sourcefile

     The file specification of the conversion source file.  The
     default file type is .ISRC.  The file naming convention OpenVMS
     uses for conversion source files is:

     fromcodeset_tocodeset.isrc

   tablefile

     The file specification of the conversion table file to be
     created.  The default file type is .ICONV.  The file naming
     convention for conversion table files is:

     fromcodeset_tocodeset.iconv

     Public conversion table files are in the directory defined by
     the logical name SYS$I18N_ICONV.  Put new conversion table files
     in the same directory if you want to make them available
     system-wide.