The joke's actually on you: DQ11_RevL_Engineering_Drawings_Aug75.pdf 2021-08-09 14:05 ^^^^^^^^^^^^^^^^ I'd actually looked in http://bitsavers.org/pdf/dec/unibus earlier that morning (before I sent my request), and by chance I still had that browser window open. I suppose I could have done a screen-shot... That was mostly a joke. I mean, there are no DM11-AA documents of any kind online, so it would be interesting to get some (there are still a few un-answered questions); but there's a good DM11 entry in "pdp11 peripherals and interfacing handbook", 1972 edition, that enabled me to produce a decent entry: https://gunkies.org/wiki/DM11_asynchronous_serial_line_interface which is probably more than good enough - the interface is actually a dog, I doubt any still exist. Noel