A method and device for decoding a sequence of signals in which information is derived, in part, from a duration of one of the signals andor an inter-signal pause between two of the signals. An interface is provided in order to call a function on the transaction system for performing the transaction. A multivariate multistage background model comprising a first model that models a first time effect, a second model that models a second time effect that is different than the first time effect, or both is calculated. The method makes it extremely difficult to find the information in the samples if the proper keys are not possessed by the decoder. A third dielectric layer with a second conductive feature overlies the second dielectric layer, forming a conductive pathway down to the top surface of the metallized bilayer over one of the sourcedrain regions or the gate electrode layer.