ACCESSWRITEHDS will, after closing any data file currently in use, open the output .cha file in order to write the ScanData, uncalibrated and calibrated, along with the configuration information. The file name is derived from the date, with an extension .cha. (If you restarted the session by reading the averaged data, the input file is closed first since it is identical with the output file and all files opened with the menu are read-only.) FITS will ask for a star to be written in FITS format. You have to run CALIBRATEVISIBILITYSETCOMPLEX before that in order to set the baseline phases.