Pretty simple actually - and nearly every output has a way of doing this.
In order to get the sound from the TV to the laptop - the simplest way would be to use the AV port - you can get an RCA to 3.5mm TRS cable and just connect the sound outputs of the AV jack directly to the PC.
Alternatively, you'd need to find a device that converts the SPDIF out (depending on what's the interface - optical or co-ax, your options would vary) to analog, and connect the appropriate.
There's also devices called HDMI audio extractors (and I found this by wild googling) that would split out the sound into different outputs and pass through HDMI.
You'll then need stereo mix or monitor support in your sound card. This is uncommon these days and you might need a seperate bit of software to do this.
voicemeeter banana seems to do this on windows(along with other things.) They might actually have simpler software that might have the same effect, but I've gotten this to work in the past.
You'd need to pick your audio in as the input device (not set as such here) and pick your speakers as the output, and not turn on mono mode for the output as shown here. Needs a bit of messing around, but should do what you need.
@mael', actually it's not from tv to laptop, more like from the interface of the router to laptop. – mathmaniage – 2019-06-25T00:55:11.317
1There is no way, not via its outputs anyway. Depending on the box's OS/software you may be able to create some network share. – None – 2019-06-25T00:55:41.123
@GabrielaGarcia , not via it's output, meaning, the tv box or the router? – mathmaniage – 2019-06-25T00:57:30.870
feel free to edit your question to state that; the way it was originally written made it sound like the ethernet bit was superfluous or just there to add an avenue for indirect solutions. – mael' – 2019-06-25T00:59:10.110
1
Vaguely, and very vaguely almost a dupe of this - there's a few more fiddly bits once you get the sound into the PC though...
– Journeyman Geek – 2019-06-25T01:02:40.513