In operating a display device incorporating a matrix addressed smectic cell, a strobing pulse is applied to each row electrode in turn while data pulses are applied in parallel to the column electrodes. The data pulse voltage excursion is less than the minimum voltage V T required to switch the cell. For the entry of complete rows the strobing voltage excursion is made larger than twice V r for fast data entry. For entry of rows in successive segments (e.g. for single character entry) the strobing voltage is of longer duration and is less than twice V T so that successive strobing pulses applied to a single line cannot give rise to spurious switching of unselected pixels.