The purpose of this leaflet is to describe the data transmission system used as carrier for international IT applications of railway organisations (RO) and to define the appropriate standards and components.
This data transmission system is subsequently referred to as the "HERMES" system.
In order to make it possible for the ROs to use the HERMES system and to communicate with one another, it is necessary to make obligatory specifications of the connection characteristics for network access and security, of protocols and functions, of regulations at user level, of message structure etc. These regulations must strictly be observed by all users of the HERMES system, as otherwise any data communication between ROs will be impossible or lead to system breakdowns.