> On Mar 17, 2016, at 6:01 AM, Mattis Lind <mattisl...@gmail.com> wrote: > >>> > > If one read notes in the PDP-11/04 printset it says: Do not insert a M930 > or M9302 in a MUD slot. Only in the Unibus slots or you will have short > circuit. On the other hand it does not say that the M9301 (or M9312) cannot > be installed in a unibus slot. It recommends that those boards go into MUD > slots. But electrically I cannot see that it shouldn't work. Especially if > you jumper W1 - W5. >
Hopefully this will clarify a few things: “Unibus”: These are the AB connectors in the *last* position of a backplane. It allows for bridging between backplanes. The only “card” that can go these “slots” is a terminator (ie M930) or a terminator bootstrap (ie M9312). SPC: These are the CDEF connectors in any of the slots of a “unibus” backplane. Not all backplanes support SPC slots. MUD: These are the AB connectors in some newer backplanes (usually associated with the extra slots in a CPU backplane…11/34 and 11/04 CPUs have MUD slots). MUD stands for “Modified Unibus Device”. They are *not* compatible with Unibus slots as they have different voltages present than what are on the Unibus slots. You *will* “blow out” a board by plugging something designed for a Unibus slot into a MUD slot. TTFN - Guy
