A voice conference bridge provides respective voice connections to a call coordinator and a plurality of call participants. A message server is coupled to the voice conference bridge for receiving DTMF tone messages from the call coordinator and the call participants and for sending data messages in a caller ID format to the call coordinator and the call participants via the voice conference bridge. The message server interacts with the call participants using a participant-initiated request channel and a server-initiated broadcast channel. A particular call participant invokes the request channel by including a predetermined tone command in a respective DTMF tone message. The particular call participant forwards a message content to the message server by including predetermined tone data in the respective DTMF tone message. The message server forwards the message content to other call participants via the broadcast channel according to an approval granted to the particular call participant.