The system is based on 2 door controllers (EWSi) that are housed in a lockable cabinet the PPCU2 with an integral 13.8Vdc 3.5A switched mode power supply with battery back up facility (7Ah 12V battery not included) and includes an Ethernet connection (TCP/IP) allowing controllers to be connected to a LAN or WAN with the potential expansion to unlimited doors and unlimited distances. Additionally an RS485 bus connection is included on the controller that will link additional controllers to the same Ethernet connection. The integration of door monitoring, push to exit button inputs, free inputs, free outputs and 16 status LED’s all help make this a simple to install yet extremely flexible system.