J: Optical fiber tight covering structure, E: Elliptical shape, T: Filled structure JET outdoor fiber optic cable, 250Î¼m, either of single-mode or multi-mode type, are positioned in a loose tube made of a high modulus plastic. The center of the cable core is a non-metallic reinforcing core (FRP) and reinforced core with water blocking yarn A layer of aramid yarn or high strength glass is applied around the cable core as additional strength member. The tubes are filled with a water-resistant filling compound. Then, the cable is completed with a black or color sheath.The original overhead line is used for long-distance communication and inter-office communication lines. Different types of aerial cables are suitable for hanging wire and self-supporting.