<   This leads to the following question for Tim and others. Since
<apparently the original Q18 backplanes were Q/CD, the original quad-widt
<Q18 cards didn't have grant continuity etches on the CD half, did they? 

Yes they did.  I happen to have a BA11N with a Q/Q backplane installed
and cards like RLV11 are unusable due to lack of Q/CD but RLV12, m8012,
11/23, 11/73, DHV11, DZV11 and others all work.  They have jumpers to pass 
grants on the cd connector is they are Q and not CD.  The exception 
RQDX1/2 as it doesn't pass grants on the AB-CD at all.  
  
<intention was to allow the first card to have connections on the right si
<but not to allow the last card to have connections on the left side, and 
<only MicroVAX II reversed this. Does anyone have an idea?

Retrorevsionist history.  Look at say a 1978/79 or 1979/80 or 1982 copy of 
the Microcomputer Interfaces Handbook.  It was already sorted out by then
with the Q-22 KDF-11B PDP-11/23B in 1982.  Before the microvax the J-11 
cpu KDJ-11 was also Q22 and followed soon after by PMI for the PDP-11
(J-11).  Anyhow the rules for Q/Q and Q/CD backplanes were already laid 
down well in advance.  I should point out that the CD side for non Q/Q
backplanes can be wired in any way desired with only power and ground 
being standardized and I have at least three Q/CD backplanes wired 
differently for the CD side.


Allison