Patent ID: 7227462

Claim:
A method for simultaneously polling a plurality of electrical meters located at premises to which electricity is supplied through an electrical distribution system to determine the status at a location within the system comprising: transmitting a query signal from a transmission site over a power line to poll each meter comprising a group of meters to which a query signal is sent; all of the meters in the group simultaneously sending a reply signal back to the transmission site over the power line, each separate reply signal having a predetermined orthogonal bit pattern N bits in length and derived from a Hadamard matrix, the bit pattern for each meter being a unique bit pattern that is non-interfering with all of the other bit patterns sent by all of the other meters; and, receiving the reply signals and processing the bit patterns comprising each reply signal to determine the status at each location of a polled meter, the information conveyed by each bit pattern being the presence or absence of a response from each meter in the group of meters polled with the absence of a response from a meter indicating a power outage at the location of that meter.