ISO/IEC 14908-2:2011 specifies the control network protocol (CNP) free-topology twisted-pair channel for networked control systems in local area control networks and is used in conjunction with ISO/IEC 14908-1. The channel supports communication at 78,125 kbit/s between multiple nodes, each of which consists of a transceiver, a protocol processor, an application processor, a power supply and application electronics.

ISO/IEC 14908-2:2011 covers the complete physical layer (OSI Layer 1), including the interface to the Media Access Control (MAC) sublayer and the interface to the medium. Parameters that are controlled by other layers but control the operation of the physical layer are also specified.