A closed container composed of a lid body and a lower container are provided in a cover body, and a supply pipe for nitrogen gas is connected to the cover body. The female connectors include, inter alia, a connector body that has an outer periphery and an aperture extending therethrough. When the gateway receives an inbound call from one of the mobile phones, or an outbound call from one or the telephones, the gateway applies routing rules to determine how to route the call. A residual vector of the redundant set is computed based on the system status.