Display system and display apparatus

A display system, comprising:

• a portable device;
• a host;
• and
• a display apparatus, comprising:
• a USB (Universal Serial Bus) Type-C connector, connected to the apparatus and the portable device comprises an image-transmission channel and a data-transmission channel;
• a display panel;
• a multiplexing circuit, configured to separate the image-transmission channel from the data-transmission channel of the USB signal;
• a switch circuit, configured to control an operation mode of the multiplexing circuit;
• and
• a display controller, configured to control a display mode of the display panel;
• wherein in response to the display panel being in a first display mode, the display controller transmits a control signal to the switch circuit to control the multiplexing circuit to switch to a first operation mode,
• wherein in response to the multiplexing circuit being in the first operation mode, the portable device acts as a host terminal in the image-transmission channel, and acts as a device terminal in the data-transmission channel.