The core of the biometric time and attendance system is a biometrics-enabled clocking unit that relies on measurements of physical characteristics such as fingerprints, facial shape, iris, or eye shape, or even a vocal sample to log an employee into the timekeeping system and record their attendance. The scan or sample matches an existing record in the database, ensuring that only your employees have access to the system — if the scan doesn't match an existing record, access will be denied.