A method and a system transmit data between a technical apparatus which has a reception unit, a transmission unit and a computer unit, an external device which has a reception unit, a transmission unit and a computer unit, and a mobile terminal which has a reception unit, a transmission unit and a memory unit. The method and system allow registered, authenticated users to use the mobile terminal to perform safe reservation or enabling for a technical apparatus, without requiring an online connection and check between the technical apparatus and the external device for the purpose of authorization and authentication of the user.