1. An electronic device, comprising:a priority port;
an initial port;
a system unit;
a linking control circuit coupled between the priority port, the initial port, and the system unit and adapted to normally connect a first linking path between the initial port and the system unit and disconnect a second linking path between the priority port and the system unit; and
a priority detection circuit coupled to the priority port and the linking control circuit to detect a connection state of the priority port, and configured such that upon detection that the priority port is connected to a first external device, the linking control circuit disconnects the first linking path and connects the second linking path;
wherein, when the second linking path is connected, the second linking path enables communication between the priority port and the first external device, and when the first linking path is connected and a second external device is connected to the initial port, the first linking path enables communication between the initial port and the second external device.