Barcode FAQ v2.0

[Jerry Whiting]

Barcode FAQ ver 2.0 12.12.96
copyright 1995, 1996 Azalea Software, Inc.
in...@azalea.com www.azalea.com


>>> Introduction
>>> Printing Bar Codes
>>> UPC, EAN, JAN, Bookland, ISSN
>>> Code 39
>>> POSTNET
>>> Interleaved 2 of 5
>>> Code 128
>>> Codabar & MSI-Plessey
>>> The New 2D Symbologies
>>> OCR Fonts
>>> Specifications
>>> Credits


>>> Introduction

[A version of this FAQ with graphics is available at: http://www.azalea.com]

I've read many a note on the Net asking about bar codes. I love to hack bar
codes. In fact, I've been writing bar code software for over six years
with no end in sight. This modest FAQ is a chance to share a bit of my
experience while answering some of the re-occurring questions I see posted.

While it will undoubtedly make its way to other places, I will post this FAQ
periodically to various places online including USENET conferences, CompuServe,
and AOL. You can also retrieve it from our Web site: www.azalea.com

Bar codes are alternating patterns of light and dark that encode
specific chunks of information. When scanned, bar code symbols can be
converted back into the original string of text. Most bar codes consist of
patterns of rectangles but some of the newer symbologies use other shapes.

Bar codes are part of the automatic ID industry and are sometimes
referred to as "keyless data entry" because they can be used to encode and
decode information automatically. Bar codes can be scanned with little or no
error under less than ideal conditions. In some situations they can even be
scanned automatically without human intervention. Beats typing.

This FAQ will focus on creating and printing bar codes rather than the physics
of scanners. The scanners which read bar codes emit a red laser of a specific
frequency that works by distinguishing the edges within a symbol allowing
them to be scanned omnidirectionally. "I'm sensing my own light reflected
back at me. Now there's none. Ah, there's some more. No reflection., etc."

There are two types of scanners: portable readers and those that hook up
directly to your computer. If you have to go to the bar code, you need a
portable reader; if the bar code can come to you, consider a scanner that
attaches to your PC. Portable readers hold data in a buffer that can be
downloaded into your computer via a cable. Walk around the warehouse scanning
items as you do inventory. Go back to your desk and download the collected
data into your database. The non-portable readers plug into your keyboard
port and the keyboard plugs into them. With the reader between your keyboard
and the computer, the computer assumes you're typing really fast, without any
errors.

The firmware in most scanners can decode more than one type of bar code. Each
symbology (type of bar code) has a unique start bar and stop bar at the
beginning and end of the symbol, or some other unique pattern that allows the
scanner to autodiscriminate between symbologies without human intervention on
the fly. Some scanners can scan a pre-printed bar code that will then turn on
or off additional capabilities.

In general, each symbology tends to be used by a different industry or within
a different vertical market. In many ways, your decision as to which
symbology to use is dictated by what is being bar coded and where it will be
used. Or if you need to encode alphabetic data, some symbologies like UPC or
Codabar are out because they only encode numeric data. Your suppliers or
customers may have established conventions or standards that determine the
nature and structure of the symbols you can use. Bar codes may be part of a
larger labeling format that dictates what you have to adhere to. These are
issues that need to be determined _before_ you commit to a plan.

Most bar code symbologies employ one or more check digits within them to
ensure accuracy and data integrity when scanned. Others like Interleaved
2 of 5 employ other internal methods to guard against misreads. Human-
readable characters printed along with the bar code may be required or optional.


>>> Printing Bar Codes

Bar codes can be printed one of two ways: either from within a dedicated
bar code labeling programming (often using a thermal transfer printer), or
from within your favorite application using bar code fonts or graphic
elements. The former is where the auto ID industry is coming from
historically. The latter is more flexible and can be integrated into your
existing work process.


>>> UPC, EAN, JAN, Bookland, ISSN

UPC, EAN, JAN, Bookland, and ISSN bar codes are all related. (Purists will
insist that all are a subset of EAN.) These are the symbols used on items
destined to be scanned at the checkout line in retail settings. All are
fixed length symbols that consist of numbers only. The UPC symbols used in
the U.S. are a subset of EAN. JAN are equivalent to EAN. Bookland is an EAN-
13 with a 978 country code and a 5-digit supplemental code. ISSN is an EAN-
13 with a 977 country code and a 2-digit supplemental code.

