Re: Barcode Symbology

[Rosemarie Mier <bha001@MAIL.CONNECT.MORE.NET>]

I had asked the list about barcode symbology (how can you tell the
differences just by looking at them) and had a lot of requests for a hit.
I posted one hit that referred to a web site.

Barbara Allen in Tucson, AZ emailed this perfect answer for librarians:


"3 of 9 means that every digit or character is represented by 3 wide lines
(bars or spaces) and 6 narrow lines (bars or spaces).  All wide lines are the
same width and all narrow lines are the same width.  This makes 3 of 9
barcodes easier for scanners to read and they are read more accurately more
often. (We've tested this.)

2 of 5 means that every digit is represented by 2 wide lines and 3 narrow
lines.  This is an older format and not usually used for numbers longer than
5 or 6 digits.

Codabar means 2 different things.  The pattern for codabar bars and spaces is
complex and allows up to 5 different line widths, unlike 3 of 9 which only
has 2 widths, wide and narrow.  However, codabar is also used to refer to
14-digit numbers commonly used in libraries.  The first digit for a book
barcode is 3, followed by a 4 digit location code, followed by 8 digits of
number, followed by a check digit.    You can get 14 digit codabar numbers
printed in 3 of 9 and that is what our district uses.

As to telling the difference, if you look at a codabar barcode and a 3 of 9
barcode both with the same number of digits printed the same size, the 3 of 9
barcode will look denser.  It will contain more lines.  However, it's a real
judgment call to tell the difference. I don't bet money on my judgement and
I've seen a lot of barcodes!

Now for the good news.  Most scanners can be set up to read 3 of 9, codabar,
and 2 of 5 barcodes, so you can have them intermixed in your library and our
district does have them intermixed.  (We don't have any 2 of 5 because we use
the 14 digit numbers and it's more suited to shorter numbers.)

Cheers!"

Barbara Allen

END OF QUOTE

In a message dated 05/02/2001 3:14:41 PM US Mountain Standard Time,
>>bha001@MAIL.CONNECT.MORE.NET writes:
>>
>>> What is the difference in barcode symbology?    Can someone explain how I
>>>  would know by looking at a barcode whether it is
>>>                  3 of 9,
>>>                  2 of 5, or
>>>                  14 digit codabar
>>>  symbology?  Why are there differences?
>>
>>
>>Barbara Allen
>>Program Analyst
>>Library Services
>>Site #5619
>>Tucson Unified School District
>>Tucson, AZ
>>bsallen@aol.com
>>

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