COBHAM Satcom EXPLORER 540 User & Integrator's Manual page 125

If the cellular connection fails in Cellular modem preferred mode or External
modem preferred mode
Important
Note
If the EXPLORER 540 detects that the cellular connection is failing, it will switch the
traffic to the BGAN connection, which now becomes the Network in use.
After a switch to the BGAN backup connection the EXPLORER 540 will try to recover the
Cellular data connection. If the Cellular data connection is successfully re-established,
the EXPLORER 540 will start to monitor and validate the Cellular connection. The
EXPLORER 540 will now prepare a switch back to the Cellular connection but will
monitor the traffic volume in order to avoid switching while traffic volume is high. The
EXPLORER 540 will monitor the traffic volume at regular intervals in order to switch
back to the Cellular connection. If the traffic volume remains high the EXPLORER 540
will eventually switch back to the Cellular connection after 30 min.
If recovery of the Cellular data connection continues to fail, the EXPLORER 540 will
continue to use the BGAN connection as Network in use (while still trying to reestablish
the cellular connection) until the EXPLORER 540 is restarted or the BGAN connection
fails.
If the BGAN connection fails while it is Network in use or if the backup BGAN
connection is down or fails when the EXPLORER 540 attempts to switch to the backup
BGAN connection, the EXPLORER 540 will reboot in order to attempt to recover both
the Cellular and BGAN connections.
If the BGAN connection fails while it is operating as standby connection, the
EXPLORER 540 will try to re-establish the BGAN connection without rebooting the
terminal.
98-148232-K
In External modem preferred mode, if you are not using the Connection
watchdog nor PRISM, the terminal will not be able to detect if the
cellular connection fails, and consequently will not switch over to BGAN
backup.
After terminal start-up or initial activation of Cellular modem preferred mode,
the EXPLORER 540 will allow the Cellular connection a period of 3 min. to
become operational before it is considered failing and the EXPLORER 540
switches to the BGAN connection.
Chapter 4: Configuration with web interface
PRISM/WAN switching
4-61