Rudi Ahlers wrote: > That was a typo in my first post. I am using /dev/ttyS0 - with a bit S :) > > I have also noticed that there's no tty* in "dmesg | grep tty" or grep > tty /var/log/demsg > > could this be the problem / reason? I'm running CentOS 5.1 x64 with > Xen 3.0 kernel hmmm. 5.1 i686 w/o xen... $ grep tty /var/log/dmesg serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A 00:0b: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A 00:0c: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A $ sudo setserial /dev/ttyS0 /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4 $ sudo setserial /dev/ttyS1 /dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3 (old school pentium-III 800 on a i815 board)