This part of IEC62580 , which is a Technical Specification, specifies the on-board video surveillance/CCTV system functionality and requirement for the purpose of interoperability between components of on-board video surveillance/CCTV systems in the same vehicle and subsystems in different vehicles of the same train, which means two levels of interoperability are considered, one is interoperability between components and another is between subsystems. This specification gives guidelines for: system breakdown structure of the on-board video surveillance/CCTV system; function breakdown structure of the on-board video surveillance/CCTV system, and requirement of the on-board video surveillance/CCTV system. This specification is applicable to any type of train, for example open trains, multiple unit trains and closed trains. As illustrated in Figure1, this part of IEC62580 provides video surveillance/CCTV services of monitoring, recording and retrieval of data, etc. This specification follows the general OMTS requirement defined in IEC62580‑1 . The communication network of on-board video surveillance/CCTV system is based on the network defined by the IEC61375 series, in which IEC61375‑2‑5 and IEC61375‑3‑4 define communication between and within consists, respectively, IEC61375‑2‑3 lays out the communication profile for the backbone which is used for the train coupling, and IEC61375‑2‑6 1 provides the support for the communication between on-board system and ground wayside infrastructures. The general system requirement of on-board video surveillance/CCTV system is developed based on IEC62676 series with supplementing the special requirement for railway application. For interoperability implementation between components of system and subsystems, this specification makes reference to IEC62676‑2‑3 , which specifies a compliant IP video protocol and interface based on Web services. Special requirements for railway, such as device discovery between consists and within a consist, as well as network compliant to the IEC61375 series are also defined here. In addition, IEC62676‑4 gives recommendations and requirements for the selection, planning, installation, commissioning, maintaining and testing for use in security applications. Finally, the requirement of exported data of on-board video surveillance/CCTV system is compliant with ISO22311 if system is for security purpose. [Image removed.]