LonTalk is a legacy communication protocol developed by Echelon Corporation, primarily used for networking devices in building automation and control systems. It enables interoperability among devices such as lighting, HVAC, and security systems by providing a standardized way for them to exchange information. LonTalk operates on the LonWorks platform and supports various physical media, including twisted pair, power line, and fiber optics. Although once widely adopted for building management, its use has declined in favor of newer protocols like BACnet and KNX. Despite this, many legacy systems still rely on LonTalk for device communication and integration.