> On Jun 25, 2015, at 2:01 PM, Noel Chiappa <j...@mercury.lcs.mit.edu> wrote:
>
>> From: Paul Koning
>
>>> Right, but the very similar QBUS does have terminations (of a sort -
>>> the rules for when you need terminations on QBUS extensions are so
>>> complex that I don't really grok them yet) 'in the middle'
>
>> That doesn't seem likely. ... the definition of 'termination' is
>> something that you learn in EE 101 and are unlikely to forget.
>
> I agree with your sentiments, _but_ all I know is that if you look at,
> e.g. the 1982 'microcomputers and memories' handbook, pg. 251, you'l see a
> three-backplane system, with terminations at the start _and_ end of the first
> backplane (and also at the end of the third backplane).
What’s between the backplanes? If it’s a repeater, that would be correct
(because you have two separate transmission lines). If it’s a cable, then this
is wrong. But as Tony said, it might be that it’s not so wrong that things
break, thanks to the small scale and slow speed of Qbus.
paul
