This part of IEC 61375 specifies the data communication bus inside consists that are based on CANopen. CANopen was developed for use in, but is not limited to, industrial automation applications. These applications may include devices such as input/output modules, motion controllers, human machine interfaces, sensors, closed-loop controllers, encoders, hydraulic valves or programmable controllers. In the application field of rail vehicles CANopen networks are utilized to network subsystems in consists such as e.g. brake control system, diesel engine control system and interior or exterior lighting control system. In addition CANopen is utilized as consist network to enable the data exchange between the different subsystems within one single rail vehicle or a group of rail vehicles sharing the same Consist Network. This part of IEC 61375 applies to all equipment and devices operated on a CANopen-based consist network within TCN architecture as described in IEC 61375-1. The applicability of this standard to a TCN implementation allows for individual conformance checking of the implementation itself and is a pre-requisite for further interoperability checking between different TCN implementations. In any case, proof of compatibility between Train Backbone and the Consist Network will have to be brought by the supplier. This part of IEC 61375 applies to the architecture of communication systems in Open trains. In addition it may be applicable to closed trains and multiple unit trains when so agreed between purchaser and supplier.