The extracted orders in the pixel domain can be resampled into wavelengths with the command REBIN/ECHELLE. Several quality checks are provided by the command IDENT/ECH. Residuals are visualized with the command PLOT/RESIDUAL. A method to verify the wavelength calibration consists of extracting and resampling the wavelength calibration frame and displaying the resampled image with a large scaling factor on the Y-axis. The variation of wavelength coverage from one order to the next should be smooth. Different regions of the resampled image and in particular the overlaps can be verified with the command PLOT/SPECTRUM.