http://www.esp8266.com/wiki/doku.php seems to be a good starting place with a lot of interesting information. Also very extensive documentation can be found in Neil Kolban’s ESP8266 Book (pretty large PDF).

USB->Serial Converter:

  • red: +5V ?
  • black: GND
  • white: TXD 3.3V
  • green: RXD
  • yellow:



Attention: The breakout boards I got came with an unmounted voltage regulator IC. I had to remove the resistor bridge in order to use the regulator.

Connection of the serial cable to the breakoutboard:


  • red -> VCC
  • black -> GND
  • white -> RXD (!)
  • green -> TXD

Plugging the converter into the USB plug at the PC.


shows that the converter is detected.

minicom -D /dev/ttyUSB0

With baudrate 115200 I can issue AT commands after terminating them with CTRL-M CTRL-J and get the proper response.
At least in Minicom CTRL-M can be replaced by the RETURN key.
The commands need to be in upper case.

I will quit the step “connecting to my wifi” and continue directly with “uploading new firmware”.