The Function identifier and Position in function attributes in the CNSCAX|GFX|1 class play a central role in the symbol description. They determine the "logical positioning" of the 2D connection with the corresponding function and the associated function connection. For this purpose, we consider a system in which functions and symbols are completely differentiated. This means in particular that there is a corresponding function instance CNSELEK|5|8|x for all groups of physical connections CNS_CP|4|3 that belong to a function.

The central classification information, which contains the decisive mappings, is shown as an example in the following table. We see a system with 6 connections (correspondingly 6 class instances of CNS_CP|4|3 ), which belong to 2 functions (2 function instances CNSELEK|5|8|x ) and are described by 6 symbol connections (6 instances of CNSCAX|GFX|1 ). This construction allows each symbol connection to be uniquely mapped to the function.