BACnet (Building Automation and Control Network) is a communication protocol specifically designed for building automation and control systems. It was established by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) in 1995 and has been adopted by the International Organization for Standardization (ISO) as a standard (ISO 16484-5). BACnet aims to enable interoperability between devices from different manufacturers, particularly those involved in Building Management Systems (BMS), such as HVAC, lighting control, security systems, fire alarms, and more. BACnet supports various transmission media, including IP networks, RS-485, ARCNET, and MS/TP (Master-Slave/Token Passing), making it adaptable to different installation environments. Its ability to integrate and manage multiple devices in automation systems has made it one of the most widely used communication protocols in modern smart buildings.

The BNET-2119M is a BACnet/IP IO module, featuring 9 Relay output channels. The module contains multiple BACnet objects, including Device, BO, and supports various BIBBS (such as DS-RP-B, DS-RPM-B, DS-WP-B, DS-WPM, DS-COV-B, etc.). The module has a built-in web server, allowing users to easily and securely configure the module remotely via a web interface.