The Calibration (CAL) processor applies electronics (ECA), PMT (PCA), and eventually optical (OCA) calibrations to the raw data held in the PMT, LG, OWL, BUTT, NECK and FECD banks, which have slots for both uncalibrated and calibrated data. The form of the calibrations is given in the chapters that describe the calibration processors. See ECA - 25.1, PCA -26.1 and OCA - 28.1.
The calibration processor has a number of switches to control the way calibration constants are applied. By default, the full official calibration is applied. For details of other possible modes see:-
The TCAL Bank
A couple of switches will be mentioned here.