In the Intoxilyzer 5000C and 5000 there was an internal calibration check system called "internal standards" (in addition to to external wet bath or dry gas). In the Intoxilyzer 8000C and 8000 there is a similar internal standards systerm called the "internal test procedure" or ITP. A Supervisor can adjust the 8000/8000C software to use W(etBath), D(ry Gas), or I(nternal Standards) as the control test method. See also p. 74 of 238 in the 2013 Training aid.