What is it, and what date is it? DEC-11-HCRB-D, avilable online, is March, '72. DEC-11-HCRMA-C-D is June, '73. I see that EK-CR11-TM-004 is also available online: http://bitsavers.informatik.uni-stuttgart.de/www.computer.museum.uq.edu.au/… It's from July '75, and also mentions the M600. Bitsavers has the August '71 edition; if yours is later than that, it would be useful, _particularly_ if it has the M8291, which is the later card. Noel