POWER FLEX Telephone and Switch Board Cables are made of high conductivity electrolytic grade annealed bare copper conductor with nominal diameter of 0.4 mm and 0.5 mm. Special grade PVC at per 15:13176 type 2 is used for insulating with proper colour codes. The insulated cores are twisted together with suitable lay to form a pair The pairs are bunched together to form pairs in such a way to avoid any cross talk