SunFounder 3in1 Kit - Page 348

SunFounder 3in1 Kit
3. Click on NEWLINE DROPDOWN BOX, select both NL & CR in the drop down option, enter AT, if it returns
OK, it means ESP8266 has successfully established connection with R3 board.
Now you can continue to follow 1.1 Configuring the ESP8266 to set the working mode and baud rate of the ESP8266
module.
344 Chapter 7. FAQ