Olivetti PR4 SR Service Manual page 77

Calibration is performed by carrying out the second part of the calibration procedure FIVE TIMES. The operator
must therefore insert the check five times.
Upon completion the outcome of the calibration procedure will be printed:
OK Calibration Ok
A/D saturation
Too many peaks Too many peaks (noise)
Verify head Verify head connection (inverted)
Not OK
XYAA6336 Service Manual 6-13