In the SNPViewer dataplots, what are the units used on the X and Y axis?

SNPviewer produces a Cartesian plot of the FAM and HEX data, using values that have been normalised using ROX passive reference dye. The scale represents fluorescence intensity units from our BMG PHERAstar plate readers. These intensity values are arbitrary, with FAM values plotted on the X axis and HEX values plotted on the Y axis. Due to the differences in FAM and HEX excitation and emission peak heights, there is a slight skew towards FAM that is reflected in the minor differences in scale values for each axis.