Re: How to use serial ports?

[Tapio Lehtonen <tapio.lehtonen@dnainternet.net>]

Did not check BIOS for port settings, I supposed ports are enabled since 
dmesg and setserial show the port.

root@phb:~# dmesg | grep -i tty
[    0.000000] console [tty0] enabled
[    1.072850] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[    1.073628] 00:0a: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
root@phb:~# setserial -g /dev/ttyS*
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
/dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
/dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4
/dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3
root@phb:~#

The computer has two serial ports, so I am a bit worried that only one 
shows in the above. Maybe the other is disabled in BIOS. I'll check next 
time I boot.

No breakout box or any such fancy stuff. The null modem cables I used 
did work last time I used them, if find it unlikely all of them would 
have broken when unused in the cupboard.

I tried both with and without RTS/CTS.

I added the user to group dialout, so the user can read and write to the 
/dev/ttyS0 device.


   Tapio Lehtonen