telephone cable: Inner Conductor: CU, CCS, etc. Diameter: 0.4mm/0.45mm/0.5mm Number of core: 2 core/ 4 core telephone cable: Inner Conductor: CU, CCS, etc.Diameter: 7*0.12mm, 7*0.20mmNumber of core: 2 core/ 4 coreInsulation: PE Sheath: PVCColor: White, Red, Gray, Black, Brown, etc