I am unsure if this is the right community but here it goes.
I want to buy a smart TV and I will plug a HDMI device into it. I want to stream my games and movies to the TV via moonlight/jellyfin. I heard about ACR and how it can be used to recognize content running on our TV which will be then sold off to advertisement companies/data brokers.
Say I have isolated the traffic of the TV (the OS of the TV specifically) to a separate VLAN. But the connected HDMI device is connected to the internet. Can the TV use this network to effectively “phone home”? Do HDMI devices have this capability?
PS: I know modern HDMI dongles can also share data but I at least have the option to change the device/use a mini PC.
It’s very very unlikely that your TV and your device connected to it both support and enable ethernet over HDMI by default. But if you are unsure you can test it by connecting and seeing if the TV is getting a connection.
Personally I also opened my TV and disconnected the wifi card since in theory the TV could also just try to connect to any open wifi in the area without me knowing, but to each their own threat model.
I might be a bit paranoid but I suspect that in such a scenario, the TV will report that there is no connection but will keep on sending data to remote servers.
Fortunately in my area there are no open WiFi networks but disconnecting the WiFi card is a good suggestion. Wish we had physical kill-switches in all devices.
You can sniff the network and see if the TV is connecting anywhere.