In Europe, as many as 200 homes are fed off the same transformer. If they all access the Internet at the same time, they divide the 2 megabit speed, making actual transmissions much slower. In the United States, where transformers are connected to as few as four houses apiece, the transmission speed would hold up better. But hooking up the special adapters to each transformer would be expensive. Ocala, Fla.-based Intellon has tried to address this problem by making adapters for use in the home.
People plug their regular phone line into the adapter and then plug the adapter into a wall socket.
That turns the home's electrical wiring into a miniature local area network, and people can plug their phone into any wall socket, using another adapter. Larger companies also are interested. An industry umbrella group in the United States called Home Plug has received strong backing from such companies as Cisco Systems, 3Com, Intel and Compaq Computer. Powerline also faces regulatory hurdles in countries including Japan and Israel, where the power industry is strictly separated from the telecommunications industry. The technology has roots going back to the 1940s, but until recently, it was nearly impossible to transmit data signals over electricity wires because of spikes, ebbs and surges which would disrupt the flow of data.