Main.net's system skips the high-voltage lines, injecting data into the grid further downstream, on medium-voltage (4, 000 to 25, 000 volts) lines.

FORBES: Technology

Local controllers (X-NET) gather this information and deliver to a web-controller via GPRS. The overhead sensors are line powered, and the X-NET Controller can be powered by a low voltage supply or a solar panel.

FORBES: GE Gobbles Up More of the Smart Grid