Abstract: The circuit-oriented components of at least one function area of a communication system are combined on at least one area module. For a configuration of the communication system, a combination--determined by the central controller and stored in this controller--of a circuit technology identification and at least one function identification is transmitted to the respective area module and is stored there in the sense of a specification of the circuit-oriented and procedural functions of the area module. At least one program module allocated to the combination of a circuit technology identification and at least one function identification is transmitted to the respective area module, using the central controller, and is stored in this controller.

Abstract: The controller of the switching system has a switching-oriented program that has two program parts allocated to it. A first program part is designed for processing call number information that has a first plurality of call number digit information. The second program part is designed for processing call number information that has a second, greater plurality of call number digit information. In the method of the invention, the call number plan of a private branch exchange is designed for a public switching system.