Depends on the network and provider you have. Verizon's FiOS uses a coax line to both the TV and the Internet Modem. Something about the TV messes with the Internet if you are not using Verizon's set top box. If you put in a low pass filter (LPF) it removes the interference and everything works properly. Another thing you can do on Verizon FiOS is to have the connection to the Internet modem changed from coax to ethernet and the problem will go away. That is what I did in the end, though I used a LPF for a long time before then.