Identification signal registering method and apparatus

An identification signal registering method of registering an identification signal used for a detecting apparatus to identify an apparatus (1) to be detected, includes a step of transmitting a communication request signal from a remote control apparatus having an inherent identification signal to the detecting apparatus (10), a step of receiving the communication request signal by the detecting apparatus and transmitting a random number signal therefrom to the remote control apparatus, a step of receiving the random number signal by the remote control apparatus and encrypting the inherent identification signal by using the random number signal to transmit it therefrom to the detecting apparatus (10), a step of receiving and decrypting the encrypted inherent identification signal by the detecting apparatus, a step of, if the decrypted inherent identification signal coincides with an identification signal previously stored in the detecting apparatus, setting the detecting apparatus in its mode for registering an identification signal of the apparatus to be detected, and a step of, in the registration mode, transmitting the identification signal from the apparatus to be detected to the detecting apparatus (10) to register this identification signal in the detecting apparatus.