SMS Function  
This  function  allows  users  to  remotely  retrieve  modem’s  signal  strength,  WAN  IP  address, 
remotely reboot the modem, change APN and configure WAN username and password via SMS. 
This function is enabled by default. Phone number added to the below list can only send SMS to 
the modem. If no phone number is configured, modem accepts message from any phone number 
and  process  it  accordingly.  Modem  will  send  acknowledgement  of  SMS  message.  The  phone 
numbers must be in International format only.