Currently QuickTime Conferencing does not support dial-up (modem) connections. You need either an ISDN card, or other direct connection method to use QuickTime Conferencing. ISDN modems using a PPP/TCP/IP connection are also not supported.
This article was published in the Information Alley on 29 March 1996.
Article Change History:
29 Mar 1996 - Added information about ISDN modems not being supported.