Telephone relay device, teleconference server, teleconference system, telephone relay method, and program

A teleconference server comprising:

• a server-side relay unit configured to relay an audio call between communication terminals participating in a teleconference via an Internet Protocol (IP) network;
• a notification unit configured to transmit an audio quality reduction notification to a telephone relay device when audio quality of the audio call between the communication terminals becomes less than a predetermined level;
• and
• a participation processing unit configured to permit participation in the teleconference in response to receiving a request for permission to participate in the teleconference from the telephone relay device, wherein the telephone relay device comprises a call making unit configured to make a call to a telephone terminal associated with the communication terminal in response to being permitted to participate in the teleconference,
• wherein the server-side relay unit transmits and receives audio call data of the teleconference to and from the telephone terminal associated with the communication terminal via the telephone relay device participating in the teleconference.

A telephone relay method for a telephone relay device being communicably connected to a teleconference server configured to relay an audio call between communication terminals participating in a teleconference via an Internet Protocol (IP) network, the telephone relay method comprising:

• requesting the teleconference server to permit participation in the teleconference in response to receiving an audio quality reduction notification indicating that audio quality of the audio call between the communication terminals becomes less than a predetermined level, from the teleconference server;
• making a call, by a call making unit, to a telephone terminal associated with the communication terminal in response to being permitted to participate in the teleconference;
• and
• relaying an audio call of the teleconference between the telephone terminal and the teleconference server in response to receiving a response to the call from the telephone terminal.