M9047's are grant continuity cards (no circuitry, just PC boards with pins on the edge connector jumpered together to pass interrupt and DMA signals to the next slot.) A M9405 is a Q22-bus cable connector. This is what you use to hook multiple Q-bus chassis together into a multi-box system. On the other end of the cable you need a M9404. For information on connecting multiple Q-bus systems together, telling you which variants on the M9405 and M9404 cards you'll need for specific CPU/backplane combinations, see Micronote 29, "Q-bus Expansion Concepts", at http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/microno… You want the "Field Guide to Q-bus and Unibus Modules", at http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/hardwar… -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927