>Let's backup a moment. Is immediate transmission needed? The 21st century way is to queue the data and send when the Internet comes back online.
>
>Like a mobile app ought to, you mean? ;-)
>
>In this case there's a customer at the counter and everybody needs to know whether an insurer is going to cover any of the cost. The modem is a fall-back option in case the internet is down. I know this sort of question is neatly sidestepped in the whole Azure/Cloud etc theorizing, but to this day sometimes a donkey is better than an automobile.

Agreed. It's bad enough that you can have local internet failure, but when you talk medical needs you need to look at other possibilities like disaster communications or massive internet outage (cyberwarfare, etc).

Phones may still work in these cases (although cyberwarfare has the possibility of taking out phone carriers as well).

Aside from courier, radio, or carrier pidgeon, phone/modem is a viable option.