Method and device checking the validity of a request to enable a function in a device

In a remote control (300) for defining the release request of a device (301) a carrier signal (T) available with a periodically changed frequency is modulated with a binary data signal and transferred from the remote control to the device. A received signal is compared for its signal frequency with the frequency of a receiving signal available in the device that changes its frequency opposite to the frequency of the carrier signal.