A resistive touchscreen drifts slowly over time and needs to be recalibrated once in a while. Calibrate option allows users to either reset the calibration back to factory settings or to recalibrate specific to the condition of the touchscreen.
From the Main Menu -> Select Settings 
then select Calibrate
In case the ts is accidently recalibrated with erroneous settings and user is unable to use the touchscreen to recalibrate or reset to factory settings, Switch off the Xplorer TS, once off hold the power button in for ~7 seconds or until the reset calibration screen comes up. DO NOT connect the ts’ USB port to any device.
The following screen will appear, select "ok" to reset to Factory defaults:
