ISSN numbers are used to identify 'serial' publications such as newspapers, magazines and journals. An ISSN barcode can be used to contain the ISSN number - it is the standard barcode format for use on magazines in most countries. An ISSN barcode is actually similar to ISBN-13 and EAN-13. However, the way the ISSN number is encoded in the barcode is different. This section explains the features of the AVS Barcode Source software that are specific to ISSN barcodes.

Note that more detailed general information about ISSN numbers, how to get one, and barcodes containing them is available from the PPA website.

ISSN barcodes are based on the EAN-13 barcode standard, which is also support by AVS Barcode Source. The EAN-13 specific features of the product are described here.

ISSN barcodes use the main EAN-13 barcode to store the ISSN number, and a separate 'additional' barcode to store the daily/weekly/monthly issue number. The ISSN barcode image can also contain the ISSN number above the above the barcode, in simple text format.

The encoding of an ISSN number into a barcode is slightly different from other barcode formats, as explained now:

When you receive your ISSN number, you will normally receive an 8 digit number. The 8th digit is a 'check digit', which helps check that the first 7 digits are accurate.

To create a barcode based on your ISSN number, you need to enter the following into the 'ISSN number' box in the AVS Barcode Source screen:

• First, enter the 3 characters "977". All ISSN barcodes should begin with the number 977, which signifies that ISSN numbering is in use.
• Then, enter the FIRST SEVEN digits of your 8-digit ISSN number. Do not enter the 8th digit! Due to the way ISSN numbers are encoded into barcodes, the 8th digit is not used.
• Then enter your two digit code known as a 'sequence variant'. This usually starts at 00, but will increase by 1 every time the price of the publication changes.
• If you have left the 'add checksum' box ticked, then the checksum will be displayed for you just below the 'prefix' box. If you do not have the 'add checksum' box ticked, then either tick it now, or enter the checksum yourself as the last digit in the 'ISSN number' box.

The barcode should then be displayed for you in the preview window. Note that even though you only enter the first 7 digits of your ISSN number in the 'ISSN number' box (because only the first 7 digits must be in the barcode), the 8th digit is automatically calculated by the software and displayed as part of the ISSN number above the barcode.

You may now enter the issue number in the 'Additional Info' box. Typically, this would be 01-07 for daily publications, 01-53 for weekly ones, or 01-12 for monthly ones. When you have entered this additional information, a secondary 'add on' barcode will appear to the right of the main one.

When the barcode is complete, it can be saved as one of a number of graphics formats such as BMP or TIFF, or the EPS vector format which is used in many desktop publishing packages.

Note that the 'AVS Barcode Source' product supports a number of 1-dimensional (linear) barcode formats, not just ISSN. For a full list, see the main product details page.