28 Nov
2016
28 Nov
'16
7:14 a.m.
On Mon, 28 Nov 2016, Noel Chiappa wrote:
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.
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. 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