UPC (Uniform Product Code) bar codes are the symbols that get scanned at
the checkout line at the grocery store. Contrary to popular belief, they
do not include the price of the item. There are four parts to a UPC
symbol:
- the number system, a single digit in the lower left corner
- a 5-digit manufacturer number assigned by the Uniform Code Council in
the left hand notch
- a 5-digit product number assigned by the manufacturer that uniquely
identifies each product in the right hand notch
- a check digit found in the lower right corner.

When a bar of soap gets scanned, the numbers in the UPC symbol are a
pointer into the inventory database in the back room of the store. This is
how the cash register display and the printed receipt know what item you
bought and how much it costs. Price changes involve changing the central
database. (Otherwise a price change would require a new bar code on each
affected item.)

UPC symbols are numeric-only, are of a fixed length, mandatory in the
retail channel, and not used anywhere else (for the most part). There are
two flavors of UPC symbols: UPC version A and UPC version E. The former
is the full length symbol and the latter is a narrower, zero-suppressed
version. Version E symbols are used where space is at a premium (such as on
a small package label).

An optional 2- or 5-digit supplemental code is sometimes used with UPC
symbols. Supplemental codes appear to the right of the main symbol and have
the human-readable digits above the bars. For instance, a 2-digit
supplemental code is used for the issue date on a magazine cover.

EAN (European Article Number) and JAN (Japanese Article Number) symbols
are used on retail items in Europe, Japan, and other non-U.S. parts of the
world. There are two flavors of EAN/JAN symbols: EAN-8/JAN-8 and EAN-
13/JAN-13. EAN symbols include a two-digit country code which reflects
the origin of a product.

Bookland bar codes are based on ISBN numbers and are used on book
covers. They are sometimes referred to as ISBN bar codes, however this is an
inaccurate description. Bookland symbols are EAN-13 bar codes, with a 978
country code and a five-digit supplemental code based on the book's retail
price. The supplemental code begins with "5" in the U.S., "6" in Canada, etc.
The price is represented by the second through fifth digits. If the retail
price is less than four digits, it's padded with leading 0's. Therefore a
book that costs $4.99 would have a supplemental code of 50499 in the U.S. and
60499 in Canada.

ISSN bar codes are based on the ISSN number and are used on periodicals
outside of the U.S.. These are EAN-13 bar codes, with a 977 country code, and
include a 2-digit supplemental code which represents the issue date (01 for
January, 02 for February, etc.).

The human-readable characaters found under UPC, EAN, JAN, Bookland, and ISSN
symbols are created using the OCR-B font. The ISBN number itself is usually
created in OCR-A.

The newest thing is a coupon format that combines UPC/EAN symbols with a
Code 128 symbol to the right of it. It is sometimes mistaken for the standard
UPC/EAN supplemental code.


>>> Code 39

Code 39 (a.k.a. Code 3 of 9) is by far the most popular bar code
symbology used for ID, inventory, and tracking purposes. For instance,
when you rent a videotape, it's usually a Code 39 symbol that gets scanned at
the check out counter.

Code 39 has several advantages:
- it can be read by all popular scanners
- its standard character set includes both uppercase letters and numbers
- the string the symbol represents can be of variable length
- a check digit is rarely used (but available if you need it)
- it can be printed in a wide variety of sizes and dimensions.

The Code 39 character set is: A-Z (uppercase), 0-9, $, %, +, -, ., /,
the space character, and the asterisk (reserved for the start and stop
bars). The full 128 lower ASCII characters can be represented by
combining two characters. For instance "a" is represented by "+A".
There is an optional check digit that can be used with Code 39 where
data integrity is imperative. (The health industry is one of the few
places where the Code 39 check digit is used.)

The exact dimensions and aspect ratio of a Code 39 symbol's element can
vary depending on space requirements, the printing method used, and the
size of the desired symbol. The only requirement for converting a string
into a Code 39 symbol is to add an asterisk (*) at the beginning and the end
of the string as the start and stop bar. So to encode "FREEJAZZ" you
would format "*FREEJAZZ*" in Code 39 and it would yield "FREEJAZZ" when
scanned.

Each character has a total of nine elements (bars and spaces) called
modules, of which 3 of the 9 are wide (hence the name Code 3 of 9). The
wide element to narrow element ratio can be between 2:1 and 3:1. Some
industry-specific specifications demand a 2.2:1 ratio for smaller symbols.

