Patent ID: 8548473

Claim:
A wireless terminal device that selectively switches among a plurality of communication systems provided so as to overlap with each other for performing communication, the wireless terminal device comprising: an instruction reception unit which, when a predetermined communication is produced in a state where a location registration is performed in a first communication system and the predetermined communication is transferred from the first communication system to a second communication system, receives a transfer instruction signal in the first communication system; a communication request unit which, when the transfer instruction signal is received by the instruction reception unit, captures the second communication system and requests a start of the predetermined communication to which the transfer is instructed, in the second communication system; a communication processing unit which, after the start of the predetermined communication is requested, when receiving in the second communication system an enabling signal for the request for the start of the predetermined communication, performs the predetermined communication in the second communication system; and a storage unit which, after the start of the predetermined communication is requested, when the enabling signal is not received in the second communication system, stores a combination of information on a communication area section in the second communication system when the enabling signal is not received, and information on a communication area section in the first communication system when the transfer instruction signal is received; wherein when a combination of information on a communication area section in the second communication system at a time when a new transfer instruction signal is received in the first communication system by the instruction reception unit and the second communication system is newly captured and information on a communication area section in the first communication system at a time when the new transfer instruction signal is received matches with the combination stored in the storage unit, the communication request unit requests to the second communication system the start of the communication to which the transfer is instructed, after newly performing a location registration in a communication area section of the newly captured second communication system.