[Nut-upsuser] Liebert UPS, serial cable questions

[George]

Hi,

I have a Liebert GXT2-1000RT230 UPS that is connected to my server
using a serial cable.

I have no idea to what port exactly it is connected so my first
question is: how do I find out what /dev/tty** should I use?

Do I need to install a device driver for it? Where do I find it?

What should I use and how do I do so the server shuts down if the
battery level is low?

Yes, I'm a newby, sorry.

Please help, thanks