On 07/05/2012 05:48 PM, Boyanich, Alastair wrote: Thanks, Yeah I was more than a bit hot for it also. Looks like it came out of Ford Aerospace and Comms Corp (P.S. FAAC Best acronym next to our old one of FACOM which was changed when someone heard a .jp accent saying "FAKKUM" to one of the clients *G*). No clue how it ended up in Adelaide unless they were doing defence contracting. Yeah really! But, a great score either way. You CAN, however, get a CIS option (if you can find it!) for your 11/23! I too would love to mess with CIS a bit; I've never done so. I have two CIS option board sets for my 11/44s but have not yet installed them. Nice! (tm) .. got a photo's of the 11/44 option? Not yet, but keep after me about it and I will photograph the boards. Really wondering about the /23Plus. If the option for it is just PROM's that should be pretty easy to reproduce. It won't be at all easy to reproduce. They are MICROMs. The F11 CIS option is one of those multi-chip carriers, but for CIS it is two 40-pin-DIPs wide, and contains six MICROM chips. These are bipolar mask-programmed ROMs with an (I think?) undocumented interface. I would be more than a little surprised if anyway, even someone of technical means, could reproduce that. Since you have an 11/23+, you are in luck; that has one more 40-pin socket than the dual-width 11/23 CPU board. It can accommodate both the CIS MICROM option and the floating point MICROM option. On the dual-width 11/23 boards, you have to remove the floating point MICROM. You could remove the MMU chip to make room for the double-wide CIS chip carrier, but that'd be pointless because, if memory serves, the floating point registers reside within the MMU chip. The 11/24 has yet one more socket, so it has no such limitations. -Dave -- Dave McGuire, AK4HZ New Kensington, PA