Norden Internal Multi-pair Telephone cables are manufactured in accordance with BT type CW 1308. These cables are used for connecting telephone systems and data exchange systems with a plain annealed copper conductor of 0.4mm, 0.5mm, 0.6mm &; 0.9mm diameter with PVC insulation. These are twisted to form a pair and over sheathed in white, cream, gray &; black PVC. A rip cord is laid under the sheath to facilitate its removal. An optional 1.38mm diameter earth copper wire is available on 50 pair cables and above.