Mobile terminal and method of indentifying SIM card thereof

A method of indentifying an operating voltage of a SIM card of a mobile terminal, comprising steps of:

• (a) presetting a plurality of different reference voltages to a power management module of a mobile terminal,
• (b) supplying a power supply of the lowest reference voltage of the plurality of reference voltages to the SIM card firstly,
• (c) when the mobile phone responds, determining whether the operating voltage of the SIM card equals to the present reference voltage, wherein when the operating voltage of the SIM card equals to the present reference voltage, the SIM card is successfully identified,
• (d) when the mobile phone does not respond, or the operating voltage of the SIM card does not equal to the present reference voltage, increasing the power supply to a reference voltage of the plurality of reference voltages higher than the present reference voltage to the SIM card, and proceeding step (c) and (d) repeatedly, and
• (e) when the mobile phone does not respond to the highest reference voltage of the plurality of reference voltages, prompting that the SIM card cannot be identified.