The RS-232 handler isn’t resident in the Atari OS. It must be loaded from disk.- turn on the 850 interface, then boot from the Atari DOS Master Disk or from a disk containing the AUTORUN.SYS file (from the Master Disk). This loads the RS-232 handler and adds its address to the handler table. Then simply use the RS-232 port as another I/O channel First, OPEN #1,8,0,”Rl:”, then use PRINT #l or PUT #l to send data to the port. Finally, CLOSE #1. Of course, this can only be used to modify BASIC programs that use the printer Modifying machine language programs that use printers, such as LJK’s Letter Perfect requires extensive technical expertise and probably wouldn’t be worth the trouble.
As far as we know, the only commercial word processing program for the Atari using the RS-232 port is Atari’s own Atariwriter. Choose SAVE from the main menu, then type R1: at the prompt for device and file name. If you use Atariwriter without a disk drive, the RS-232 handler is automatically booted if the 850 is turned on and connected before the computer is turned on.