This part of IEC 61375 specifies rules for the data exchange between consists in trains. The aggregation of these rules defines the TCN communication profile. The objective of the communication profile is to ensure interoperability between consists of the said trains with respect to the exchange of information. For this it defines all those items which are necessary for communication interoperability: - an architecture with defined train directions related to different train views - a common functional addressing concept - common communication protocol for data exchange between functions - a set of services for train communication control.