Re: What I'd hope ...
"I'd hope that someone is working on a seriously low-bandwidth protocol for commanding functions that are not safety critical, like on and off or up and down for light-bulbs, over the mains wiring of a house."
I already have this at home. It requires simple devices, placed conveniently adjacent to the doors of each room although there are exceptions where the devices are located on the ceiling and operated by a length of cord. The devices have a simple toggle action.
Biting the hand that feeds IT
