Did you mean the 15 and the 20? I think the 15 is the oem version of the 20, and the 5 is the oem version of the 10. The 11/05 and/or 11/10 came in at least 3 different boxes and 5 or 6 different backplanes available.

On Sun, Jan 25, 2015 at 10:41 AM, B Degnan <billdeg at buzz1.com> wrote: > > > I scanned some info on the launch of the Digital PDP11. As the documents > show, there was a "rev 1" PDP11/10 that was used as a process control > system. You could buy the 11/20 version that had the front panel. > Otherwise they were very similar/same systems. The "rev 2" PDP11/10 is the > unit most people are more familiar with, the core system is interchangeable > with the 11/05. > > Most references I have seen on the WWW do not include the original > PDP11/10, anyone have one? > > http://vintagecomputer.org/browse_thread.cfm?id=593 > > Bill >