No, that works only if the database of POS system is in the cloud or accessible from the outside world, not if it is on some local server like it is now.
I have a restaurant and we work with a Point of Sale software on iPad that allows us to take the orders of the customers.
All the iPads are running on the app and connected to the same local network (connected to internet). On this network, there are also some network printer that are used to print the orders in the kitchen / bar. We have also a terrace where we serves the customers from outside the restaurant. The issue is that we cannot catch the Wifi network and it’s impossible to add a antenna or a Wifi router to extend the Wifi range.
We are thinking about getting Cellular iPad to take orders from outside.
In that sense, my question is to know if it is possible to access to a local network (which gives access to internet) through a VPN with the Cellular network of the iPad (4G).