Patent ID: 8014383

Claim:
A communication system for audio communication over a network, comprising: a first IP phone; a second IP phone; and an audio control server, wherein: the second IP phone comprises: a receiving-side connection controller to control a receiving-side connection interface with a receiver's mobile phone and to obtain a phone number of the receiver's mobile phone being connected to the second IP phone; and a connect information transmitter to transmit connect information including identification information and the phone number when the receiver's mobile phone is connected to the second IP phone; the audio control server comprises: a connect information manager to store and manage the connect information received; and a communication controller, once determining based on the connect information that the receiver's mobile phone is not connected to the second IP phone when receiving a request to call the receiver's mobile phone from the first IP phone, to transmit a connection unable notification to the first IP phone; and the first IP phone comprises: a calling-side connection controller to control a calling-side connection interface with a caller's mobile phone; and an audio interface controller, when sending the request to the audio control server to call the receiver's mobile phone and receiving the connection unable notification, to cancel the request to the audio control server and to request the caller's mobile phone being connected to the first IP phone to call the receiver's mobile phone through a mobile phone network which bypasses the first IP phone, so as to establish communication between the caller's mobile phone and the receiver's mobile phone, wherein the first IP phone communicates with the receiver's mobile phone through the caller's mobile phone and the mobile phone network.