Dell date codes
Based on a wiki update posted by Zilog Jones, Dell keyboard serial numbers are reported to take the following form:
CC is the country code (CN for China, KR for Korea etc). PPPPPP is the Dell part number. Y is the final digit of the year; the decade is not recorded, as this digit wraps every ten years. M is the base 36 hexadecimal month number, and D is the base-36 day number.
The most useful example cited by Zilog Jones (as it shows the use of base-36) was this one:
Zilog Jones reports this as being 13th of September 2005, and this is a close match for the date codes printed on the controller PCB.
From some currently otherwise unpublished photographs of a Primax Electronics Ltd KB4021 (Dell KB212-B):
“3AI” would be the 18th of October 2013. Here, you can see that the year digit has wrapped around. The serial number date is a match not only for the PCB (week 35 of 2013 occurred in August) but also the date of manufacture presented on the label itself.
My Logitech-made Dell KB522 multimedia keyboard is another match: the box label reports a manufacture date September 2012, the case is marked “12” internally via a wheel, and the serial number is “CN-02H8RN-75131-294-00VW”.