Code 39 symbols can be recognized by their distinctive start and stop
bars, represented by an asterisk (*). The pattern of the asterisk is
narrow bar, wide space, narrow bar, narrow space, wide bar, narrow
space, wide bar, narrow space, narrow bar.

|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|
|X| |X| |XXX| |XXX| |X|

[Note that the above sample illustration must be viewed in a monospaced
font like Courier in order to make any sense. This is simply a limitation
of using only ASCII text to do graphic images. The version of this FAQ on
Azalea's home page includes graphics.]


>>> POSTNET

POSTNET bar codes are the bar code symbols used to encode ZIP codes on
U.S. mail. The Postal Service mail handling process is designed to be
fully automated and POSTNET bar codes are the glyphs that feed the
automated equipment. Properly addressed pre-bar coded mail is the key to
routing mail. Ideally every mail piece that enters the flow should be bar
coded.

POSTNET symbols are different from other symbologies because the
individual bar height alternates rather than the bar width. Each
number is represented by a pattern of five bars. A single tall bar is
used for the start and stop bars.

|| | | | || || || | | |
||||||||||||||||||||||||||||||||

[Note that the above sample illustration must be viewed in a monospaced
font like Courier in order to make any sense. This is simply a limitation
of using only ASCII text to do graphic images. The version of this FAQ on
Azalea's home page includes graphics.]

Each symbol includes a check digit defined as the single digit that must
be added to the sum of all the digits to make the total the next
multiple of 10. For example, 98116's check digit is 5 because:
9+8+1+1+6=25 and 25 + 5 = 30.

POSTNET can be used for 5-digit, 9-digit ZIP+4, and the new 11-digit
Delivery Point Barcode. They are often used in conjunction with one of
the three FIM bars (Facing Identification Marks) which are found on the
upper right corner of a mail piece like Business Reply Mail.


>>> Interleaved 2 of 5

Interleaved 2 of 5 is one of the most popular symbologies used by the
shipping and warehouse industries. It is also used in the medical field.
Interleaved 2 of 5 is unique because the widths of both the spaces and of
the bars vary. The bars and spaces are interleaved: the odd-numbered digits
are represented by the bars and the even-number ones by the spaces. One
strong advantage of Interleaved 2 of 5 is that it is very compact given,
that the spaces encode information too.

To find a sample of Interleaved 2 of 5, check out the corrugated boxes
in which things are shipped to the grocery store. The bar codes are often
located within bearer bars, creating a 1/4" frame around the bar code itself.


>>> Code 128

Code 128 is a symbology used in the shipping industry and on labels.
Code 128 is becoming more and more popular, especially in Europe. There are
four different versions of Code 128: code set A, code set B, code set C, and
UCC/EAN-128. Code 128 is very, very compact and results in a denser symbol
than Code 39.

Code set A - includes 0-9, A-Z upper case, and the ASCII control characters.
Code set B - includes 0-9 and A-Z, both upper case and lower case.
Code set C - encodes pairs of numbers, 00-99, yielding dense symbols.
UCC/EAN-128 - symbols have a specific format and are used for shipping
container codes.

One way to recognize a Code 128 symbol is by looking for its distinctive stop
bar. The pattern of the stop bar is bar2, space3, bar3, space1, bar1, space1,
bar2.


|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|
|XX| |XXX| |X| |XX|

[Note that the above sample illustration must be viewed in a monospaced
font like Courier in order to make any sense. This is simply a limitation
of using only ASCII text to do graphic images. The version of this FAQ on
Azalea's home page includes graphics.]


>>> Code 93

Code 93 is a compact alphanumeric symbology that is a complement to Code
39. The two can be mixed within an environment. Scanners are able to
autodiscriminate without human intervention. Because of its small size it
is used on small electronic components. Code 93 is not a very popular
bar code symbology.


>>> Codabar & MSI-Plessey

Codabar is a numeric symbology used by FedEx, in libraries and blood banks.
One distinct feature of Codabar is that it has four different start and stop
bars, the selection of which you use can encode information as well as the
decoded string.

MSI-Plessey is another numeric symbology used in libraries.


>>> The New 2D Symbologies

There is a new generation of extremely high-density, non-linear symbologies
that are called 2D (two dimensional) symbologies. Some look like multiple
lines of bar codes stacked on top of each other, and others resemble a
honeycomb-like matrix. While symbologies such as Code 16K, PDF417, Data
Matrix, and Code 1 are being advocated by various groups, the jury is still
out as to which of these new symbologies will win wide acceptance.

