In the ETCS system , some variables require some kind of co-ordination during use of it, including the definition of who is assigning new values because care has to be taken not to assign identical values for different purposes or vice versa. Reasons for this may be functional or safety related.
Based on the functionality behind each variable, a list for the organisations responsible for assigning values to them has been established (see section 18.104.22.168 of Subset-054) and can be classified as follow:
- for variables which need international co-ordination, the ERA maintains public tables allocating unique values or range of values to the requesting organisations,
- for variables which need national co-ordination, the Member States are responsible for assigning unique values.