🚀 go-pugleaf

Uniscope protocol goes farther back than the U100/U200/U400.  There were 
variants back before then, like the U300, which was large enough to own
a rather nice sized desk (for those of you who ever saw an 1108, the U300
was used as a console (after they got rid of the typewriter!)).  The U300
was an elegant arrangement for the times (1960's), with screen control and
block mode transmission.  Of course it was slightly different than the later
Uniscopes (like it transmitted backwards from current cursor position to the
Start Of Entry (SOE)).  However, it was as rugged as a rock, and there are
still(!) U300s running today, core planes for video memory and all.

Uniscope protocol in general falls into a BSC line discipline, much akin to
the IBM BSC3270 in nature.  Indeed, there is a LOT of similarity to the two
block mode devices.  

Unisys documentation on Uniscope protocol was usually disguised in terms of
finding a title that said what it meant.  I've got U100/U200, and U400
protocol guides if you need a reference to order from (or if out of print,
a reference or two).  I may even have some old U300 stuff up in the attic
somewhere ;-)