XSPEC> dummyrsp ! Create the dummy response with the default limits, initially .01, 100, and 200 bins.
XSPEC> dummyrsp .001 1 ! Create a dummy response with 200 bins that cover the range from .001 to 1 keV.
XSPEC> dummyrsp ,,,500 ! The same range, but now with 500 bins.
XSPEC> dummyrsp ,,,,lin ! The same range, but now with linearly spaced bins.
XSPEC> response ! Restore any previous correct responses.