The default graph is referred to as an interval plot because the x values of the plotted series are always spaced apart by a numerically constant interval. By default, this constant interval is expressed as a unit of time. Also by default, the interval does not explicitly store each x value since any x value is determined from the x-offset (i.e., the starting point) and delta x (i.e., spacing) parameters.
You may choose the default graph type by changing the Series Configuration under the Tools, Configuration pull-down menu, or by setting the PLOT_STYLE parameter in the DADISP.CNF file. See Appendix B, "Modifying the DADiSP Configuration File" for more information.