Sparkfun FTDI Basic Breakout Board (3.3V) which works out-of-the-box in Linux and Windows. No extra drivers needed.
The green wire is connected to the RX-Receive on the FTDI board
The yellow wire is connected to the TX-Transmit on the FTDI board
The blue wire is connected to the GND-ground on the FTDI board
The RX and TX pads are really close to each other, so soldering needs to be done carefully!
The GND pad can be found on the other side of the PCB, above the RK3188 CPU
Overview of the end result with the RX and TX connected at one side of the board (first picture) and the GND on the other side (second picture)