The main card and payment of the operator can be recharged, because the main and secondary card is the same account, the charge after recharging is placed in the same account, and the main and secondary cards can use the call fee inside. When the operator deduces the monthly rent, the mobile phone number displayed on the account is the main card number, and the call fee of the secondary card is used as a part of the main card. Two cards, one card can be charged, and each card can be charged with two cards, both can make phone calls.