Patent ID: 8060010

Claim:
A circuit, this circuit being provided for a communication partner appliance that is designed for contact less communication and as a data carrier, this communication partner appliance being provided for a communication system with at least one further communication partner appliance, in which circuit a first communication mode or a second communication mode can be activated, and which circuit has the means listed below: activators for activating the first communication mode or the second communication mode, and reception means for receiving a carrier signal that is transmitted by the at least one further communication partner appliance, and detectors for detecting the presence of the received carrier signal, these detectors transmitting within the circuit of the communication partner appliance a carrier signal present signal in the event that the carrier signal is present, and otherwise transmitting within the circuit of the communication partner appliance a carrier signal not-present signal as a consequence of a missing carrier signal, and command signal recognition means for recognizing a command signal that can be transmitted with the aid of the carrier signal, and wherein the command signal recognition means is further configured to subsequently generate and transmit within the circuit of the communication partner appliance a command-end signal that is separate from the transmitted command signal and represents the end of the transmitted command signal, and determination means for determining whether, after the occurrence of the command-end signal, at a given measurement point in time, the carrier signal present signal is present, with which determination means a first activation signal can be transmitted when the carrier signal present signal is present, and otherwise a second activation signal can be transmitted, with which first activation signal the circuit can be brought into the first communication mode with the aid of the activators, and with which second activation signal the circuit can be brought into the second communication mode with the aid of the activators.