...although I'm a little worried about the floating inputs on U12B, maybe he forgot to finish the diagram. They should at least have had tie resistors on those pins. With that sort of thing, it may not be viable to build it as the documentation is questionable.
Presumably this is the document:Aren't there circuits in the 'seminal' PET IEE488 book for these types of interfaces?
I'll look around but don't hold your breathWow, thanks, I didn't know the ADA1800 existed. It may well even be rarer than the ADA1450. It turns out it has been reverse engineered, I found the schematic on zimmers ( Attached). I could make that very easily.
Would you happen to know if the user manual is around for this one , DIP settings etc ?
I agree.>>> Yes, a classic bowtie flip-flop.
Just not drawn classically!
U5C and U5D are the 'listen' S/R flip-flop.