Telephone Wire

Each conductor consists of a round wire of annealed high conductivity copper.
Each conductor is insulated with solid mediumhigh density polyethylene insulation.
Two insulated conductors are twisted with uniform lay to form a pair. The length of the lay of the pairs is so chosen that the cross-talk is minimum.10 or 20 No's of twisted pairs are laid up to form a group which constitutes a unit. Each unit should have an overlapping for color ID. In case of cables having more than 100 pairs, 5 units of 10 pairs or 20 pairs are laid up to constitute 50 or 100 pairs of super units respectively.