Transmission system and related transmission method

A transmission system and a related transmission method are provided. The transmission system includes a transmission interface and a transmission apparatus. The transmission interface attached to a user device has a set of charging pads coupled to charging pins of the user device. The transmission apparatus includes contact circuits, a detection circuit and a control circuit. In a scanning period, the control circuit sequentially provides an enablement voltage to a first scan terminal and a second scan terminal of each of the contact circuits, and further records the contact circuit which outputs a detection signal with a first level. When the number of the recorded contact circuits is higher than a setting value, the control circuit analyzes the corresponding positions of the recorded contact circuits, so as to switch to an operation period and to provide power through contact pairs of the contact circuits covered by the charging pads.