Above is a picture of the ‘innards’ of a SNAIC-4 (it was quite difficult to get even this far…).
Looking down inside the DIN shroud, I can see a 5th conductor, chopped off (so I guess SNAIC-5’s and SNAIC-4’s are both made of the same 5-way cable) - and I can see a Screen.
What I cannot say is if the Screen is terminated - it is not at the end shown above.
So is it ‘screened’ or not…? It looks like the Screen istself isn’t used - but the cable is of 5 way twisted construction, so is effectively ‘self screening’ - any Common Mode efects will be cancelled out.
No SNAIC’s were harmed in the process of producing this message… 