indoor telephonecable1.Conductor:Adopt soft round copper wire as conductors, whose diameter includes 0.5, 0.6. 0.8mm2.Insulation:adopt one of flame retardant polyethylene,PVC and polyethylene according to different moel,3.Line pairs:every two insulation conductor strands into pair according to the stated chromatogram.4.Sheath :the technical spec of PVC sheath material is up to the standard of GB88155.Indoor telephone cable and outdoor telephone cable,Type for HYV,HYY,HYYC