Bausch Datacom DinBox RTU M4 Reference Manual page 22

Watchdog functions
• Connection Teardown Timeout
If, for whatever reason, the IEC60870-5-104 master connection is lost
during more then x minutes the WAN module will restart it's GPRS/IP
stack/TCP server to be sure that the RTU isn't disconnected and not
listening to port 2404.
• Periodical reset
The RTU will completely reset after this timeout if no TCP connection is
detected.
•
Periodical Ping Host
If the basic router function is used, the connection can be tested by a
periodical ping. GSM module will reset after (3) failed pings.
•
Periodical Ping Interval
Interval for the periodical pings.