Connecting old HTS 2600 surround sound to smart tv

[acase]

I have a Hisense smart tv and surround sound without hdmi. Both the tv and surround sound have a digital output/input. I bought a digital optical cord and the sound does not come out when I play channels on the tv but does when I play a DVD. Can I use the surround sound when watching regular tv channels?

 

[americanaudiophile]

Try changing the audio output type in the TV menu.

 

[acase]

Try changing the audio output type in the TV menu.

I tried to change the output type on the TV and it did not change anything. The digital optical cord has a red led light on the end where it plugs into the surround sound. I cannot find any information for the HTS 2600 RCA surround sound anywhere online. I worked on hooking it up for 2 hours the other night and still stumped.