Patent Description:
In a teleconference system to be operated on the web, data communication delays and missing may occur depending on communication conditions of Internet Protocol (IP) networks. In this case, a trouble may occur in an audio call, and progress of a teleconference may be hindered. In order to avoid such a situation, it has been proposed to participate in a teleconference from a telephone terminal.

However, in order to participate in a teleconference from a telephone terminal, a procedure such as a speaker dialing a telephone number of the teleconference from the telephone terminal and inputting a password of the teleconference is required. Further, since the speaker often does not notice that audio quality is reduced, the above-described procedure is performed while waiting for another conference participant who notices interruption or delay of the audio to communicate to the speaker. Therefore, there is a problem that the conference is interrupted in the meantime.

Therefore, Patent Literature <NUM> discloses that an information processing apparatus monitors communication environment and causes a server apparatus to change signal transmission conditions of video and audio according to the communication environment, by focusing on processing of the information processing apparatus to be used by participants in a conference.

<CIT> and <CIT> are documents of the related art.

However, in the information processing apparatus described in Patent Literature <NUM> described above, since audio data having a low audio quality level is received when a communication state is reduced, there is a possibility that progress of a teleconference is hindered by that.

In view of the above-described problem, an object of the present disclosure is to provide a telephone relay device, a teleconference server, a teleconference system, a telephone relay method, an audio call relay method, and a program that are able to avoid hindrance to progress of the teleconference.

A telephone relay device according to an aspect of the present disclosure is communicably connected to a teleconference server that relays an audio call between communication terminals participating in a teleconference via an Internet Protocol (IP) network. The telephone relay device includes a participation request unit, a call making unit, and a call relay unit. The participation request unit requests 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. The call making unit makes a call to a telephone terminal associated with the communication terminal in response to being permitted to participate in the teleconference. In response to receiving a response to the call from the telephone terminal, the call relay unit relays an audio call of the teleconference between the telephone terminal and the teleconference server.

A teleconference server according to an aspect of the present disclosure includes a server-side relay unit, a notification unit, and a participation processing unit. The server-side relay unit relays an audio call between communication terminals participating in a teleconference via an IP network. The notification unit transmits 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. The participation processing unit permits participation in the teleconference in response to receiving a request for permission to participate in the teleconference from the telephone relay device. The server-side relay unit transmits and receives audio call data of the teleconference to and from a telephone terminal associated with the communication terminal via the telephone relay device participating in the teleconference.

A teleconference system according to an aspect of the present disclosure includes the above-described telephone relay device and the above-described teleconference server.

A telephone relay method according to an aspect of the present disclosure is a telephone relay method for a telephone relay device communicably connected to a teleconference server that relays an audio call between communication terminals participating in a teleconference via an IP network. The telephone relay method includes: 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 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.

A program according to an aspect of the present disclosure is a program for causing a computer to execute the above-described telephone relay method.

An audio call relay method according to an aspect of the present disclosure is an audio call relay method for a teleconference server that relays an audio call between communication terminals participating in a teleconference via an IP network. The audio call relay method includes: transmitting 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; permitting participation in the teleconference in response to receiving a request for permission to participate in the teleconference from the telephone relay device; and transmitting and receiving audio call data of the teleconference to and from a telephone terminal associated with the communication terminal via the telephone relay device participating in the teleconference.

A program according to an aspect of the present disclosure is a program for causing a computer to execute the above-described audio call relay method.

According to the present disclosure, it is possible to provide a telephone relay device, a teleconference server, a teleconference system, a telephone relay method, an audio call relay method, and a program that are capable of avoiding hindrance to progress of a teleconference because a telephone relay device participates in a teleconference and relays an audio call by a telephone terminal in a case where audio quality is reduced.

Hereinafter, the present disclosure will be described through example embodiments, but the invention according to claims is not limited to the following example embodiments. Further, not all of configurations to be described in the example embodiments are essential as a means for solving the problem. For clarity of explanation, the following description and the drawings are omitted and simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals.

First, a first example embodiment of the present disclosure will be described by using <FIG> is a block diagram illustrating a configuration of a telephone relay device <NUM> according to a first example embodiment. The telephone relay device <NUM> is a computer device that relays an audio call of a teleconference. The telephone relay device <NUM> is communicably connected to the teleconference server. Herein, the teleconference server is a computer device that relays an audio call between communication terminals participating in a teleconference via an Internet Protocol (IP) network, via an IP network.

