Remote control system for motor vehicle related devices

Process for operating a remote control device having a portable remote control unit, at least one function unit controlled by way of the remote control unit, and a bidirectional data communication link which transmits coded data between the remote control unit and the function unit, said coded data being generated by a symmetrical coding method, said process comprising steps for usage-authorizing, outside-usage-protected, assignment of a particular portable remote control unit to a particular function unit to be controlled by the particular portable remote control unit, by means of the assignment of a common secret coding information of a symmetrical coding method used for the authentication, comprising:

• activating a learn mode in the function unit and in the remote control unit, and transmitting a learn-mode reporting signal from the remote control unit to the function unit;
• sending a learn mode acknowledgment signal from the function unit to the remote control unit upon receipt of the learn mode reporting signal;
• calculating new secret coding information by means of a coding algorithm of the symmetrical coding method as a function of a basis secret coding information and of derived secret coding information previously stored in the remote control unit, and transmitting said new secret coding information to the function unit upon receipt of the learn mode acknowledgment signal by the remote control unit;
• replacing the previous secret coding information with the received, new secret coding information in the function unit, said function unit sending an acknowledgment signal;
• and
• replacing the derived secret coding information previously stored in the remote control unit with the new secret coding information in the remote control unit upon receipt of the acknowledgment signal.