Cable Jacket: The outermost layer of protection for the fibers which is chosen to withstand the environment in which the cable is installed. This layer is made of heavy-duty materials, such as polyvinyl chloride (PVC), polyethylene (PE), or thermoplastic. A fiber optic cable consists of five basic components: the core, the cladding, the coating, the strengthening fibers, and the cable jacket. These cables are used mainly for digital audio connections between devices.