Abstract: Given a device for contact-free position measurement, a movable or resting part that represents a load in an alternating field or that is designed as an element emitting field lines is spatially neighbored by a sensor carrier that exhibits a plurality of individual sensors that are electrically and spatially separated from one another, whereby each of said individual sensors can be applied to direct or alternating voltage, and whereby an interrogation and evaluation means is provided, to which each of the individual sensors is connectable for the purpose of identifying its output signal that is dependent on the position of the positionally variable or resting position indicator.

Abstract: An apparatus for mutual information transmission between an electronic lock and a key uses antenna coils at both the key and lock. A periodic signal is emitted from the lock and is received by the key upon activation of a key electronics and emission of a coded information signal. This returned signal received from the lock coil is briefly short-circuited or damped at the key side in order to produce a synchronization switch synchronizing the points in time of the signal appearance. Electronic converters are provided which, given the pre-condition that the short-circuit signal extends over a plurality of signal pulses, generate a digital signal corresponding to the short-circuit times.

Abstract: Device for identifying an information, particularly of an access control consisting of electronic lock and key part, wherein given approach of the key part toward the lock part, its oscillator part oscillates at a high frequency, the oscillation is picked up by the key part and, modulated with a frequency or pulse pattern serving as a key identifier, is transmitted back to the lock part and is further processed by the reception and recognition means at the lock side. The reciprocating transmission of the energy between the lock and key part is carried out by a wave coupling by means of antenna coils whereby an inductively coupled synchronization switch is produced in that an altered signal curve is produced at a first coil at the lock side, being produced, for example, by means of a more or less complete short at a second coil at the key side or by means of impressing energy on the second coil.