AMT Datasouth Fastmark M1/203dpi User Manual page 11

5. Close the top cover gently and make sure the cover latches securely.
6. Use "Diagnostic Tool" to set the media sensor type and calibrate the selected sensor. (Start
the "Diagnostic tool"  Select the "Printer Configuration" tab  Click the "Calibrate Sensor"
button)
Note: Please calibrate the gap/black mark sensor when changing media.
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