Part 1 answered:
Looking in /var/log/messages for a FTDI,USB or UART shows
Dec 13 00:30:18 badgergateway /kernel: ucom0: FTDI FT232R USB UART, rev 2.00/6.00, addr 4
From the cli, cat /dev/cuaU0 opens the serial port and shows me a stream of incoming serial data at 9.6kbps (It may be possible to negotiate higher since the UART is capable of this). I am reading input data from an Arduino USB port.
Part 2 testing to follow.