There are
many types of phone cards available to those who travel abroad and require keeping
communication with the world they are leaving behind. Among these, the stored
value cards are so called because the cards contain stored balance that is
available to you as you use the card. The public payphone booth machines read
the balance available with the card. The phone reads it as you insert the
calling cards in the phone machine’s card reader. It is normal for you to draw
an analogy with a banks’ automated teller machine, as it is almost similar to a
phone’s card reader.