This International Standard specifies all the information necessary to facilitate the exchange of data and control information over the power line medium for networked control systems used in conjunction with ISO/IEC 14908-1. This International Standard establishes a minimal set of rules for compliance. It does not rule out extended services to be provided, given that the rules are adhered to within the system. It is the intention of the standard to permit extended services (defined by users) to coexist. Certain aspects of this standard are defined in other documents. These documents are referenced where relevant. In the case where a referenced standard conflicts with this International Standard, this part of ISO/IEC 14908 will prevail.