Broadband Over Power Lines

Many people now access the Internet at speeds as high as 1 to 3Mbps over their phone lines using DSL or their cable-TV service using a cable modem. But DSL speeds drop dramatically if the home is more than a certain distance from the nearest phone company switching station, and cable-modem bandwidth can be reduced if there are lots of subscribers in the same neighborhood.

One alternative that could provide high-speed Internet access to just about everyone is called broadband over power lines (BPL). San Diego Gas and Electric is about to launch a pilot program that will offer some of its customers broadband Internet access over the lines that normally deliver AC power to their homes. Interestingly, BPL is a byproduct of the new system's primary goal, which is to provide a way for customers and the company to better manage their electric service. For example, the system will allow customers to monitor their electricity usage on a minute-by-minute basis.

But most important for home theater fans, BPL could provide Internet access at speeds up to hundreds of megabits per second, which would greatly facilitate services such as video on demand (VOD) and pay-per-view (PPV). Such services are difficult to implement, even at current broadband speeds, because of the massive amounts of data consumed by high-quality video.

On the other hand, power lines are notoriously noisy, leading some to compare sending data through them with driving a Ferrari on a bumpy dirt road. Not only that, A/V purists might object to having data signals—which amount to noise as far as the power signal is concerned—invade their AC lines (though power-conditioner companies might be delighted!). Only time will tell if these and other problems can be solved in a cost-effective manner, and experiments such as SDG&E's should help determine if BPL is a viable alternative to DSL and cable modem.