Dahua Technology ASA1222E-S - 3.7.4 Device Info

Appendix 1 Note of Fingerprint
Warning
 Before you press your finger on the collector, please make sure your finger is clean
without oil or water.
 When you record fingerprint, place finger flat at the center of collector.
Recommended Fingerprint
Index finger, middle finger and ring finger are recommended.
Figure A-1
How to Press
 Correct method
Figure A-2
 Wrong method