Using "Execute command", you can start a script that will send SMS to multiple numbers when backup WAN will be enabled.
I tried creating a little script and it was working fine.
You can also try it, maybe it will be suitable for your solution.
To begin with, connect to router via SSH (you can use CLI feature (Services → CLI)).
Then execute following command:
It will create a new file in /etc/init.d directory and allow you to edit the file:
Paste following text to the file:
# Example script
gsmctl -S -s "0037060000000 MobileWAN"
gsmctl -S -s "0037060000001 MobileWAN"
gsmctl -S -s "0037060000002 MobileWAN"
To save changes, press the "Escape" ("Esc"), type :x and press "Enter".
Then execute CLI command:
chmod +x /etc/init.d/example
After that you will have a script that could send messages to three selected numbers after the backup WAN.
To start script use command:
You can change the script by adding more numbers and changing the message text.
More information regarding the scripts can be found here
Finally enter command:
To "Execute command" field.