Back when garage door openers and remotes were new shiny things that not everyone had I recall our TV being turned off and on a few times. We were afraid it was the demons to be sure until we figured out that garage door openers ( at least at that time) could interfere with a TV signal.
Also once heard a phone call made from a private home to a business on TV. I copied down the number and called the business to let them know I had just heard a phone call to their number. It was 1969 so who knows how that happened.
I bet a lot of demon stories are just electronics gone wild.