On Mon, 28 Nov 2016, Noel Chiappa wrote: > > However, I don't have the cables necessary to attach a QBUS expansion. > > Does anyone have a set? What do they even look like? > > They are a pair of boards connected with a pair of 50-pin cables. The boards > are different on each end, because the QBUS does not have in/out connectors > which separate from device slots, like the UNIBUS; it only has regular QBUS > slots, and those have grant in on different pin from grant out. So on the card > at the end of one backplane, the grant line is connected to the 'grant in' > pin, and on the other card, to the 'grant out' pin.
FYI, the VAX 4000-100/105/106 (KA52/KA54/KA54) systems have no backplane of any kind and do not use Q-bus internally, except for the CQBIC (CVAX to Q22-Bus Interface Chip) ASIC directly bridging one of the NCA (NDAL to CDAL Adapter, or the north bridge in modern speak) ASIC's CP peripheral buses to a mainboard Q-bus connector further wired with an internal cable assembly to the pair of external connectors mounted on the backside of the enclosure. > As to finding a set, there are some available on eBait at the moment for a > not wholly unreasonable amount of money. For the record they are DEC P/N BC04V-09 (17-02048-01), though the photos with the only listing I could find indicate quite a sorry state of the cables offered I'm afraid. Maciej