Early Building Automation Systems
Building automation systems communicate with a special "language" called a protocol. In the early years, each manufacturer had it's own proprietary protocol. Building owners who purchased proprietary protocols were likely locked to a sole source vendor. In this type of relationship, building owners would be forced to pay the proprietary vendor's price for additions and maintenance, or replace the entire system at an enormous expense. The demand for open inter-operable system lead to the development of the LONNWORKS and BACNET protocols.