The barcode on the inlay or box gives a clue to the intended production order. For example, 5012439011002 represents:
In the early days of TelecomSoft, the production numbers started at 01, but they started using higher numbers for different brands or publishing labels, e.g. 201+ for the Firebird Gold titles, 301+ for the Firebird Super Silver range and 501+ for Rainbird.
TelecomSoft used different company ID numbers, starting with 2439 for everything and eventually using 2439 for Rainbird, 7095 for Silverbird and 7096 for Firebird.
Sometimes, the same barcode is reused (by mistake). For example, Bubble Bobble on the Spectrum is the same barcode as Ricochet on the Amstrad CPC! Other times, it could be deliberate. For example, the Opus Discovery version of Elite (supplied on 3.5″ disk and sold exclusively in Boots the Chemists stores in the UK) was produced in very small numbers and so it wasn’t considered necessary to produce a new barcode and all the work that involved.
Thanks to Terry Burton, whose online barcode generator was used to create the barcode images found on this web site.
For anyone interested, TelecomSoft used the EAN13 standard for barcodes on all of their products.