High-frequency symmetrical trunk communication cables for analogue and digital transmission systems ????????

1 Conducting cores - single-wire from copper soft round wire.
2 Insulation of cores in a quadruple - film-porous-film, three-layer: a layer of solid polyethylene, a layer of porous polyethylene, a layer of solid polyethylene. Insulation of auxiliary cores is made of solid polyethylene.
3 Quadruple - cores with insulation of different colours are twisted in a star quadruple around the central cordel made of polyethylene composition. In a quadruplet, two conductors arranged diagonally form a working pair. The insulation of the cores of the first pair of quadruplets is coloured red and white, the second pair blue and green. The twisted fours are wrapped in an open spiral with coloured cotton yarn of different colours.
4 Core:
- of a four-quarter cable - twisted from four star fours;
- seven-quarter cable - twisted of seven quadruplets, five auxiliary pairs and one auxiliary core.
5 Belt insulation - made of cable paper tapes, polymer film.
6 The measuring tape is laid under the belt insulation...