Your TV has toslink digital optical audio output.
A threaded coax connector will usually be for an antenna not audio.
If the HTS doesn't have optical in then you will need to convert it to be compatible.
If the HTS has an RCA jack (not threaded) labeled digital audio in then you would need to convert optical digital audio to coax digital audio,
If the HTS has an analog input (2 RCA jack or 1 mini jack) then you will need an optical to analog converter. If your TV can't be set to output in PCM stereo (check the manual or TV menu) then you will need one that's 5.1 compatible.