Thanks everyone. I used the site from submix8c and found this diagram. My usb cable only has pins up to pin 8. According to this it looks like I need 9 and 10 which seems strange. I guess I need a different cable.
Pin 9 is "KEY" i.e. it is not connected and used to identify the pins layout.
A single USB port has 4 (four) pins (just as a USB cable has four wires):
- USB Power +5V
- USB Data -
- USB Data +
- USB Ground (0V)
See also (beware, the pin numbers are different, but the concept is the same):