Unibus Termination KnowledgeQuest
jwest at classiccmp.org
Fri Oct 13 09:52:09 CDT 2006
> I know that I have a working 11/35 (/40 OEM) which has an M9312
> in the last slot (unibus-out). That was 3 years ago, and when I am
> up to inspecting the /35, I will sure check the M9312 jumpers!
> The 11/35 documentation mentions M930 as terminator at the "far"
> end, and I (in my ignorance some years ago) said, just like Jay, "hey,
> the M9312 is also a terminatoe, so...". The bottom line is that my 11/35
> did work with the M9312 at the far end of the unibus, and that I could
> start the system, and enter "DL" to boot from RL02.
> Now, if everything was electrically correct (for example not terminating)
> is something I will certainly check when I get to it.
Henk, I believe you are right. The /35 doesn't have the cpu doing this
("partial") termination like the /04 and /34 does I don't think. So your
situation for termination is likely to be more similar to mine in the /45...
where you typically have a M930 in slot 1AB, and then another M930 in the
last unibus out AB slot. To install a M9312 in one of those type of systems,
I believe you can replace one of the M930's with the 9312.
Given that my background was the /45, I found the situation with the /34
most confusing - hence my post to the list.
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