A method for activating a performance feature of a first communication transmission device, characterized in that a. based on a text- or multimedia message (AKTSMS) entering a connection control in the first communications terminal or associated with the first communications terminal from a transmitter designed as a communications terminal, from the entering text- or multimedia message (AKTSMS) a first address information specifying the first communications terminal is detected which corresponds to a target address (RUNOGW) for the text- or multimedia message (AKTSMS), wherein the first communications terminal represents a receiver of the text- or multimedia message (AKTSMS)and the receiver of the text- or multimedia message (AKTSMS)is activated by addressing with the first address information which is used in signaling to and/or from the first communications terminal, a second address information specifying the transmitter of the text- or multimedia message (AKTSMS)is detected which is used in signalings to and/or from the transmitter, b. an authentication of the transmitter is carried out in that a check is made whether the detected, second address information for the detected first address information was stored in an assigned manner, and c. as a consequence of a positive checking result the performance feature is activated. a. based on a text- or multimedia message (AKTSMS) entering a connection control in the first communications terminal or associated with the first communications terminal from a transmitter designed as a communications terminal, from the entering text- or multimedia message (AKTSMS) a first address information specifying the first communications terminal is detected which corresponds to a target address (RUNOGW) for the text- or multimedia message (AKTSMS), wherein the first communications terminal represents a receiver of the text- or multimedia message (AKTSMS)and the receiver of the text- or multimedia message (AKTSMS)is activated by addressing with the first address information which is used in signaling to and/or from the first communications terminal, a second address information specifying the transmitter of the text- or multimedia message (AKTSMS)is detected which is used in signalings to and/or from the transmitter, a first address information specifying the first communications terminal is detected which corresponds to a target address (RUNOGW) for the text- or multimedia message (AKTSMS), wherein the first communications terminal represents a receiver of the text- or multimedia message (AKTSMS)and the receiver of the text- or multimedia message (AKTSMS)is activated by addressing with the first address information which is used in signaling to and/or from the first communications terminal, a second address information specifying the transmitter of the text- or multimedia message (AKTSMS)is detected which is used in signalings to and/or from the transmitter, b. an authentication of the transmitter is carried out in that a check is made whether the detected, second address information for the detected first address information was stored in an assigned manner, and c. as a consequence of a positive checking result the performance feature is activated.