

Bars should have a nominal horizontal spacing of 21 to the inch, 

plus or minus one bar.

The USPS does give bulk-rate discounts for presorted and bar-coded mail.  

The best discounts are for Zip+4 presorted and bar-coded.  

Check with your local postmaster before sending your own bar-coded

mail.

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Marc J. Balcer

[balcer@gypsy.siemens.com]

Siemens Research Center, 755 College Road East, Princeton, NJ 08540

(609) 734-6531

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