Redundant Communication for RTU

We want to design communication system for RTU in such a way that even if one source of communication is down, the data can be fetched through other communication media. One path will be primary and other path will be backup. But as the RTU communication port with SCADA is limited, is there any external reliable device where we can interface multiple type of communications (OFC/GPRS/VSAT) and in case of down of the primary communication then it will fall back to other communication available? Further the interface may be different (RS232/Ethernet) from communication provider but RTU port is on ethernet(RJ45).

More idea on redundant communication from others is welcome.