Example Cross Section - CAT5 FTP PE
SFX Cat5E FTP
4 Pair, 24 AWG, solid bare copper wires with a differing and precise number of twists per metre to reduce crosstalk between two pairs. HDPE insulation. Overall (AL-PET) foil screen.PVC, LSZH or PE Jacket.
Screened versions are used where proximity to RF equipment may produce electromagnetic interference. It is also used as a security measure should eavesdropping be apparent.
There are various screening options available dependancy on enviroment and application. Please see table below.