[cctalk] Positive Logic vs. Negative Logic Controller in DEC TU56

I am working to understand a TU56 in my possession that came from an unknown environment. A connecting cable that came with it reads "PDP9" on one end so I wondered if this is actually associated with the TU56 or just sitting in the same box before the TU56 came to me. I have read here: https://gunkies.org/wiki/TU56_DECtape_Transport That one can have a TU56 with a M531 or a G742 to serve as a bus converter. THe M531 is for situations where one has a negative logic controller and the G742 is for when one has a positive logic controller. Jumping a few steps ahead, if the TU56 was attached to a PDP-9, would it use a G742 if one tried to attach a TU56 to it? I feel as if the G742 would be used if the TU56 was intended for a PDP8 and not a PDP11, right? I searched the web and will continue to research but I thought I'd ask experts here. No, I don't use ChatGPT. Bill