There are the 4 serial devices corresponding to COM1 - COM4:
/dev/cua0, /dev/ttyS0 (COM1) address 0x3f8 IRQ 4
/dev/cua1, /dev/ttyS1 (COM2) address 0x2f8 IRQ 3
/dev/cua2, /dev/ttyS2 (COM3) address 0x3e8 IRQ 4
/dev/cua3, /dev/ttyS3 (COM4) address 0x2e8 IRQ 3
The /dev/ttySN devices are for incoming connections and
/dev/cuaN devices for outgoing connections.
N is the serial port
number. In this document, I refer to COM1 as ttyS0, COM2
as ttyS1, COM3 as ttyS2, and COM4 as ttyS3. If I am
referring to a specific device in /dev, I will always
prepend /dev to avoid confusing you.
On some installations, two extra devices will be created,
/dev/modem for your modem and /dev/mouse for your
mouse. Both of these are symbolic links to the appropriate
/dev/cuaN device which you specified during the
installation
(unless you have a bus mouse, then /dev/mouse will point to
the bus mouse device).
There has been some discussion on the merits of /dev/mouse and
/dev/modem. I strongly discourage the use of these links.
In particular, if you are planning on using your modem for dialin
you will run into problems because the lock files will not work
correctly if you use /dev/modem. Use them if you like, but
be sure they point to the right device.
/dev
/dev/ttyS0 major 4, minor 64 /dev/cua0 major 5, minor 64
/dev/ttyS1 major 4, minor 65 /dev/cua1 major 5, minor 65
/dev/ttyS2 major 4, minor 66 /dev/cua2 major 5, minor 66
/dev/ttyS3 major 4, minor 67 /dev/cua3 major 5, minor 67
Note that all distributions should come with these devices already made correctly.
/devIf you don't have a device, you will have to create it with the
mknod command.
Example, suppose you needed to create devices for ttyS0:
linux# mknod -m 666 /dev/cua0 c 5 64
linux# mknod -m 666 /dev/ttyS0 c 4 64
You can also get the MAKEDEV script, available on the usual
FTP sites. This simplifies the making of devices. For example,
if you needed to make the devices for ttyS0 you would
type:
linux# cd /dev
linux# MAKEDEV ttyS0
This handles the devices creation for the incoming and outgoing devices.
The devices your multiport board uses depends on what kind of board
you have. These are listed in detail in the
rc.serial which
comes with the setserial program. You will probably need to
create these devices. Either use the mknod command, or get the
MAKEDEV script. Devices for multiport boards are made by adding
``64 + the port number''. So, if you wanted to create devices for
ttyS17, you would type:
linux# mknod -m 666 /dev/cua17 c 5 81
linux# mknod -m 666 /dev/ttyS17 c 4 81
Note that ``64 + 17 = 81''. Using the MAKEDEV script, you would
type:
linux# cd /dev
linux# MAKEDEV ttyS17