To enter the calibration date, use the CDATE command (cdate [YYYYMMDD]). To enter a text string with information about the calibration, use the CTEXT command (ctext [string]).
CDATE [yyyymmdd] <cr>
CTEXT [text string] <cr>
Example:
cdate 20151125
Cal. date : 20151125
ctext Calibrated in Room 1
Cal. info : Calibrated in Room 1