Communication terminal device, communication system, and communication control method

摘要

The first communication unit 101 performs data communication in a first communication mode specializing in packet communication via a first communication system A. The second communication unit 102 performs data communication in a second communication mode supporting voice communication via a second communication system B. The control unit 109 controls the first communication unit 101 and second communication unit 102. The control unit 109 controls the first communication unit 101 to perform data communication via the first communication system A until a voice communication start instruction is received. The control unit 109 determines whether to perform data communication via the second communication system B based on access control information on the second communication system B in response to the reception of a voice communication start instruction.