The invention refers to an exchangeable power-supplying unit (200, 300) arranged to supply electric power to a device (100, 400). The power-supplying unit (200, 300) is arranged so as to provide the device (100, 400) with one or several additional functionalities and it can preferably be attached so...http://www.google.de/patents/US7477923?utm_source=gb-gplus-sharePatent US7477923 - Exchangeable module for additional functionality
