This part of IEC 62026 specifies an interface system between single or multiple controllers, and control circuit devices or switching elements. The interface system uses two twisted shielded conductor pairs within one cable - one of these pairs provides a differential communication medium and the other pair provides power to the devices. This part establishes requirements for the interchangeability of components with such interfaces. This part of IEC 62026 specifies the following particular requirements for DeviceNet: - requirements for interfaces between controllers and switching elements; - normal service conditions for devices; - constructional and performance requirements; tests to verify conformance to requirements. These particular requirements apply in addition to the general requirements of IEC 62026-1.