Abstract: An operator panel for a data input unit has a printed circuit board on which key switches corresponding to a number of commodities are arrayed. A flexible sheet is bonded over the keytops of the key switches. Photographs depicting the external appearance and shape of the commodities, or sketches showing the characteristics of the commodities, are printed on the flexible sheet at positions overlying respective ones of the keytops. The sheet has enough flexibility to enable operation of the key switches without hindrance. To input data relating to a desired commodity, an operator finds the photograph or sketch of the commodity on the flexible sheet and presses this portion of the sheet, thereby pressing the underlying commodity key switch to effect the entry of the data.