The invention relates to a method for establishing a telecommunications link (C1, C2, C3), controlled by a control program (28), with a second communications terminal (D1), according to which a CTI service is made available to the first communications terminal (36) by a CTI server (20) in a CTI domain allocated to said CTI server (20), and the second communications terminal (D1) is located outside the CTI domain and by way of a proxy (Trk2) situated within the CTI domain is linked to the CTI server (20). The control program (28) is linked to the CTI server (20) by way of an intermediate functional unit (30, 32). The intermediate functional unit (30, 32) signals to the control program (28) that the second communications terminal (D1) instead of the proxy (Trk2) is linked into the established telecommunications link (C1, C2, C3) as the telecommunications terminal. The intermediate functional unit (30, 32) instructs the CTI server (20) to carry out the CTI service on the proxy (Trk2) in accordance with the control program (28). Furthermore, an intermediate functional unit (extra domain device, CSP) can be implemented as additional server or middleware. The invention further provides a corresponding system.