ISSN (International Standard Serial Number) is used for serial publications, i.e. magazine and periodicals. The guidelines for the EAN implementation of the ISSN are published by the Periodicals Barcoding Association (P.B.A.)
The ISSN/EAN symbol was originally intended for the U.K but is being taken up by other countries around the world who use EAN as the standard retail bar code.
Each individual title (magazine, newspaper, periodical or journal) is allocated an ISSN by the UK National Serials Data Centre administered by the British Library.
The ISSN number consists of two blocks of four numbers separated by a hyphen. There is no other reason for this structure than to make the number easy to read.
The last digit of the ISSN is a check digit. The calculation used to find the ISSN check digit is exactly the same as that for ISBN.
The previous diagram shows the ISSN/EAN bar code with the 2 digit add-on code for issue number.
The component parts are as follows:
1. The ISSN number - printed above the bar code in the font OCR-A
2. ISSN prefix - The prefix 977 is reserved within the EAN numbering system to signify an ISSN code.
3. The ISSN number minus the check digit - Only the first seven digits of the ISSN number appear in the bar code. The ISSN check digit is not represented.
4. Sequence variant - A two digit space is used to hold the number of times the issue price has changed since the bar code was first used on the publication.*
5. The EAN check digit - This number is calculated from the entire EAN number - 977+ISSN(without ISSN check digit)+Sequence variant.
6. Two digit add-on - This supplementary code is used to differentiate between the various issue numbers. There are no rigid rules, but generally weekly publications will be numbered 01 - 52 (or 53) through the calendar year, daily publications will run from 01 to 07 repeating weekly and monthly publications will be numbered from 01 to 12.
* The sequence variant is used to signify a change of price. It can be used to signify a permanent change or a "special" issue at a different price from the regular one. This guards against price confusion at the checkout.
The ISSN symbol may appear with or without the two digit add-on.
Bar Code Uses
Bar Code Structures
Getting a Good Scan
PostScript Imaging of Bar Codes
ITF (Interleaved 2 of 5 )
Glossary of Bar Code Terms