What is the difference between gas calibration and the user-calibration mechanism (CAL option) offered as an option?

The 3-point calibration mechanism is a process used to adjust real channels other than gas channels. This mechanism is reversible in that, once calibration is complete, it is possible to disable it or delete the entered points in order to restore the product to its initial state. This mechanism applies to real channels such as temperature, relative humidity, atmospheric pressure, etc.

For CO₂ channels, the calibration performed (which is supported by default by all CO₂ sensors without the purchase of an additional option) is a one-point instant calibration that is irreversible, in the sense that the only way to delete a calibration is to perform a new one to overwrite the previously entered point.