A method and an arrangement are specified for setting up and clearing communications links via a private branch exchange. The transport network for transporting the communication data is preferably in the form of an ATM network or IP network, and is controlled by a separate control network, separated from it. The advantage is that the two networks are independent of one another, and that broadband communications requirements can be satisfied easily by a modular expansion capability. The central control configuration allows already existing central databases relating to subscribers to be used, and likewise allows connection-related service feature control systems still to be used.