Most modern TV's now only have a digital optical output rather than the 2 x RCA. Most of our radio systems only have an RCA or 3.5mm input such as the Systemline E200.
In order to connect your optical out TV to a stereo RCA or 3.5mm input you will require a digital to analogue audio converter.
This little device converts your input device i.e TV (connect via TOS Link or Coaxial) and converts it to stereo L&R RCA connections.
You simply connect it to your TV via an optical lead connected to the "input".
You then connect the digital to analogue audio converter to your analogue radio system with an RCA - RCA cable or an RCA to 3.5mm jack lead depending on the inputs available on the device you're plugging into.