pyserial and port names?

I am trying to make pyobd work on my Leopard notebook, using a U232-P9
USB-Serial adapter and pyserial.

pyobd selects the ports unnamed as 'COMM1' 'COMM2' etc.
Yet when resetting the interface, I get a message that opening the
port /dev/cuad0 (for COMM1) failed: ENOFILE.

And true enough, there is no device /dev/cua* at all.
I do see a device /dev/ttys00 /dev/ttys01 etc

Should I just mknod /dev/cuad0 with the same major/minor numberes
as ttys00 and so on?

I am also unsure which port my USB Serial adapter really provides, as I
cannot find any message on it in /var/log announcing the availability
of a new port (or that the device is even detected).
The system profiler does list it when it is plugged in, but does not
say anything about the device that it provides. Is there any way I
find that out?

thanks
M