OS/2 2.0 and 2.1... MS-DOS Kermit can run in a window of OS/2 2.x and, of course, also in a full screen. Kermit's flow control has no effect because OS/2 itself is controlling the device. You can configure OS/2 to handle flow control itself by adding a command like the following to your STARTUP.CMD file: MODE COM1 XON=ON (for XON/XOFF software flow control) or: MODE COM1 RTS=HS OCTS=ON (for RTS/CTS hardware flow control) If your PC's communication port is a 16550A[FN] UART serial communication adapter (as is standard on the PS/2), it has a built-in buffer to improve performance. To enable use of the 16550's buffering capability, add BUFFER=ON to your MODE command: MODE COM1 XON=ON BUFFER=ON (for XON/XOFF software flow control) or: MODE COM1 RTS=HS OCTS=ON BUFFER=ON (for RTS/CTS hardware flow control) If you don't have a buffered UART, MS-DOS Kermit will lose characters galore at high transmission speeds. IDLE_SENSITIVITY should be set to 0 and IDLE_DETECTION_TIME should be 100 to reduce the jerkiness of DOS sessions. TCP/IP (and presumably other networks supported by MS-DOS Kermit) cannot be used with OS/2. OS/2's network interface is totally different from the methods (such as Packet Drivers) used by DOS. (You can, however, run MS-DOS Kermit over packet drivers, etc, if you boot a suitably-equipped DOS from your A: disk in a DOS window.) .