Help me decode this serial number...



Here we go. Second HP in the collection. Its a HP16C, and I was trying to make sence of the serial number. Would somebody please tell me what this means (when it was made, etc)?

The serial is: USA 2228A11076



Refering to this calculator was produced 1982 in week 28 in the USA with part no. 11076 in the week.




The serial is: USA 2228A11076

Take the first two digits and at it to 1960 = 1982 (year).
The next two digits represent the week in the year = 28.
The letter indicates where it was made. A = America, B=Brazil, S=Singapore, etc.
The remaining digits tell you that it was the 11,076th 16C manufactured during that week in America.

Hope that helps!


The "week" number may not actually be the real week it was made. It is more like a production run number. Some of these "weeks" actually lasted many months. This was almost always the case for the earlier models like the '35, '80, '65, etc. Also the serial number for each "week" may or may not have started at 00001. Some seem to start at 10000, etc.

A lot of Singapore production starts with 80000 or 90000. And serial numbers seemed to be assigned sequentially across all models produced at a facility. They were not reset with each "week" or duplicated with another products number.


Thanks, David

After posting, I see that you seem to have answered my questions.



As I understand it, HP serial numbers are unique not only to a product line or facility, but across all HP products made anywhere in the world.

Although I haven't done it for a while, I regularly called HP during the 1980s and early 1990s for hardware support. The first question they asked was "What's the serial number of the equipment?" They didn't have to ask a second question; giving them just the serial number was enough to let them know exactly what the piece of equipment was: disk drive, printer, server, PC, calculator, protocol analyser, whatever. And it was not necessary to give them these serial numbers in advance as part of the support contract, so they weren't looking at our contract details in order to figure out what the equipment was.

So I've never assumed that the five digits after the letter indicated the number of calculators produced in a week. Still, I'd be interested if someone who actually worked in the allocation of these numbers at HP could clarify this.


I never worked for HP but I have seen a lot of their test equipment service manuals. In the service manuals the serial number is always used as a key to the revision level of the equipment. In some of the oldest manuals I have seen, the digits on the right side are used to define ranges of units that are at different revision levels even though the digits on the left are the same. But HP seems to have settled on changing the digits on the left whenever a significant change is made in production. As long as the digits on the left are the same, all the schematics, parts lists, and other drawings and procedures in the service manuals are applicable. This wouldn't prevent HP from internally keeping track of complete serial numbers vs. minor revisions, such as changing a vendor on a generic part.

As HP reprinted service manuals, they would update the main body of the manual for the then-current revision level and then add back-dating pages (at the back of the manual) listing all the changes made at each revision level. With this information you can always use a newer manual with older equipment.

I agree with David that the digits on the left don't necessarily reflect the actual year and week that a given unit was built. I imagine that they might reflect the actual year and week that a new revision level went into production.


I don't know how it works with the old style serial numbers, but the newer ones are definately not unique - in many cases, when you enter a serial number into the lookup tool it comes up with several different products with the same serial number. However, it is usually quite obvious which is the correct one - for instance, if a customer calls about a server and one of the product numbers starts with a D and the other starts with an F it is the one that starts with a D that is the correct one.

In case you're wondering how I know this, I used to work for HP until I had enough of the creeping Carlyfication...


Agreed, but wow! 11076 strikes me as a lot of calculators for one week's production. Particularly considering that the 16C is somewhat of a special purpose calculator.

I wonder whether some production lines were set up to run one model for a time, and then switched to producing a similar model as demand dictated? If so, would they have started the unit digits over at 00001 when they changed models or just continued with the next number?

For that matter, I'd probably have started each week's (or start of changed model) production with unit 00000; no sense in wasting a perfectly good number!

Or perhaps this is an example of when they neglected to change the week digits for a while?



... if you poke around a bit.


PS - I'm not trying to be rude, but I just thought that you would like to know that a lot of your questions seem to be answered on the site. I'm sure it is no bother for people to answer though...


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