We expose the serial ports as device files that you can open and provide a subset of the termios() API to allow configuration. Full details of port naming and supported APIs are available in the Digi Python Programmer's Guide, on the CD or available from our support pages at http://ftp1.digi.com/support/documentation/90000833_b.pdf.
However, a quick summary:
* The serial port is named '/com/0'.
* Devices are managed through the os file routines, not the Python file objects
So, you would start by opening the port:
serialfd = os.open('/com/0', os.RDWR)
data = os.read(serialfd, 512)
If you have configured the serial port correctly from the Digi UIs, you can immediately perform reads, writes, and selects with the fd. Otherwise, you can use the termios API to configure the port before data transfer.