The telephone relay device <NUM> includes a participation request unit <NUM>, a call making unit <NUM>, and a call relay unit <NUM>.

In response to receiving an audio quality reduction notification from the teleconference server, the participation request unit <NUM> requests the teleconference server to permit participation in the teleconference. The audio quality reduction notification is a notification indicating that audio quality of the audio call between the communication terminals via the IP network becomes less than a predetermined level.

The call making unit <NUM> makes a call to a telephone terminal associated with the communication terminal in response to permission of the telephone relay device <NUM> to participate in the teleconference. Namely, the call making unit <NUM> calls the telephone terminal.

The call relay unit <NUM> relays the audio call of the teleconference between the telephone terminal and the teleconference server in response to receiving a response to the call from the called telephone terminal.

As described above, according to the first example embodiment, in a case where an IP network state occurs in which a communication delay or a loss occurs during a teleconference, the telephone relay device <NUM> participates in the teleconference, automatically establishes a connection of the audio call by the telephone terminal, and relays the audio call. Therefore, the telephone relay device <NUM> may avoid hindering the progress of the teleconference and continue the teleconference. On the other hand, since a user only needs to respond to the call, a burden on the user is reduced.

Next, a second example embodiment of the present disclosure will be described by using <FIG>.

<FIG> is a schematic configuration diagram of a teleconference system <NUM> to which a telephone relay device according to a second example embodiment can be applied. The teleconference system <NUM> is a computer system that provides a teleconference service to a user of a communication terminal. The teleconference system <NUM> includes a teleconference server <NUM>, a communication terminal <NUM>, an in-house telephone terminal <NUM>, and a private branch exchange (PBX) 30a as an example of the telephone relay device <NUM>. Although one communication terminal <NUM> is illustrated in this figure for clarity of explanation, it is assumed that the teleconference system <NUM> includes a plurality of communication terminals <NUM>. In addition, although one in-house telephone terminal <NUM> is illustrated in the figure, the teleconference system <NUM> may include a plurality of in-house telephone terminals <NUM>.

The teleconference server <NUM> is a computer device such as a server computer that relays data communication between the communication terminals <NUM> participating in a teleconference. The teleconference server <NUM> is connected to the Internet <NUM> as an example of an IP network and to a Public Switched Telephone Network (PSTN) as an example of a telephone line. In response to receiving audio data (audio call data) of the communication terminal <NUM> and other media data via the Internet <NUM>, the teleconference server <NUM> transmits these data to another communication terminal <NUM> participating in the teleconference via the Internet <NUM>.

When audio quality of the audio call becomes less than a predetermined level, the teleconference server <NUM> receives the audio call data from the in-house telephone terminal <NUM> usable by a user of the communication terminal <NUM> via a PSTN <NUM>.

The communication terminal <NUM> is a personal computer, a notebook computer, a tablet terminal, or other computer devices that can input and output data, which is used by a participant (user) of the teleconference. In this figure, the communication terminal <NUM> is connected to the Internet <NUM> via a switching hub <NUM> and a router <NUM>. The communication terminal <NUM> transmits audio call data generated in response to user's audio being picked up to the teleconference server <NUM> via the Internet <NUM>, and receives audio call data of another communication terminal <NUM> participating in the teleconference from the teleconference server <NUM>. Further, the communication terminal <NUM> transmits other media data such as image data to the teleconference server <NUM> and receives the other media data from the teleconference server <NUM> via the Internet <NUM>.

Therefore, in the network, traffic of audio call data and other media data is mixed, and thus, there is a problem that the audio quality of audio call is likely to be reduced.

The in-house telephone terminal <NUM> is an in-house telephone terminal usable by a user of the communication terminal <NUM>. The in-house telephone terminal <NUM> may be a fixed telephone or a mobile telephone. The in-house telephone terminal <NUM> is a telephone terminal under the control of the so-called PBX 30a, which is connected to the PBX 30a via an in-house line. When audio quality of an audio call by the communication terminal <NUM> is reduced, the user of the communication terminal <NUM> continues the audio call by using the in-house telephone terminal <NUM>.

