Covidien Nellcor OxiMax N-600x Operator's Manual page 121

Using the Data Port
Selecting the STEP softkey causes the voltage to increase from 0
th
to 1 volt at 1/10 -volt increments, with each step lasting at least
1 second.
Nellcor recommends that a qualified service personnel perform
the calibration of the attached device as described in the
N-600x Service Manual.
N-600x Operator's Manual 113