I am looking to build a system that controls a relay based on input from this sensor. http://www.preconusa.com/humidity/HS-2000D%20Data%20Sheet.pdf
It is pretty old and it seems has been widely disregarded by the arduino hobbyist group. I haven't found any similar components mentioned as there is a new shielded sensor for much the same purpose. The data is output on pin 3 via rs-232 as it is microprocessor controlled; with the leads designed for rs232 input voltage. 
I know the leads on an arduino are much too hot for the sensor, I am not sure the safest way to wire this without causing stress on the components. As well it appears the component does not have a flat response and would need to be adjusted with some more complicated code.
Any help is appreciated. I am pretty green with this stuff.