A method for controlling an access node interface connected to a VoIP server via an IP-based network, wherein subscriber lines connect a plurality of subscriber terminals to the access node, includes storing subscriber-specific data in a memory device associated with the VoIP server, where the data contains information to configure an access node voice interface. The access node determines whether at least one of the plurality of subscriber terminals is connected to the interface. If at least one of the subscribers is connected to the interface, then interface-associated identification data is transmitted from the access node to the VoIP server using an IP-based protocol. In response to the interface identification data received, subscriber-specific data filed for the connected interface is transmitted from the VoIP server to the access node using the IP-based protocol. The access node is configured, using the subscriber-specific data, so that the interface is operated as a voice interface.