Display system and power-saving method thereof

A display system, comprising:

• a first display device, comprising an illumination module, a signal input port, a signal output port, and a control circuit, wherein the first display device is adapted to switch between a normal operation mode, a first standby mode, and a second standby mode;
• wherein
• the illumination module provides an illumination beam in the normal operation mode, and does not provide the illumination beam in the first standby mode and the second standby mode,
• the signal input port has a preset pin, in the first standby mode, the signal input port and the signal output port are disabled, and in the second standby mode, the signal input port and the signal output port are enabled,
• the control circuit is coupled to the illumination module, the signal input port, and the signal output port,
• wherein in the first standby mode, the control circuit detects whether the preset pin of the signal input port generates a voltage variation or maintains at a preset voltage value during a preset period,
• when the control circuit detects the voltage variation or the preset voltage value, the control circuit switches the first display device from the first standby mode to the second standby mode, and generates an output signal according to an input signal received by the signal input port and allows the output signal to be transmitted to the signal output port, or establishes a network connection of the first display device according to the input signal received by the signal input port,
• when the control circuit does not detect the voltage variation nor the preset voltage value, the first standby mode is maintained by the control circuit, wherein both the voltage variation and the preset voltage value are greater than 0.