The AP9335T is designed to connect to APC UPSes or NetBotz boxes to provide a temperature reading. I was hoping to see an IC inside the one I opened up, but its just a thermistor. It reads 9.8k Ohms at about room temperature, and resistance decreases as temperature increases. At body temperature it reads 6.9k. Pressed against an ice cube it reads 20k. Based on this, the thermistor seems to be a 2700k type.
|1||Vcc||Vcc for Type Sense|
|3||Type Sense||Connected to Vcc via 0 to 0.4kOhm resistor|
A 10K Thermistor may be used. Thermistor seems to be B0/50 K=3970
There is also an AP9335TH.
It contains a temp-sensor and a humidity-sensor. Pin 1-3 should then have a 1k2 resistor. Position of the pins for humidity sensor is unknown.