Is there a DTU that supports SMS?

There are many such dtus. Sixin 4G DTU F2X 16 supports a variety of up-and-down trigger modes, including SMS, phone ringing and serial data triggering online and offline modes, which effectively reduces power consumption and avoids traffic waste. In the case of online wireless network signal or central network paralysis, it can automatically switch to GSM short message to send and receive data (data and short message communication are mutually backup and can be switched freely).