ISO 12855:2011 specifies

• the interfaces between electronic fee collection (EFC) systems for vehicle related transport services, e.g. road user charging, parking and access control; it does not cover interfaces for EFC systems for public transport; an EFC system can include any EFC system, e.g. also systems automatically reading licence plate numbers of vehicles passing a toll point;
• an exchange of information between the central equipment of the two roles of service provision and toll charging, e.g.
• charging related data (toll declarations, billing details),
• administrative data, and
• confirmation data;
• transfer mechanisms and supporting functions;
• information objects, data syntax and semantics;
• examples of data interchanges.

ISO 12855:2011 supports any toll service and any technology used for charging.

It is defined as a toolbox standard of transactions and messages which can be used for the assigned purpose. The detailed definitions of mandatory and optional elements in a real implementation are defined elsewhere. It does not define all communication sequences, communication stacks and timings.