For higher demands on cross-talk behaviour, the single pairs of a cable may be screened with laminated aluminum foils. By that, cross-talk attenuation values up to 100 dB can be achieved in the low frequency range. The screens can be contacted by a drain wire or strand.
Control cables with helical screen
In those cases, where cables are moved permanently, a foil screen may be a disadvantage. So, these cables are provided with pairs, helically screened by copper wires.
Thus, the cables are flexible and sufficiently screened for most applications.
