Telephone cables with film-porous-film insulation, in

1 Conducting cores - single-wire from copper soft wire. 2 Insulation - film-porous-film (three-layer, consisting of solid, porous and solid layers of polyethylene). 3 Pairs - twisted from insulated conductors of different colours.

Pairs are twisted into five or ten-pair elementary bundles. 4 Core - twisted from elementary bundles of different colours. The free space of the core is filled with hydrophobic filler.

5 Belt insulation - overlapped polyethylene terephthalate film, overlapped polypropylene uniaxially oriented film. A layer of hydrophobic filler is applied on top of the belt insulation. 6 Shield: aluminopolyethylene tape laid longitudinally.

A tinned copper wire is laid longitudinally under the shield. 7 Sheath: polyethylene. 8 Protective cover - of two tapes of crepe paper, overlapped, layer of bitumen, two steel tapes, overlapped with a gap, layer of bitumen, glass yarn, layer of bitumen, paraffin, chalk cover.