Attempts to send the SMS text message.
This function will return FALSE if the message has not been sent. This may be because the DroneCell is not plugged in, not powered on, or the SIM card is currently full.
Where DroneCell is the name you have given to the device in Project Designer.
If this function returns TRUE it doesn't mean that the text message has actually been sent yet - but rather that it has been queued up on the SIM card. Consequently it is guaranteed to be sent once the DroneCell gets a signal even if the DroneCell is turned off and back on in the meantime.