Supposedly the EMP pulse has the potential to strike all computerized and electrical devices, plugged in or not, unless they are sheilded or protected by something like a Faraday Cage.
An EMP can travel through the air and impact stand-alone devices like auto computers, cell phones and radios. Or it can enter a conductor, like grid power cables and wires, and travel through them to strike devices plugged in, like TV sets, home computers, etc.
OK, thanks for the info.