Patent ID: 7565133

Claim:
A communication terminal for performing at least partly simultaneous voice communication and data communication with a correspondent terminal, comprising: a first communication controller that establishes a circuit-switching communication line to the correspondent node; a second communication controller that establishes a packet-switching communication line to the correspondent node, wherein the communication terminal uses packet-switching communication via the packet-switching communication line at least partly concurrently with communicating via the circuit-switching communication line; data sending-receiving unit that sends and receives data using the packet-switching communication line established by the second communication controller; and notifying unit configured to notify that the data sending-receiving unit has received data while performing the circuit-switching communication, wherein the second communication controller establishes the packet-switching communication by: sending a connection request message to a gateway apparatus, the connection request message including subscriber information of the correspondent node, receiving a connection response message from the gateway apparatus, the connection response message including a data communication address of the correspondent node, and establishing the packet communication line dedicated to data communication to the correspondent node.