One important point is that the barcode of the ID card is relatively long, so it is suggested that you do not stick it when scanning. Besides, watch the video. The barcode of the ID card is not placed in the fov, so it will cause bad scanning.
please refer the guide :
T20 hardware barcode scaner setting:http://service.telpo.net:8091/index/user/fetfile?key=ERC08LWU6wJZAy5Q