The ISSN is defined by the ISO 3297 standard

The ISSN is defined by a specific standard, i.e. it is the object of a definition and of standardized application rules internationally adopted in the framework of ISO (International Organization for Standardization) which groups the official standardization institutions throughout the world. This has allowed from the origin the ISSN to be a tool internationally used in the most diverse frameworks in a coherent and compatible way. The ISSN International Centre is the registration institution officially designated by ISO for the ISSN.

The other identification codes

The principle of an international standardized identification code exists in other domains. Thus monographs (books) are identified through the ISBN (International Standard Book Number), musical scores by the ISMN (International Standard Music Number), sound recordings by the ISRC (International Standard Recording Code),etc.

To each of these codes corresponds a particular and well defined field of application and a logic which is proper to it. It should also be noted that as the ISSN can among others be applied to series of books, a book belonging to a particular series will have both an ISSN (identifying the series) and an ISBN (identifying the given monograph as such).

The ISSN and the SICI code (Serial Item and Contribution Identifier)

The ISSN is the core element of an identifier which is of capital importance for the identification of serial issues and articles : the SICI.

The SICI code (Serial Item and Contribution Identifier), is described in the American standard ANSI/NISO Z39.56. The SICI code is more and more widespread among the great international scientific publishers, reproduction rights agencies, etc. The SICI even provides for the unambiguous identification of each article (or contribution) published in a given issue of a serial publication.

The SICI, located under the barcode, contains :
1. the ISSN
2. the date of publication, between brackets and formatted according to the formula AAAAMM (199303 means march 1993).
3. the issue number (here 52)
4. the version number of the standard, here 1, preceded by a semicolon.
5. and lastly a hyphen which precedes the control character calculated on the basis of all the preceding characters.

The machine scannable bar code representation of the SICI at the issue level is known as the SISAC Bar Code Symbol. Throughout the serials industry, major publishers are now printing the SISAC Bar Code Symbol on the covers of their publications and library systems vendors are developing interfaces for automated check-in systems.

The SISAC barcode symbol contains all the elements of the SICI but formats them in a somewhat different manner in order to obtain an entirely numeric code, which allows a reduction of the length of the resulting barcode in the 128 symbology.

SISAC is an acronym which stands for Serials Industry Systems Advisory Committee, an organization which was created in the United States in 1982 to develop standardized exchange formats to facilitate the handling of serial publications (in particular in transactions between libraries, subscription agencies and publishers).