The m100 can operate at 19200 bps but the screen can only scroll fast enough to accommodate 600 baud.
So for higher speeds you need to use flow control and/or a data transfer mechanism that does not use the screen. Also on Linux I've had very little luck with software flow control so I wrote HTERM which implements hardware flow control. I've used it successfully at highest baud rate 76800 bps. -- John.
