Re: Can only be partly right. Message #3 Posted by Eric Smith on 27 Jan 2011, 6:17 p.m., in response to message #2 by Frank Boehm (Germany)
Traditionally HP used the first four digits for the year and date of the start of production of a specific revision level of a product. They might make products with a particular code for a long time, not even just one "batch", if there were no design changes. Those first four digits were what you looked up in the service manual for "back-dating".
Calculators started out that way, but quickly became the highest-volume HP product, such that the standard HP serial numbering scheme was not practical. For calculators, they decided to change the code every week, even if no design change had been made.
There were occasional errors or anomalies in the serial numbering. The serial number of the calculator was not particularly intended to be interpreted by anyone other than HP.
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