5.9. Customer Groups, Shared Systems CUG 
OpenScape 4000 enables
several customers to share a common system. The 16 ITR and 16 DPLN groups
afford various possibilities of organizing such a system.
The following options exist:
- Assigning stations to any of the 16 ITR groups in such a way that the terminals of one customer may belong to one or several ITR groups and the terminals of the other customers cannot be dialled up internally.
- Assigning the trunk circuits to specific customers but allocating common routing codes to all customers. The DPLN at the terminal causes only those routes to be seized that are allocated for that user station. The ITR group of the trunk circuit will establish connections only to those stations to which traffic is allowed i.e. established via the ITR matrix.
- Trunk circuits may also be required and shared by several customers. In a different arrangement each customer can use his trunk groups in the outgoing direction and share them with other customers in the incoming direction.
- Providing the same service/access code numbers for all customers or entering several code numbers per service. The same applies to the attendant access code or the code for "trunk answer from any station/universal night answer".
- Implementing the class-of-service changeover either separately for each customer or for all customers by assigning the relevant changeover groups on terminal setup.
- Allocation of NON-VOICE terminals to STN either separately or system-wide by way of the TGER AMO
Features are always enabled or disabled for the complete system with the
FEASU AMO. Disabling of features for specific customers is possible only
by means of omitting certain access codes for a customer-specific DPLN.
It is not possible to define specific quantities for each customer
with the DIMSU AMO (e.g..: 10 hunting groups for customer A and 20 for
customer B). This type of layout is always defined for the complete system.
The central speed dialling facility, consisting of 16 groups, is so
conceived that groups 1-15 only may be allocated to specific stations.
Group 0 is the common group i.e.shared by all stations.