The card swiped by the teacher at the reader outside the classroom only serves to open the classroom door.
The card swiped by the student at the reader inside the classroom is used to record the student’s presence in class.
For class attendance to be correctly recorded, the card must be swiped at the reader from 10 minutes before the start of the lesson until 10 minutes before the end of the lesson, i.e.:
In a lesson from 8:00 to 9:30, the card must be swiped at the reader from 7:50 to 9:19;
In a lesson from 9:30 to 11:00, the card must be swiped at the reader from 9:20 to 10:49.