An enduser at a POTS analog voice-only endpoint (136) and endusers at H.320 standard multimedia terminals (101, 102, 103, 104), which each communicate over separate voice, video and data streams, engage in a videoconference with each other in a pseudo multimedia manner through a central platform (135) that provides call conversion capabilities. A document to be shared by a user at the POTS endpoint with users at the multimedia endpoints is transmitted as a data signal from a facsimile machine (137) or PC terminal (138) associated with the POTS user to a server (146) in the platform. The received data signal is then inputted to a multimedia bridge (124) and transmitted on the data stream to each multimedia endpoint for display on a window on each multimedia terminal. Similarly, a document to be shared by a multimedia endpoint is transmitted on a data stream to the multimedia bridge, where it is bridged on the data stream transmitted to the other multimedia endpoints and to the server. The document is then transmitted from the server to the facsimile machine or PC terminal associated with the POTS endpoint. In conventional multimedia conferencing arrangements, voice-activated switching is used to determine which user's video image is bridged onto the video stream transmitted to each multimedia terminal. When the audio signal from the POTS user would cause a video signal from that user's terminal to be bridged to all the multimedia endpoints if in fact that user was at a multimedia terminal, a stored image of that user is retrieved from a database (151) and outputted by the bridge on the video stream transmitted to each multimedia terminal to enable the multimedia participants to visually identify the presently talking enduser.