SN EN 50159-2 : 2001

Introduction
1 Scope
2 Normative references
3 Definitions
4 Reference architecture
5 Threats to the transmission system
6 Requirements for defences
   6.1 Introduction
   6.2 General requirements
   6.3 Specific defences
7 Applicability of defences against threats
   7.1 Introduction
   7.2 Threats/defences matrix
   7.3 Choice and use of safety codes and
       cryptographic techniques
Annex A (informative) Guidelines for defences
   A.1 Applications of time stamps
   A.2 Choice and use of safety codes and
       cryptographic techniques
Annex B (informative) Bibliography
Annex C (informative) Guidelines for use of the standard
   C.1 Scope/purpose
   C.2 Classification of transmission systems
   C.3 Procedure
   C.4 Example
Annex D (informative) Threats on open transmission systems
   D.1 System view
   D.2 Derivation of basic message error
   D.3 Threats
   D.4 A possible approach for building a safety case
   D.5 Conclusions

Describes the basic requirements needed in order to achieve safety related transmission between safety related equipment connected to the open transmission system, in order to obtain the allocated safety integrity level.