Abstract: Acoustic information which is generated via telecommunications terminals such as ordinary telephone sets may reach a videotelephone located at the other end of a telecommunications connection in an insufficiently clear degree, if at all, while the videotelephone is conducting an investigation into the kind of telecommunications terminal which is located at one end of the telecommunications connection. By providing the telecommunications terminal with a detection circuit for the detection of a first signal of a previously established type, and providing it with an activating circuit coupled to the detection circuit for generating, in response to the detected first signal of the previously established type, an activating signal for the prevention of the premature transmission of second signals, the above-mentioned possibility is strongly reduced.