  Introduction
  ------------
  This sample Python application shows how to connect an Internet radio module
  to an echo server to send and receive data. In this example, data is sent to
  an echo server that echoes it back to be read by the module. The application
  will block during the transmission and read requests, but you will be
  notified if there is any error during the process.

  NOTE: This example uses the Cellular device (CellularDevice) class, but it
        can be applied to other Internet capable XBee device classes such as
        WiFiDevice.


  Requirements
  ------------
  To run this example you will need:
  
    * One Internet capable XBee radio (for example a Cellular radio) in API
      mode and its corresponding carrier board (XBIB or equivalent).
    * The XCTU application (available at www.digi.com/xctu).


  Compatible protocols
  --------------------
    * Cellular
    * Wi-Fi


  Example setup
  -------------
    1) Plug the Internet radio into the XBee adapter and connect it to your
       computer's USB or serial port.

    2) Ensure that the module is in API mode and connected to the Internet.
       For further information on how to perform this task, read the
       'Configuring Your XBee Modules' topic of the Getting Started guide.

    3) Set the port and baud rate of the XBee radio in the sample file.
       If you configured the module in the previous step with the XCTU, you
       will see the port number and baud rate in the 'Port' label of the device
       on the left view.

    4) Optionally, modify the text to be sent to the echo server changing the
       value of the 'TEXT' variable.


  Running the example
  -------------------
  First, build and launch the application. When the application starts, it
  connects to the echo server and sends the "Hello XBee!" message. To test
  the functionality, check that the following message (among others) is
  printed out in the console of the launched application:

    "Echo response received from 52.43.121.77:11001 >> '<TEXT>'"

   - Where <TEXT> is the text sent to the server and echoed back.

  That message indicates that the echo server echoed back the text sent and it
  was read by the Internet radio successfully.
