The simple setup costs only about $600 to build and employs the green and red laser pointers typical to the conference room presentation. By replacing the batteries in the lasers with a power sources that can switch them on and off rapidly--500 million times per second rapidly--a two-laser rig can beam a billion bits per second across roughly 30 feet (that was the distance in a recent demo, anyhow) wiht an error rate of less than one bit per billion, New Scientist reports.