Circuits or subsystems at CAN nodes generally have software that uses protocals that implement the upper 5 levels of the 7-layer OSI model. In the automotive market, vehicle manufacturers use proprietary CAN protocols. In the industrial market, the most commonly used standard protocols are CAN Open and DeviceNet. CAN Open was developed as a standardized embedded network with highly flexible configuration capabilities. Now it is used in many fields, such as medical equipment, off-road vehicles, public transportation, and building automation. The CAN Open specifications cover the application layer and communication profile. They also provide a framework for programable devices; recommondations for cables, connectors and SI units; and prefix representation. DeviceNet is an open low-level network protocol that provides connections between simple industrial devices such as embedded controllers and computers. The DeviceNet network is flexible and works with products from multiple vendors. It uses the proven Common Industrial Protocol (CIP) to provide control, configure, and data collection capabilities for industrial devices. Other standard CAN protocols include NEMA2000 for marine applications, CANaerospace for aircraft systems, SAE J1939 for heavy trucks and ISO11783 for agricultural vehicles. Incidentally, most of the protocols discussed here don't implement several of the intermediate levels of the OSI model because it isn't necessary to do so. The availability of these standardized higher-level protocols help system designers to build complex control applications effectiently. The combination of standard off-the-shelf CAN hardware and standard but customizable protocol software makes system development time more accountable and accurate.