So, you assign values to very specific states of matter and call those the reference points for your temperature. For instance, freezing of water or boiling of water, the standard ones.

The parts have a standard voltage input, which together with the differential reference input allows easy interface to an external temperature sensor, such as an RTD, thermistor, or diode.

This speciality standard will give a go-ahead for using as the reference of the cold and room-temperature microwave noise standard source below 3dB ultra-low-noise received system.