UNIBUS extension card/cable sets

Ah, hadn't noticed that! But then again, I hadn't looked at them closely yet! :-) Yes, they do connect to ground - all the UNIBUS ground pins are ganged together, and connected to the A-row Berg pins on all 3 connectors. So every other wire on the 40-conductor flat cables should be ground - that's even better than the classic BC11A, where almost every other line is, from what I can see, simply left floating (which is better than nothing, but not as good as grounding them, is my understanding). 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', so... I just couldn't find out _anything_ about M9015's, so I was just guessing in the dark. Real data gratefully received. Hmm. Well, I dunno; that may be beyond my (minimal :-) level of analog expertise. I would have assumed that it's the _change_ from one impedance level to another that's the issue (you can get a reflection off the junction), so whether one's using long or short cables between a pair of M9014's, it shouldn't be _that_ big a deal (modulo propagation delays, which _are_ an issue with length). Perhaps someone else can opine? But I hope we can do fairly long runs with the 40-conductor (aka BC05L-xx), that could save us when we run out of BC11A's, if that strange Flexprint flat white cable the BC11A uses is no longer available. Noel PS: From what I can see so far (done half the pins), the M9014 and M9042 do have an identical pinout on the Berg connectors.