Call receiving operation method of electronic system

An operation method of an electronic system, wherein the electronic system comprises an electronic device and an expansion device which is optionally electrically connected to the electronic device, the operation method of the electronic system comprising:

• when a first communication module of the electronic device receives a call signal, a controller of the electronic device detecting whether the expansion device is electrically connected to the electronic device;
• based on a result of the controller detecting whether the expansion device is electrically connected to the electronic device, determining whether the electronic system performs sound amplification with a first speaker of the electronic device or performs playing with a second speaker of the expansion device;
• when the controller detects that the expansion device is electrically connected to the electronic device, the electronic system performing sound amplification with the first speaker of the electronic device;
• when the controller detects that the expansion device is not electrically connected to the electronic device, the electronic system performing playing with the second speaker of the expansion device;
• when the controller detects that the expansion device is not electrically connected to the electronic device, the controller of the electronic device transmitting a signal to a second communication module of the electronic device so that the second communication module of the electronic device determines whether there is a wireless signal connection with a third communication module of the expansion device;
• when there is the wireless signal connection between the second communication module of the electronic device and the third communication module of the expansion device, the second communication module of the electronic device determining whether an answer signal sent by the third communication module of the expansion device is received;
• and
• when the second communication module of the electronic device receives the answer signal sent by the third communication module of the expansion device, the second communication module of the electronic device transmitting a voice signal to the expansion device,
• wherein in a step where the second communication module of the electronic device determines whether there is the wireless signal connection with the third communication module of the expansion device, when the second communication module of the electronic device determines that there is not the wireless signal connection with the third communication module of the expansion device, the electronic system performs a first mode of sound amplification with the electronic device.