24.2 Categories

     The various errorlevels can be organized into four basic
     categories:

     Mail received       When mail is received, you can choose to exit
                         to the batch file to run external mail
                         processing utilities, such as TosScan, etc.

     User break/errors   When you press <Alt-Q> from the FD's main
                         menu or when errors occur.

     BBS calls           If you are running a BBS under FD, it is
                         necessary for FD to exit with an errorlevel
                         indicating the baudrate of the call. The line
                         is still active when FD exits to the batch
                         file, the BBS software is loaded and the
                         caller will be able to access the BBS.

     External events     The errorlevels defined in FDSETUP's event
                         manager.