Abstract: For the control of the drive slip of a motor vehicle a first rotation rate sensor produces a first rotation rate signal corresponding to the rotation rate of the driven wheel or the output rotation rate of the change-speed gear. A second rotation rate sensor generates a second rotation rate signal corresponding to the rotation rate of a non-driven wheel. The friction clutch of the motor vehicle is engageable and disengageable through a controllable servo drive, and a control system controls the clutch in the release direction when the first rotation rate signal represents a rotation rate higher by at least a pre-determined difference value than the second rotation rate signal. The control system controls the clutch in the engagement direction when the rotation rates represented by the first and the second rotation rate signals differ by less than the pre-determined difference value.

Abstract: For controlling a central locking installation and/or theft alarm of a motor vehicle a switch lock installation is provided which comprises at least one lock with mechanical tumblers for the mechanical locking and unlocking of a door or a bonnet of the motor vehicle. The tumblers form a first key secret. The key which blocks the tumblers carries an electrically, magnetically or optically readable information carrier for a second, operationally variable key secret. A reading device detects the information of the second key secret in a position in which the mechanical tumblers of the lock are released. If the key is moved in the opening direction of the lock, a control circuit compares the information read by the reading device with an ideal information stored in a memory circuit and controls the central locking installation and/or theft alarm accordingly.