Looking for serial/parallel I/O libraries for Python

[dk-info]

I wish to develop interactive testing software using Python, and the
instruments often have only a serial or parallel port. I have not been
successful using a USB-> serial converter as the flow control
protocols are not deterministic, and I loose data.

Are there any packages out there that have this interface for XP/Vista/
7?

Thanks in advance for any help you can proffer.

David W,

Melbourne