Tributaries - 4AO - Series 4 Fiber Optic Audio Cable (Single) Tributaries Series 4 Fiber Optic cables are single mode plastic optical fiber made from 1mm crystal-clear fiber cores surrounded by a highly reflective cladding and a protective jacket. The cladding and jacket are applied in concentric layers during the drawing process to prevent damage to the fiber that may occur during a 2 step process. The constant thickness improves losses due to attenuation. The 4AO has highly polished termination ends that resemble the convex look of a camera lens to ensure maximum signal transfer. This procedure ensures less than 0.1dB loss at each termination. The 4AO is terminated with Toslink SJ15 connectors. The plastic optical fiber is first protected with a gold-plated collar and then polished into a perfectly convex lens. The assembly is inserted into the Toslink connector and then molded to protect the connection and give an attractive appearance.