Sure, glad to help. I'm at just about this stage with my 11/23's, so it's no biggie. so addresses I can do that. Here you go (in Unix assembler, which is somewhat different from the DEC one in some syntax details, notably '/' for comment, not ';'): br4 = 200 stack = 2000 conregs = 177560 rcsr = 0 rbuf = 2 tcsr = 4 tbuf = 6 rint = 100 . = 60^. conr; br4 / 1020 200 . = 1000^. test: mov $stack, sp / 12706 2000 mov $conregs, r1 / 12701 177560 / mov $rint, rcsr(r1) / 12761 100 0 mov $rint, (r1) / 12711 100 1: wait / 1 br 1b / 776 conr: movb rbuf(r1), tbuf(r1) / 116161 2 6 rti / 2 (The numbers on the right are hand-assembled octal, but I did put it through the assembler to make sure I'd gotten it right. The commented out instruction is clearer, but adds one word to the required type-in.) Here it is in address/location form: 60 1020 62 200 1000 12706 1002 2000 1004 12701 1006 177560 1010 12711 1012 100 1014 1 1016 776 1020 116161 1022 2 1024 6 1026 2 Start with "1000G" to ODT. It should echo everything you type, using interrupts from the console DL11 to do so. I did try this on my machine to debug it, and fixed one minor thinko (I had used "rts pc" instead of "rti"). After that, worked like it says on the tin. My machine is (at the moment) basically identical config to yours: an 11/23, a memory card (NatSemi), and a DLV11-J. (No terminator/ROM, it's in a Sigma box which has termination built in.) OK. 23+, Yes, that was my sense too. Do you have a memory test, yet? I am planning on whipping up one of those too, for my own use, although it will be more elaborate than that console interrupt test. If you can use octal dumps to load, I can produce that form pretty easily: let me know what syntax your loader takes. so Interesting; I have a whole stack, and the first one I tried seemed not to work. Noel