摘要 |
A random number and a user-specific identifier are coded (14) in a transmitter (1) and transmitted to a receiver (2). Here the received signal is decoded (22), separated into its basic components and coded anew (23). If the generated signal and the received signal correspond (24), the transmitter (1) is therefore accepted as legitimate. Thereupon, a release signal is relayed to a departure blocking device or a control signal to a control device. With this device no initialization by the user and no rewritable memory is necessary. <IMAGE> |