Windows XP Pro SP3 latest patches
AV - McAffee
It seems that direct connect from WeatherLink 5.9.0 to the station also fails after a while with a 'Computer gave up waiting for a response from the station. Check port settings and connections."
This happens with or without the optoisolator installed. Without the optoisolator, I get a 112/114 mph wind reading due to a ground-loop … hence the need for the 9POP4 optoisolator 
I’m wondering if the datalogger in the VP could be failing somehow… it is 5 yrs old and has been in continuous service.
I’m lothe to just reset the datalogger (thereby causing a ‘hole’ in my WD data), but I’d appreciate any other guidance folks may have.