DATEL D/A Converter DAC-V12B3D

I know this is a long-shot, but I'll ask.
I'm sitting on a quantity of these D/A Converters, and I can't remember what instrument they go into.
Does anybody have an idea of a Manufacturer whose instruments used them, or an instrument model number?
They're probably 20 years old, and I remember them being high dollar, but I can't for the life of me remember what they were purchased to repair.
They would have been purchased for repair of a Test & Measurement instrument, or maybe a recorder of some type.
ANY help on this would be appreciated.
Thanks

 

So far, I've contacted DATEL directly, they were amused. They had to go back to their 1974 Data Book to find the device, and said they haven't sold any of them since 1988, .... so they're at least 30 years old. DATEL apologized, because they only have a couple of guys in the office I contacted, who are older than these devices, and they don't have any records anymore of what companies purchased them back then. But if there's a dinosaur out there like me, who knows what manufacturer used them in their equipment, I'd sure like to know about it.
Thanks again.