Network access control system is through the electronic
identification devices (such as magnetic card, radio frequency
card) or biometric means (such as voice, iris, fingerprint) to
identify the identity of those who want to open the door, and
set permissions based on pre-decision to open the door or alarm
signal. Access control system to use more common RS-485 bus,
to achieve communication between control hosts and
identification devices. This connection, each identification
device special wiring needed to connect to the control
computer, a construction difficult, expensive, difficult to meet
the network anytime, anywhere access and control the times
demand, adopt Ethernet as the communication channel between
control hosts and identification device, using TCP/IP network
traffic patterns, and easy to implement communication between
access control host and the embedded controller, wiring simple,
low cost, post-maintenance more convenient.