If you've read How Internet Infrastructure Works, then you understand that the Internet is physically a huge network of networks that are connected through cables, computers, and wired and wireless devices worldwide.
Typically, large ISPs lease fiber-optic lines from the phone company to carry the data around the Internet and eventually to another medium (phone, DSL or cable line) and into your home. Trillions of bytes of data a day are transferred on fiber-optic lines because they are a stable way to transmit data without interfering with other types of transmissions.
The idea of using AC (alternating current) power to transfer data is not new. By bundling radio-frequency (RF) energy on the same line with an electric current, data can be transmitted without the need for a separate data line. Because the electric current and RF vibrate at different frequencies, the two don't interfere with each other. Electric companies have used this technology for years to monitor the performance of power grids. There are even networking solutions available today that transfer data using the electrical wiring in a home or business. But this data is fairly simple and the transmission speed is relatively slow.
BPL technology developers Current Communications Group and Enikia are working with power companies like Ameren and EPRI to get BPL off the ground. There are several different approaches to overcoming the hurdles presented when transmitting data through power lines. The details of these approaches are still pretty closely guarded secrets as both companies vie for the FCC's and IEEE's blessing for having their method adopted as the standard way to deploy BPL.
In the next section, you'll learn the basics about the different approaches.