Thank you for your inquiry.
Please, on Teltonika Configurator --> SMS / Call Settings (1st step) --> Authorized phone numbers (2nd step) set number which will be use for I/O event messages.
Then go to I/O settings (3rd step) and near parameters which events you want to get, please choose phone number (4th step).
After it, please do not forget to save changed settings to device.
Please let us know if you will have more questions for us.