Well all of the above is basically true!
Starting in 1985, Swarovski commenced to use Alpha-Numeric numbering on a limited basis, on it’s commercial production
And from January 1991, the use became universal
Various forms have been used, with the two since August 1991 being A+9 (a letter followed by 9 numerals) and AA+7
All forms of A-N numbering incorporate three components:
- a letter that indicates the product line or product
- numerals that indicate the year of production (and mostly also the week of production), and
- numerals that indicate the production count (initially confined to the week of production, and later on an ongoing count)
1) General Patterns
a) Starting in 1985, various 8 digit forms of Alpha-Numeric numbering were used on some commercial production *
see the first table at:
https://www.birdforum.net/showthread.php?t=369004
b) In January 1991, A-N numbering was adopted on all commercial product lines in a standard 8 digit form of A+7
c) And from August 1991, the standard form was modified to 10 digits as A+9
The composition of the number is ‘Pyyww nnnnn’, where:
- P indicates the product line/ product
- yy the year of production, add 1930
- ww the week of the year, 01 to 52
- nnnnn the cumulative production count
(in contrast, the composition of A+7 was ‘Pyy wwnnn’, where the count was confined to the week of production)
2) Variations - 9 Digits
From August 1991, the 9 digit form of AA+7 has also been used on a limited basis
The composition is ‘PAyy nnnnn’, where the second letter effectively indicates ‘American’
The 2 uses are:
a) Where a telescopic sight can be manufactured with the reticle in either the first or second focal plane, the numbering indicates that the reticle is in the second plane
i.e. what’s commonly referred to as an American style reticle
b) Where SONA (Swarovski Optik North America) during servicing, replaces the part that had the original serial number
* The 9 digit form of A+8 was used briefly from around 1989, on 10x42 telescopic sights intended for law enforcement purchasers
The production presumedly had different warranty conditions, so the numbering clearly distinguished the units from regular commercial production
3) Modified A+9 Production Count
In October 2011, the 5 digit production count for A+9 numbering was modified (the 'nnnnn' component)
The first digit now identifies a product type, with the remaining 4 digits being the cumulative count
e.g. 1xxxx is used for Habicht Porro prism binoculars, and 4xxxx is used for the main lines of roof prism binoculars
So the count for the Habicht would go from 10000 to 19999 (a 10,000 unit range), and then reset to 10000
The advantage is that with the increasing number of models offered, models from different product lines can have the same alphabetic prefix
but be readily distinguished by the different number blocks
e.g. both the centre focus Habichts and the new NL roof prism line have an A prefix
For those interested in more detail, all of the above is expanded on in the six tables attached to the above link
- - - -
An SLC 10x50 with a serial number of ‘DA87 1810-’ indicates that the original numbered part was replaced by SONA when the unit was serviced it in 2017 (87 + 1930)
And by my observation of serial numbering, SLC 10x50 production was from mid 1997 to late 2010
John