Never Mind: MicroVAX 3

You certainly can! On both the TQK50 and TQK70, the CSR is set by jumpers, not by DIPswitches. (the DIPswitches on a TK50 actually set the rev level reported by TMSCP inquiry commands, which changed more often than the CSR's at one point!) The default CSR is 774500. The CSR must be a multiple of 4, so the low two bits are always zero, and the CSR must be in the I/O page, so the high 5 bits are always on. The in-between bits are set with the jumpers near the edge connectors. Seen with the edge connectors to the bottom, the default looks like: XXXXXX (jumper in for CSR's starting with 77, jumper out for 76) XXXXXX \ | . . |- a "4" | . . / XXXXXX \ | . . |- a "5" | XXXXXX / . . \ | . . |- a "0" | . . / . . jumper in if last digit is "4", out if a "0". The "autoconfigure" CSR selection for a second TK50 in a system is 760404, though of course this moves around if you've got other second controllers in the systems, or a serial multiplexer, and of course RT-11 doesn't care a damn bit about autoconfigure rules as you've got to manually configure it anyway :-) -- 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