1 Turn off the power to the audio amplifier or receiver, and the source component. Upgrade your audio system with our step-by-step guide. Your purchase of these products through affiliate links helps to generate commission for. In this step-by-step guide, we will walk you through the process, ensuring that you can seamlessly connect your optical cable and enjoy a clear and uninterrupted audiovisual experience. Optical cables are becoming increasingly popular for transmitting high-quality audio signals between devices. To use a fiber optic audio cable, you'll need to connect it between compatible audio devices to transmit sound digitally. You're looking for connection ports that are square with rounded bottoms; they may be labeled "Optical" or, sometimes "Digital".