The International Standard Serial Number (ISSN) is an internationally accepted code which identifies the title of serial publications. It is an eight digit number consisting of seven digits plus a check digit which enables a computer to recognise when the number is incorrectly cited. The check digit may be an X, otherwise the ISSN is fully numeric.
The ISSN was developed by the International Standards Organisation (ISO) because of the need for a brief unique and unambiguous identification code for serial publications. A seven digit number was considered by ISO to be sufficient as the basis for numbering the entire population of serials.
ISSN numbers are issued by the ISSN Centre in the country in which the serial is published - see list of centres.
The ISSN International Centre (in Paris) maintains the worldwide Register of ISSN numbers and their associated titles.
An ISSN check digit may be calculated using the dLSoft ISSN Check digit calculator
When the barcoding system was set up for serials, it was realised that the ISSN as a unique identifying number for the title could be used as part of the barcode to identify the serial. The ISSN is therefore the title identifier in the barcode.
The ISSN coding scheme for barcodes is EAN-13, with the first three digits being 977, 7 digits showing the ISSN number of the periodical (without the ISSN check digit), and 2 spare digits (known as the "Sequence Variant" and used in the UK to indicate price code changes). The final digit is the EAN calculated check digit.
The ISSN number is reproduced above the barcode using the format of the initials ISSN, a single space, the first 4 digits, a hyphen, the last 4 characters.
Magazine barcodes are represented in EAN-13 format with a 2 digit add-on code representing, for example, the issue number.
ISSN barcodes with a 2 supplementary are supported by most dLSoft products. In some cases the supplementary characters must be separated from the ISSN numbers with a / character.
The ISSN identifies the title of a serial and stays the same from
issue to issue unless the title changes, at which a point a new ISSN
needs to be assigned.
The ISBN (International Standard Book Number) represents a single volume such as a novel, a monograph, a specific title within a monographic series or a specific issue of an annual or yearbook. ISBN numbers are generally issued by different agencies than ISSN numbers.
The two systems are complementary and can be used together on the same publication. On an annual, for example, the ISBN will identify a specific volume (e.g. 2007 edition, 2008 edition) whilst the ISSN identifies the title and stays the same each year.
ISBN should not be assigned to specific issues of periodicals and should not usually be assigned to any title published more frequently than once a year.
A fundamental difference between the two systems / numbers is that the stem of the ISBN identifies the publisher whereas the ISSN contains no publisher identifier. The ISSN is a purely arbitrary number that remains linked to the serial even when the responsibility for the serial passes from one publisher to another.