The access control system can be divided into the following three categories according to the access identification method:
1. Password identification: identify the access authority by checking whether the password is correct. This kind of products can be divided into two categories: one is the disordered keyboard type (the numbers on the keyboard are not fixed and change automatically from time to time)
2. Card identification: identify the access authority by card reading or card reading plus password, which can be divided into magnetic card and RF card according to card type
3. Portrait recognition: identify the entrance and exit by means of biometrics of inspectors. There are fingerprint type, iris type and face recognition type.