Adapter and signal transmission method thereof

An adapter configured to transmit signal of a first electronic device to a second electronic device, the adapter comprising:

• a first universal serial bus (USB) type-C controller configured to electrically couple the first electronic device;
• a second USB type-C controller configured to electrically couple the second electronic device;
• and
• a plurality of USB type-C data transmission lanes connected between the second USB type-C controller and the first USB type-C controller;
• wherein the second USB type-C controller is configured to:
• (1) obtain a first transmission specification supported by the second electronic device;
• and (2) transmit the first transmission specification to the first USB type-C controller;
• wherein the first USB type-C controller transmits the first transmission specification to the first electronic device;
• the first electronic device transmits a control command to the first USB type-C controller according to the first transmission specification;
• the first USB type-C controller uses a corresponding number of data transmission lanes according to the control command;
• wherein the USB type-C data transmission lanes are traces.