Patent ID: 8290635
Filing Date: 2012-10-16
Classification: H02J,H04B

Abstract:
1. A method comprising: outputting a time-finite electrical signal together with an electrical power signal via an electrical power outlet onto an electrical appliance connected to the outlet; measuring a set of electrical parameters of the time-finite electrical signal affected by the electrical appliance, at the electrical outlet, being an electrical signature of the electrical appliance, wherein the electrical signal is uniquely associated with at least one state of operation of the connected appliance; and analyzing the electrical power signal at the outlet over time, by determining time periods in which the power signal is associated with the electrical signature, to yield at least one of the following: an indicator that the appliance is connected and operating; an indicator that the appliance has been shut down but remains electrically connected to the outlet; an indicator that one or more appliances has been electrically disconnected from the outlet; an indicator that an appliance has been disconnected from the outlet and later re-connected; an indicator that the appliance has been replaced with a different appliance at the same outlet; and an indicator that at least one additional appliance has been connected in parallel to the appliance, via the outlet.