Vaisala 425A Anemometers
These measure wind speed and direction by timing ultrasonic pulses between the three transducers. I got three off ebay in unknown condition but have had good luck getting them going again.
Firmware
There are several versions of firmware, I have 2.03, 5.10, and 6.01
Thus far only 6.01 actually behaves as the manual describes. 2.03 and 5.01 do not appear to have the configuration menu, so I am not sure how you configure the units, sampling rate, etc in that case.
I have the configuration jumper setup for the RS232 connection. Something to be aware of is the command buffer is flushed every 20ms so some commands cannot be typed in by hand - paste the whole command into the console for testing. Obviously this isn't a problem once you hook it to something automated.
Connectors
There is a single Amphenol connector, AMP 206037-1. The pins to order are TE Connectivity 66101-2.