| 摘要 |
A building monitoring system having dual communication options is disclosed. The controller is configured to communicate via a pair of communication networks, According to one embodiment of the invention, the controller is connected to a Public Switched Telephone Network (PSTN) and to a Global System for Mobile Communications (GSM) network. The controller further includes a gateway to selectively connect the PSTN to the GSM network. The controller may monitor the status of the PSTN line. If the PSTN line is operational, the gateway connects the PSTN jack from the telephone to the PSTN jack for the telephone line. If the PSTN line is not operational, the PSTN jack from the telephone is connected to a converter which is, in turn, connected to a cellular radio. The converter is configured to convert the analog signals for the PSTN to digital signals for transmission via the GSM network and vice versa. |
