Screening

Screening is used to reduce the effects of electromagnetic interference (EMI) or electrical noise which can disrupt the transmission performance in some environments. This noise may be as a result of external interference from other electrical equipment or as a result of interference generated within the cable from adjacent pairs (cross talk).

Screens can be:

Aluminium/polyester tape

with a tinned copper drain wire, the most popular construction

Copper/polyester tape

with a tinned copper drain wire, for a better screen effect

Bare copper braid

for electromagnetic interference or when the cable is subject to movements

Tinned copper braid

for electromagnetic interference in presence of corrosive atmosphere or high temperature