Electronics watchdog

Burglars should be less likely to steal electronics equipment if they know it will refuse to work once it leaves home. At least, so reckons French company Thomson, which has filed a patent application for a system that keeps watch over every piece of electronic equipment in a house.The watchdog device would contain a secret code and could be hidden somewhere in the house or inside an apparently ordinary domestic appliance. Every electronic gadget in the house would also include a circuit that communicates with the watchdog device via electrical pulses sent over the mains system.When a new piece of equipment is brought home and plugged in, it would automatically pick up the watchdog code. From then on, every time it is switched on, the device will checks that it can still pick up the code and only work if it can.If a thief steals any piece of protected equipment it will refuse to work when plugged into a different mains supply. The only way to beat the system would be to steal the watchdog device too, which means stealing everything that is plugged into the mains. It's not clear what you ought to do if you want to take your TV over to a friend's house though.