TVs that are equipped with Fire TV OS do come with an optical cord and optical port for sound output through which you can connect the soundbar. If you are referring to the Fire TV stick instead of the complete TV like Insignia Fire TV or Toshiba Fire TV : To use Optical output, you need to connect the TV to which your Fire TV Cube is connected to the soundbar using a TosLink Optic cable. This means that the TV you connect your fire tv stick to should have an audio connection using a fiber optic audio out.