The present invention relates a communication terminal for the synchronisation of audio and visual information within a communication system. Audio communication between the parties to a video conference is achieved by digitising the speech and transmitting the same over a packet based data network. Each party to the conference can draw the attention of the other party to an object on the screen using a pointer controlled by, say, a mouse or ball. The co-ordinates of each parties' pointer are incorporated, via a multiplexer, into the data packets containing the digitised speech and transmitted to the other party's terminal thereby ensuring the synchronisation the pointer information with the digitised speech.