It uses a single number of PIN! Autorecarga: it chooses from what balance you want that the charge of your card activates. When your balance arrives at that amount recharges the amount chosen by you.
It registers the telephone numbers from where you realize your calls and avoids to enter the PIN. Simply it dials to the number of access and the number of destiny.
Basic measurement to divide the duration of a telephone call. Example: in a card with rounding of 1 minute, a call of 1 minute 50 seconds will be received like 2 minutes.