The LNL-X4420 is an Advanced Dual Reader Controller that provides a single-board solution for interfacing up to 64 doors, plus auxiliary inputs and outputs, to an OnGuard system. The LNL-X4420 controller enables Ethernet connection directly from an entry location to the OnGuard server. In addition, other I/O and reader interface modules can be added on the controller's two downstream ports, further expanding its capabilities. In the event of communication loss, the LNL-X4420 controller can maintain most of its local functionality until the server connection is restored. The LNL-X4420 controller can act as an interface to building automation systems via the ASHRAE BACnet protocol. Through the OnGuard software, up to 63 total BACnet points can be defined. These can be a mix of physical inputs connected to the board and virtual outputs. Virtual outputs can be set and read from a connected BACnet client, allowing two-way state exchange with a variety of building control systems. This information can be used by both OnGuard and the external system for status reporting, and as inputs to control logic.