For many years I have used a mobile broadband dongle for internet access when travelling (and no ready free wifi). Usually one just gets a pre-paid data SIM from a telco, plug the USB device into the computer and away we go ... and the data count grinds its way down with usage.
What I'd like to know is, what happens if the same SIM is put into a smart 'phone, which in turn is tethered to the computer (via USB cable).
Does the 'phone merely act just like the modem/dongle, or does being in a 'phone invoke different charges because the telco's system now thinks its making voice calls as well as data?