A method and system for connecting signal paths in a circuit arrangement with multiband capability for processing and/or influencing signals in radio communication, on the basis of which at least the transmission paths of a corresponding circuit arrangement are activated or deactivated on the basis of the presence of a transmitted signal from a terminal which is operated with the circuit arrangement. The transmission paths, which are deactivated in a basic state of the circuit arrangement, are periodically checked in succession for the presence of a transmitted signal from the terminal with a multiplexer that forms a functional component of a detection unit and that is switched through by a controller for sequential scanning of the transmission paths for the presence of such a transmitted signal. If a signal is present, only a transmission path for the correct frequency band of the transmitted signal is activated and continuously checked for the presence of a transmitted signal.