The present invention discloses a multi-terminal positioning method, and a related device and system. The docking tray is also serves as a compact and light-weight auxiliary power source for the portable computer that may be transported with the portable computer. Connected to the reception aerial is a signal detector which has a reaction threshold level that can be toggled between a high value and a low value. A trash compactor has a trash compressing member pivotably disposed via a shaft 154 on a frame. 2 mlg of treated powder and a contact angle of water with the treated powder is at least 100.