Add new ports. devel/pyvisa:
Python bindings to the "Virtual Instrument Software Architecture"
VISA library, in order to control measurement devices via GPIB,
RS232, or USB.
WWW: https://pypi.python.org/pypi/PyVISA
devel/pyvisa-py:
PyVISA-py is a backend for PyVISA. It implements most of the methods
for Message Based communication (Serial/USB/GPIB/Ethernet) using
Python and some cross platform libraries.