Motherboard having two display connectors

A motherboard, comprising:

• a resistor;
• a display card controller;
• a first display connector comprising a first detecting pin connected to a power source through a resistor, wherein when an external display connector of a display device is connected to the first display connector, a grounded second detecting pin of the external display connector is connected to the first detecting pin, to make the first detecting pin grounded;
• a second display connector, wherein when the external display connector of the display device is connected to the second display connector, the first detecting pin of the first display connector receives a high level signal from the power source;
• and
• a signal switch chip connected between the display card controller, and each of the first display connector and the second display connector;
• wherein when the signal switch chip receives a low level signal from the first detecting pin of the first display connector, the signal switch chip outputs image signals received from the display card controller to the display device through the first display connector;
• when the signal switch chip receives a high level signal from the first detecting pin of the first display connector, the signal switch chip outputs the image signals received from the display card controller to the display device through the second display connector.