Now that PDF417's specification has been officially put into the public
domain, it appears that it will be the winner or at least the contender that
smart money bets on.

One thing that PDF417 advocates point out is that because this symbology
encodes up to 1108 bytes of information, it really is a portable
data file (PDF), as opposed to being a record index or that points back
into an external database. Using PDF417, one can put a summary of your
driving record on the back of your drivers license or a photo of you in JPEG
format as the Pentagon is doing.


>>> OCR Fonts

Three related symbologies bear mentioning. Three OCR (Optical Character
Recognition) fonts are in widespread use.

OCR-A is used on book covers to format the ISBN number itself. OCR-B is used
for the human readable digits under UPC, EAN, JAN, Bookland, and ISSN bar
codes. It's also used for the optional human-readable digits used with Code
39 and Interleaved 2 of 5 symbols.

MICR (Magnetic Ink Character Recognition) is the font used for the
numbers in the lower left corner of your checks. When printed with a
special magnetic ink or toner, they can be scanned by the bank's check
processing machines.



>>> Specifications

To get a manufacturer number assigned to you or for more information
about UPC symbols, contact:
Uniform Code Council, Inc.
8163 Old Yankee Rd. Ste J
Dayton OH 45458
937 435.3870
937 435.4749 FAX

For information on EAN symbols, contact:
International Article Numbering Association (EAN)
Rue Royale 29
B-1000 Bruxelles
Belgium
011 32 22 18 76 74
011 32 22 18 75 85 FAX

Article Numbering Association (ANA)
11 Kingsway
London WC2B 6AR
England
44 171 836 3398
44 171 240 8149 FAX

For information on JAN symbols, contact:
Japanese Standards Association
1-24, Akasaka 4, Minato-ku
Tokyo 107 Japan

To get an ISBN number for a book assigned to you, contact:
ISBN Agency
121 Chanlon Rd
New Providence NJ 07974
908 665.6770

Book Industry Study Group, Inc.
160 Fifth Ave.
New York, NY 10010
212 929.1393
212 989.7542 FAX

To get an ISSN number for a periodical assigned to you, contact:
National Serials Data Program
Library of Congress
Washington, D.C. 20540
202 707-6452

ISSN Canada
National Library of Canada
395 Wellington Street
Ottawa, ON
K1A 0N4
Canada

Canadian Serials Industry Systems Advisory Committee
1 Blue Springs Drive
Waterloo ON
N2J 4M1
Canada

Periodicals Barcoding Assoc.
Periodical Publishers Assoc.
Imperial House
15-19 Kingsway
London WC2B 6UN
ENGLAND
44 171 379 6268
44 171 379 5661 FAX

Publishers outside the U.S. should contact their country's national
library for information about ISSN.


For specifications on other bar codes, contact:
Automatic Identification Manufacturers (AIM USA)
634 Alpha Dr.
Pittsburgh PA 15238-2802
412 963.8588
800 338.0206
412 963.8753 FAX
a...@aimusa.org
412 963.9047 BBS

America National Standards Institute (ANSI)
1430 Broadway
New York NY 10018
212 642.4900
212 764.3274 FAX
http://www.ansi.org

International Organization for Standardization (ISO)
1, rue de Varembe
Case postale 56
CH-1211 Geneve 20
Switzerland
41 22 749 01 11
41 22 733 34 30 FAX
cen...@isocs.is.ch
http://www.iso.ch

>>> Credits

Let's get one thing straight: I own Azalea Software, Inc., a bar code
software company. To learn more about Azalea's bar code fonts for Windows,
the Macintosh, and other platforms please send email to: aza...@azalea.com or
visit our web site at: http://www.azalea.com

Azalea Software's bar code fonts are available in TrueType and Type 1 format.
Install them like any other font and they'll appear in the font menu of all
of your favorite applications. Then you can print from within any word
processor, database, spreadsheet, or your own custom application. We even have
sample code we can share with you to get you started. Printing high quality
bar codes was never this easy or this much fun!

WE LOVE TO HACK BAR CODES!


Jerry Whiting
Azalea Software, Inc.
PO Box 16745 Seattle WA 98116-0745

1.206.932.6028 1.206.937.5919 FAX

www.azalea.com aza...@azalea.com