between callback service and travel calling card
Travel card works
better if you travel overseas and you:
a) stay for a very
short period of time;
b) do not have a phone line to stay with or have a mobile phone to
c) change locations all the time.
Callback works better
when you are in a foreign country and you:
a) stay for a longer
period of time;
b) have a stable place to live either in a hotel or a guest
c) have a fixed or mobile phone with you.
d) are in a country where calling card is not able to serve.