Hello gabo
The LED indicator on the SCC or AUX board indicates whether the subrack is a master or slave subrack when subracks are cascaded.
"0" indicates the master subrack.
"EE" indicates that the subrack ID is incorrect or cannot be read.
Other values indicate slave subracks. For example, "1" indicates slave subrack 1, and "2" indicates slave subrack 2.