A card reading device includes a multi-functional connector capable of connecting to one of a variety of portable electronic devices and a control circuit of the card reading device respectively, wherein the control circuit has a detection circuit. Once a portable electronic device is connected to the cad reading device, the detection circuit is automatically activated to detect an identification (ID) of the electronic device. In response, one of second drivers is activated to drive the electronic device for electrically connecting the electronic device and reading data from the memory cards connected thereto.