TheDrive and its partners may earn a commission if you purchase a product through one of our links. Read more. If you want to connect an external device—such as your smartphone—to the audio system in your vehicle, one way to do so is with a top-rated aux cord. It can be used for a number of electronic devices to play music and other audio files. Check out our aux cable reviews to find the best 3.5mm cable to suit your needs. A 3.5mm aux cable is a standard for stereo input and output. It can be used with a compatible jack or auxiliary input to link an audio source to your vehicle’s stereo system. This cable can be used with cell phones, portable MP3 players, portable navigation devices, remote mount DVD players, or other electronic devices. An optical cable sends a raw digital signal, while a standard 3.5mm cable sends a converted analog signal. An optical cable is higher quality. A 3.5mm cable cannot be used in a fiber optic input/output, and a fiber optic cable cannot be used in a 3.5mm input/output. They each require different cables and connectors. Optical cables provide less interference but are more expensive and less common than 3.5mm cables. Monster Cable Products...