Communication terminal device and method of controlling same

摘要

A communication terminal device which comprises an SIP call control unit that performs call control by using an SIP (Session Initiation Protocol), a recognition unit that recognizes that a calling has become an error according to a response signal sent back from a called party terminal after making the call according to the SIP call control procedure, a redial management unit that manages a redial interval to make a redial when the calling has become an error, and a redial control unit that performs redial control according to redial information when the calling has become an error and the response signal contains the redial information.