Another place where there is a sea of 2901s is the FPU for the 11/23b. I have one of those too. Glad to be back. Spent 5 years working for a firm that makes P-RTDs as their sole IS/Net/Server/DB/engineer person and was plain too busy for life until.. they sold it. Now I have way too much time till I get mixed up in something else hairbrained. Still have VAXen, PDP-11s, PDP-8s, and a raft of S100 hardware. I plan to put a T-11 in a smallbox with a 640x480 mono lcd and keyboard and run RT11 on batteries with it. I be tired of washin winders. Allison KB1GMX VHF/UHF and out there.