The U.S. Court of Appeals for the Federal Circuit upheld a rare patent victory in favor of Eastern District of Texas defendants on Monday, dismissing Paradox Security Systems Ltd.'s infringement suit against ADT Security Services Inc. and others over home security system technology. The Federal Circuit agreed with the U.S. District Court for the Eastern District of Texas that Paradox, a Montreal-based security services provider, had failed to provide enough evidence of infringement once a portion of its expert testimony was excluded from trial. Paradox filed the lawsuit in November 2006, claiming that ADT and the maker of the accused products, Digital Security Controls Ltd., infringed on patents that cover a device that protects the circuitry in a home alarm system from power surges, specifically in home security systems that communicate with central security offices via telephone, according to the opinion. With the expert testimony lacking, the judge ruled that no reasonable jury could find the defendants, ADT and Digital Security, liable for infringement based on the evidence in the record. ADT and Digital Security are represented by Finnegan.