... voice service Anonymous call, Direct IP Call and Busy tone Fax over IP and Three –way conferences Multiple FXS ports optionalDAG 2000 ... forwarding, caller ID, DND, busy tone, conference with IPPBX and Fax over IP.Be easy to configure and maintain:Customer can access ... waiting, Call display etc standard voice service and Busy tone, Fax over IP, Three-way conference . Support PPPoE client , ensure voice ...