Connecting to UART

I have soldered a 1.8V FTDI cable to the IOT Expansion board of my Mango Yellow. I have connected the wires in this way:
Pin 4: Ground
Pin 12: RXD
Pin 13: TXD
Pin 14: CTS
Pin 15: RTS

Then I followed this tutorial: Octave Resource Protocol Guides. However, the demo code never gets a response from the board. It just keeps sending messages without getting a response.