In addition, pinholes and local damage plastic sheath may result in moisture from entering the cable core, the cable electrical characteristics deteriorate. It further found that the cable jacket damage is not necessarily the place where the transmission characteristics deteriorate, which gives the cable maintenance and troubleshooting a lot of trouble, so in the manufacturing process of the cable, usually three ways to ensure moisture-proof and waterproof cable that is inflated or filled with petroleum jelly using super-absorbent material, which with petroleum jelly at home with a little bit more common. Petroleum jelly filled cables, fiber optic cable all the gap, among waterproof seal plays the role of the optical fiber from the external environment, extending its life, and no maintenance can maintain long-term stability and reliability of fiber optic transmission.