UNIBUS extension card/cable sets

tony duell ard at p850ug1.demon.co.uk
Thu Jun 25 09:25:09 CDT 2015

>    > If it's any help I pulled an M9014 out of the Unibus Out slot of my
>     > 11/730. There's currently an M9302 in there.
> Very interesting! Thanks for the data. This seems to indicate that the M9014
> could function as either end of the cable.

Somewhere I have the expansion box that went with this VAX. The thing is that I moved 
some items into a storage unit for the house move and haven't moved them back again. 
I suspect the expansion box was amongst them. When I get a circular tuit of a suitable type
I will take a look at what is in there.

The M9014 is just connectors. There are 3 40 pin Berg headers, one row of each appears to be
ground (or at least they're all joined together and if they go somewhere other than ground I
will be very surprised) That leaves 60 pins for the unibus signals. Of course power will not be 

> I was wondering if maybe the M9015 was an M9014 with termination resistors,
> or something (the way the QBUS versions come with and with termination), so

I would be very surprised. Unibus is normally terminated at the ends and not in the middle. I 
guess the 11/730 terminates the 'start', you put an M9302 in the 'end' 

I think I did read somewhere you could use a BC11A cable with the 11/730 (this does not surprise me),
so that would not have extra termination.


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