96Boards Nitrogen - No USB Serial Port


I am having a small challenge with my Nitrogen board. When I plig the board in the MBed disk drive shows up, and I can drag and drop proigrams, or run gdb with no problems. However the second Serial Device (COM3xx) is not visible. When I plug in a Freescale Freedom board, or a STM32F4xx board the Mbed and serial devices show up, but no serial device when I plug in the Nitrogen board.

I have checked that the serial signals from the nrf51 do connect to the debug micro-controller, but they don’t seem to be available over the USB connection.

How do I access the COM port? Do I need to use a USB-Serial adapter and connect to the actual serial connectors on the Nitrogen board?