"This protocol provides a comprehensive set of messages for conveying encoded binary@ analog@ and alphanumeric data between devices including@ but not limited to: (a) hardware binary input and output values@ (b) hardware analog input and output values@ (c) software binary and analog values@ (d) text string values@ (e) schedule information@ (f) alarm and event information@ (g) files@ and (h) control logic. This protocol models each building automation and control computer as a collection of data structures called ""objects@"" the properties of which represent various aspects of the hardware@ software@ and operation of the device. These objects provide a means of identifying and accessing information without requiring knowledge of the details of the device's internal design or configuration. PURPOSE The purpose of this standard is to define data communication services and protocols for computer equipment used for monitoring and control of HVACR and other building systems and to define@ in addition@ an abstract@ object-oriented representation of information communicated between such equipment@ thereby facilitating the application and use of digital control technology in buildings."