Attempts to place the DroneCell into a mode where you can send an SMS text message.
This function will return FALSE if the DroneCell is too busy doing something else, or TRUE if it is now ready for you to start entering the text body of your message.
When entering the text body of the message you can treat the DroneCell as an output stream and use the various print and '<<' functions to output the text.
Once your message has been created you must call sendSMS to try and send the text message.
Where DroneCell is the name you have given to the device in Project Designer.
The phone number you want to send the SMS message to.
The phone number is in the international format ie '+', country code ('1'=USA), followed by the rest of the number excluding any '0' prefix.
Note that if your code doesn't check the return value from this function then it will cause a compiler warning as it is 'unsafe' to continue trying to send a SMS text message if this function returns FALSE.