Thanks for the response but it hasn’t really answered my question. I’ll explain it better.
My primary sim is data only(no voice or sms capability) Optus is the carrier. I have a secondary sim which is used for back up only it has data (limited voice and sms) Telstra is the carrier. I have it set to switch from primary to secondary when there’s a fault as in the carrier has a fault. I would like the secondary sim to send me an sms to alert me that I am now running on secondary sim. I have the teltonika checking signal/ data to switch back if primary sim is available again.
Hope I have explained this a little better this time.