Using linux as a serial console

[pstubbs@burpless ~]$ sudo cat /proc/tty/driver/serial
serinfo:1.0 driver revision:
0: uart:16550A port:000003F8 irq:4 tx:0 rx:0 CTS|DSR|CD
1: uart:unknown port:000002F8 irq:3
2: uart:unknown port:000003E8 irq:4
3: uart:unknown port:000002E8 irq:3
[pstubbs@burpless ~]$ cat /dev/ttyS0
cat: /dev/ttyS0: Permission denied
[pstubbs@burpless ~]$ sudo cat /dev/ttyS0

[pstubbs@burpless ~]$ sudo cu -l ttyS0 -9600
Connected.