I have a second home with a home automation system based upon a fast PC. For surveillance I use BI and I connect from outside using VPN and UI3, which is working very well. Although the house sits far out in the woods, it has the luxury of a fast fiber connection to the internet provider. The connection is not always reliable and occasionally I lose contact with the system, which may be particularly bad if we get a long corona lockdown in the fall, so I dream of establishing a backup internet connection using a cell service. It could also give me a reset option. The system has an ASUS router which can connect to a cell service using a special USB-stick, so it could be easy. Although that should work for outgoing connections, the cell service does not provide a public IP-number, so I wonder how I can connect to the ASUS router from outside?