Patent ID: 8170564

Claim:
A communication terminal apparatus comprising: a call control section configured to perform call control including call establishment and call disconnection for each of plural networks that are in accordance with different communication schemes, respectively; and a handover control section configured to request a handover from a source network with a first communication scheme to a target network with a second communication scheme, prevent the call control section from disconnecting a call with the source network after a disconnection request to disconnect the call with the source network is received from a server of the networks, when a call with the target network is not established in the call control section, after receiving the disconnection request to disconnect the call with the source network, for a call establishment waiting time period, wait for a notification of establishment of the call with the target network while preventing the call control section from disconnecting the call with the source network, allow the call control section to disconnect the call with the source network, when the notification of establishment of the call with the target network is received before the call establishment waiting time period expires, and quit the requested handover after the call establishment waiting time period expires, when the notification of establishment of the call with the target network is not received during the call establishment waiting time period.