An audio-visual educational device including a housing including a plurality of separate viewable indicia each representative of an object which produces a distinctive audible sound associated with the corresponding object. In particular, the present invention relates to power consumption reduction by providing two operation bandwidths for a terminal, one being a cell-bandwidth, a bandwidth in which the cell may operate and the other one is a bandwidth, lower than the cell-bandwidth and called power-saving bandwidth. A method of making is disclosed wherein carbonization occurs at a temperature of less than about 600\xb0 C.