Home computers could soon connect to the Internet through electrical power lines that would supply data faster than a phone line. Northern Telecom of Canada and Norweb Communications in the UK say that they have transmitted data at speeds of up to one megabit per second - the same speed as an office computer network - using electrical power lines. The systems relies on a protocol that can suppress noise in electrical cables.

Providing cheap high-speed telecommunications access to the home has been the goal of many companies over the past few years. The high cost of installing new phone lines such as ISDN has limited the expansion, as have the low availability of cable modems. This makes transmitting data over electricity lines very attractive.

The new system does have a significant limitation - the transmission protocol cannot cope with the voltage step-down at a substation. High-speed fibre-optic lines must therefore be provided to the substation. Another problem is that as the number of users increases, the speed of the network drops to about 500 kilobits per second.