Some original equipment manufacturers do not clearly identify the S/N on their instruments. For instance, I am looking at a brand new Extech 380560 milliohm meter that has "R.110219" on a label which is probably the S/N but is not identified as such.
I just got off the phone with Extech customer support and they said the "R.110219" is from the factory where the instrument was made and is not the S/N they use. He said they use the number under the barcode as the "US" S/N.
There are a large number of Extech instruments like this.
I am interested to know what the PMEL community is using as the S/N of record on these instruments?
I believe the first problem that must be solved based on your example is to get people to stop buying extech.....
Yeah, I don't love extech products either but we see a lot of them.
Extech's moto:
"Our equipment does lots of stuff, but not very well.".
They are not the only ones to do this. Both B&K Precision and R&S do the same.
If it works, it must be a Fluke!
I've seen a lot of French made instruments (current clamp probes from a major manufacturer for instance) that have no S/N at all. Perhaps that was just a fluke.... All kidding aside, I do love Fluke stuff.