Mobile phone and method for selecting a SIM card

1. A mobile phone, comprising:

at least two subscriber identity module (SIM) cards;

at least one processor;

a storage system to store a plurality of history telecom operators of history outgoing numbers that are queried from a number portability database (NPDB), and one or more programs that are executed by the at least one processor, the one or more programs comprising:

a querying module operable to query the NPDB for at least two telecom operators of the at least two SIM cards, and determine whether a telecom operator of an outgoing number dialed using the mobile phone is found in the storage system, and whether a validity period of the telecom operator of the outgoing number in the storage system expires when the telecom operator of the outgoing number is found in the storage system, obtain the telecom operator of the outgoing number from the storage system when the validity period does not expire, and query the NPDB for the telecom operator of the outgoing number when the validity period expires; and

a selecting module operable to select one SIM card with one telecom operator same as the telecom operator of the outgoing number from the at least two SIM cards.

2. The mobile phone of claim 1 , wherein the selecting module is further operable to set one of the at least two SIM cards as a default SIM card.

3. The mobile phone of claim 2 , wherein the selecting module is further operable to determine whether the telecom operator of the outgoing number is the same as the telecom operator of any one of the at least two SIM cards, select one SIM card to dial out the outgoing number upon the condition that the telecom operator of the outgoing number is the same as the telecom operator of the one SIM card, and select the default SIM card to dial out the outgoing number upon the condition that the telecom operator of the outgoing number is different from the telecom operator of any one of the at least two SIM cards.

4. A method for selecting a subscriber identity module (SIM) card of a mobile phone comprising at least two subscriber identity module (SIM) cards, the method comprising:

providing a plurality of history telecom operators of history outgoing numbers that are queried from a number portability database (NPDB);

querying the NPDB for at least two telecom operators of the at least two SIM cards;

receiving an outgoing number inputted by a user;

determining whether a telecom operator of the outgoing number is found in a storage system of the mobile device;

determining whether a validity period of the telecom operator of the outgoing number in the storage system expires; if the telecom operator of the outgoing number is found in the storage system,

obtaining the telecom operator of the outgoing number from the storage system if the validity period does not expire; and

querying the NPDB for the telecom operator of the outgoing number if the validity period expires; and

selecting one SIM card with one telecom operator same as the telecom operator of the outgoing number from the at least two SIM cards.

5. The method of claim 4 , further comprising: setting one of the at least two SIM cards as a default SIM card.

6. The method of claim 5 , further comprising:

determining whether the telecom operator of the outgoing number is the same as the telecom operator of any one of the at least two SIM cards;

selecting one SIM card to dial out the outgoing number if the telecom operator of the outgoing number is the same as the telecom operator of the one SIM card; and

selecting the default SIM card to dial out the outgoing number if the telecom operator of the outgoing number is different from the telecom operator of any one of the at least two SIM cards.