Did some quick search and from this link it looks like its rs-232. so you will need a serial cable or usb cable connected to the gateway, unless you have bought a network interface card that supports modbus tcp. If there is no serial port the usb might show up as a serial port.
Also inside the ignition exchange project, in the others folder, is a readme_install_text file with a lot information about the different configurations around the ups itself and what is needed.