The C3-400 is a controller for proximity cards for 4 doors. C3-400 controllers aim to improve security and efficiency in access control. They are specially designed for use in offices and companies. To connect the C3 to a management software, users can choose between communication via Ethernet or serial, which allows a large number of terminals to be communicated. It is advisable and safe for users who connect with other security devices. It has an application in a Web environment that helps administration and supervision in real time.