A thermistor is a resistor that varies its resistance with the temperature. There are two main types; those that increase resistance when the temperature rises (PTC), and those that decrease resistance the temperature rises (NTC).
Thermistors are typically suitable for moderate temperatures, like outdoor/indoor applications.
Thermistors are usually defined by their resistance at 25°C and a B-parameter. These two parameters can be used to convert the resistance to an actual temperature. However the relationship between temperature and resistance is not linear and the math required (the Steinhart-Hart equation) to do the conversion is not completely trivial.
The ezeio can be programmed to convert thermistor resistance to temperature. Scripting is required. eze System provides this as a standard support service. Supported 3rd party expansion modules for the ezeio have the conversion math built-in.