An etchant composition for etching a transparent electrode is provided, the etchant composition includes an inorganic acid, an ammonium -containing compound, a cyclic amine compound, and the remaining amount of water. An information code such as an address or control data for a particular data signal at a selected wavelength is overlaid on the parallel multiplexed signals. A telemetric communication device telemetrically transmits data related to a parameter sensed by the sensor to a remote device. Using that information, together with the probability that any given slot will actually be occupied by an interfering transmission, a statistics package may be developed which gives an indication of the probability of a transmission from the interferer at any given time. The exhaust gas treatment system further includes a reductant quantity control module configured to generate a pre-control parameter that modifies the initial control parameter based on the quality of the reductant solution. 1% of a magnitude of the fundamental frequency component, respectively.