I have google then got this thread setserial
this thread relevant to other commands setpci lspci etc

if the hardware card is PCI in a PCI slot
I just know setpci command example was setpci -s 00:00.0 XX=YY

the hardware card is PCI and it need to link ln to /dev file like /dev/Stty0X

Do I need to setpci then setserial ? again, above setpci example ok?
I don't know example of command setserial

which distro?
what are you really trying to achieve? http://xyproblem.info/

fwiw, my machine has a setpci command, but not setserial.
setpci has a man page:

There is also the stty command.

As ondoho cites, it would be helpful to know what you're trying to do.

Noting that setting up a PCI interface is far different from setting serial interface attributes.

If I had to alter the PCI, I would do that action first.

Hello and welcome to LQ.

What exactly are you trying to do? Do you have a pci card serial board?

need to link ln to /dev file like /dev/ttySX

so I need to command(s)
setpci
setserial
ln


command stty ?
Ubuntu, Ubuntu had stty command inside?

This doesn't seem to make any sense.

"link ln" - as in Link using the ln(1) command? You need no form of setup for the serial device in order to create a soft or hard link.

However once again, what exactly are you trying to achieve? Besides the next one item you wish to do, instead we are asking for a full description of exactly what you need to do with the serial port so that we can advise you correctly and effectively.

Here is a reference for the stty(1) command.

I've used it from the command line, however from inside a C program there are different ways to configure a serial port.