You hang up to avoid a Belgacom charge, and the computer calls you back, providing you with a stateside dial tone so you can dial as if you were in the United States.
The computer that calls you back is using the internet to provide you with a dial tone.
mnli hypothesis: The computer that calls you back is using the internet to provide you with a dial tone. premise: You hang up to avoid a Belgacom charge, and the computer calls you back, providing you with a stateside dial tone so you can dial as if you were in the United States.