A video telecommunication connection is established via a landline telecommunications network and an IP multimedia subsystem telecommunications network using a media gateway control function of at least one Internet multimedia-media gateway device in the IP multimedia subsystem telecommunications network. An H.223 multiplex level usable for a telecommunication connection is exposed to an H.223 protocol negotiation, in carrying out an H.245 protocol negotiations for setting up the H.223 protocol negotiations connection for a telecommunication connection. A media gateway control function device is informed when the H.223 logic channels are open by H.245 signaling, thereby enabling the Internet multimedia-media gateway device of the IP multimedia subsystem telecommunications network to carry out at least part of the setup.