Examples:

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.