A device for interconnecting a first communication network and a second communication network comprises a plurality of components functioning in an active mode or a standby mode. Said interconnection device performs the following steps: changing to active mode (401) the plurality of components under the control of a secondary processor, the secondary processor being a component of the interconnection device continuously in active mode and controlling changes to active mode following the change to active mode, sending (405) an interrogation request to a service-management server (110) connected to the first communication network in order to check the existence of service demands, receiving (407) a response to the interrogation request; and changing the plurality of components to standby mode (427) at an instant dependent on the response received.