A dedicated UR5213 (21 slots) is used for the GDM. The CP52M0 memory module (slot 1) and an appropriate number of CP52IO interface modules (slots 2 to 12) are specified for this.

An CP52A0 access module is required in every subrack which is coupled to the GDM.

The subracks are connected in a star topology to the GDM with glass fiber-optic cables.