I’m sure this will be answered quickly, it’s probably fairly well known. I have no idea what to call it, but I think it’s coding of some sort. In the bottom right-hand corner of some papers that my new employer sent me, there is a little box maybe 1/4 in square, with lots of little black dots arranged like a really complex barcode. I supect this is either coding for the actual text of the letters, or is a reference for the copier. I’d have googled this, but like I said, I have no idea what it’s called.
You are pretty much right. Does it look like one of these? If it is what I’m thinking of, it’s a Data Matrix two-dimensional bar code.
As to what could be stored in it, I have no idea. Looks like many of the links on that page are outdated, but probably nothing some basic Googling won’t turn up.
Yep, it’s a Data Matrix. I don’t know what’s in it either. It’s from Merck, so it’s probably some silly form letter reference.
I did a little work on the PDF (not the same as Adobe pdf document) 2D symbology; it is really interesting in that it can be encoded with differing levels of redundancy; at the highest level of redundancy, a large portion (any two thirds IIRC) of the barcode can be torn off or otherwise obscured/obliterated and it can still be readable.