Wireless antenna extension module is an important component of access control systems. Its function: to resolve the wireless door lock between the master and wireless access wireless signal is too weak as a result of the problem can not communicate properly. Antenna extension module RS485 master access wireless access, and wireless access through the lock 2.4GHz wireless connection, in order to achieve real-time communication capabilities. Under a master wireless access up to 16 expansion modules can be connected, an extension module can connect up to six wireless door to door.