Serial Cable ConnectionThis is the serial cable that I have used with the Parallella:
http://www.adafruit.com/products/954#Technical_DetailsConnect the white (RX) wire to the Parallella's TX pin
Connect the green (TX) wire to the Parallella's RX pin
Connect the black (GND) wire to the Parallella's GND pin
Do not connect the red power wire to the Parallella.
Connection to the Parallella is 115,200 bits per second, eight data bits, no parity, one stop bit (8N1)