NFC
Unlock the phone, hold it to the NFC tag, done. The chip produces a new signed code on every touch; the scheme is designed to reject copies and repeated codes.
QR code
The QR code on the location sign only opens the app's download page — it is not a way to clock in. Once you have the app you no longer need it.
Location clock-in
Phones without NFC clock in with «I am here» and «I am leaving» in the app. The server accepts the time entry only if the phone is inside the location zone and the accuracy is under 50 metres. Only «inside / outside» is stored, never a coordinate.
Without internet
An NFC time entry is queued on the phone with its signature and device time and sent as soon as there is a connection again (up to 24 hours; the manager sees the note «late sync»). Location clock-in needs internet, because the server has to check place and time.
Forgotten
If a time entry is missing, the manager adds it under Attendance → Corrections. A reason is mandatory, and the old value stays in the log.
