Q5: And geometry–ribbon, twisted, braided, spiralled? Why shielding? Why not shielding?
The Twisting process is used when there are more than 2 cores, The benefit of twisting is to neutralize the electromagnetic field between 2 or more cores ; another function is to make the cable round shaped like normal cable.
Braiding & Spiraling & Shielding :
These three processes are about isolating and reducing the EMI(Electro-magnetic Interference) and the RFI(Radio Frequency Interference) , which help to lessen signal loss and noise-free.