Composition Of Jelly Filled Telephone Cables
TK 110 A 91 (S/WT -143 B Revised) of Indian
Telecommunication Department

Conductors: Drawn from high quality electrolytic copper of not less than 99.9% purity conforming to IEC 28. Standard Conductor sizes are 0.32, 0.4, 0.5, 0.63 and 0.9 mm.

Insulation: Insulation is done with Medium/high density Polythylene in Tandem High Speed Telephone Wire Extrusion Line with highly sophisticated Computerised System to control for diameter and coaxial capacitance of the wire.

Twinning: The wires are twinned in the specified colour combination at different pre-determined lay lengths to minimise cross talk attenuation.

Stranding: 10 pairs and 20 are stranded as single unit. 50 pair and 100 pair cables are formed by stranding together five Subunits of 10 pair or 20 pair respectively. Super units of 50 and 100 pairs are stranded together for higher pair cables.

Jelly Filling: The interstices in the stranded core are fully filled under pressure with suitable water resistant filling compound. The filled core is then covered with polyester tape of high dielectric strength.

Shielding: Co-polymer coated Aluminum tape is applied in the longitudinal direction and sealed for electrical shielding and to form a moisture barrier.

Sheathing: Sheathing is done with black low density polythene to the required thickness.

Mechanical Protection: The Sheathed Cable is given a bedding by application tape. Two galvanized steel tapes, both applied helically with a gap of 25+/-10% of the width of the tape : the second tape evenly covering the gap of the first tape.

Final Jacketing:The tight fitting jacket of vergin low density polythene is extruded over the armouring to form the finished cable.

Final Testing : Each drum is tested for conformity of electrical parameters in computerised Automatic telephone Cable test Set with print out facility.