The PBX 30a is a private branch exchange associated with a communication terminal. The PBX 30a is connected to the PSTN <NUM> and the in-house line. The PBX 30a is connected to the Internet <NUM> via the switching hub <NUM> and the router <NUM>. The PBX 30a is configured to participate in the teleconference and call the in-house telephone terminal <NUM> in response to receiving an audio quality reduction notification from the teleconference server <NUM>. The PBX 30a relays an audio call between the teleconference server <NUM> and the in-house telephone terminal <NUM>.

As a result, the teleconference server <NUM> receives audio call data from another communication terminal <NUM> or another in-house telephone terminal <NUM> participating in the teleconference, and transmits the audio call data to the in-house telephone terminal <NUM>. Thus, even when the audio quality of the audio call by the communication terminal <NUM> becomes low, the user of the communication terminal <NUM> can continue the audio call by using the in-house telephone terminal <NUM>.

<FIG> is a block diagram illustrating a configuration of the teleconference server <NUM> according to the second example embodiment. The teleconference server <NUM> includes a server-side relay unit <NUM>, an audio quality monitoring unit <NUM>, a notification unit <NUM>, a participation processing unit <NUM>, and a storage unit <NUM>.

The server-side relay unit <NUM> performs processing of relaying an audio call between the communication terminals <NUM> participating in the teleconference via the Internet <NUM>. Further, the server-side relay unit <NUM> transmits and receives audio call data of the teleconference to and from the in-house telephone terminal <NUM> associated with the communication terminal <NUM> by using the PSTN <NUM> via the PBX 30a participating in the teleconference. Namely, the server-side relay unit <NUM> continues to relay the audio call between the communication terminals <NUM> by using the PSTN <NUM> or by using the PSTN <NUM> and the Internet <NUM>.

The audio quality monitoring unit <NUM> monitors the audio quality of the audio call between the communication terminals <NUM> via the Internet <NUM> for each user participating in the teleconference, i.e., for each communication terminal <NUM>. The audio quality monitoring unit <NUM> may evaluate the audio quality by communication delay, jitter, packet loss, or the like.

When the audio quality evaluated by the audio quality monitoring unit <NUM> becomes less than a predetermined level, the notification unit <NUM> transmits an audio quality reduction notification to the PBX 30a via the Internet <NUM>. The case where the audio quality becomes less than the predetermined level may be, for example, a case where the communication delay, the jitter, or the packet loss is equal to or greater than a predetermined threshold, or a case where an index determined based on the communication delay, the jitter, and the packet loss is less than a predetermined threshold. The audio quality reduction notification includes identification information (ID) of the user of the communication terminal <NUM> whose audio quality is reduced, an ID and a password of a teleconference in which the user participates. The ID of the teleconference may be a dial-in number. This allows the PBX 30a to easily request permission to participate in the teleconference.

The participation processing unit <NUM> performs processing of permitting participation in the teleconference in response to receiving a request for permission to participate in the teleconference from the PBX 30a. The participation processing unit <NUM> notifies the PBX 30a of an ID of the in-house telephone terminal <NUM> associated with a target user in response to the permission of participation to the PBX 30a.

The storage unit <NUM> is a storage medium that stores an association table <NUM> to be described later.

<FIG> is a diagram illustrating an example of a data structure of the association table <NUM> according to the second example embodiment. The association table <NUM> associates the ID of the communication terminal <NUM>, the ID of the in-house telephone terminal <NUM>, and an ID of the PBX 30a with each other.

The ID of the communication terminal <NUM> may be an IP address or a Media Access Control (MAC) address. The ID of the in-house telephone terminal <NUM> may be a telephone number or an extension number. The ID of the PBX 30a may be an IP address or a MAC address.

The association table <NUM> may associate an ID of the user with the ID of the in-house telephone terminal <NUM> and the ID of the PBX 30a in place of or in addition to the ID of the communication terminal <NUM>. In addition, the association table <NUM> may store the ID and the password of the teleconference in association with the ID of the communication terminal <NUM>.

By using the association table <NUM>, the teleconference server <NUM> can easily and quickly notify the PBX 30a of the communication terminal <NUM> whose audio quality has reduced, and can also notify the ID of the in-house telephone terminal <NUM>.

<FIG> is a block diagram illustrating a configuration of the PBX 30a according to the second example embodiment. The PBX 30a includes an IP communication unit <NUM>, a participation request unit <NUM>, a call making unit <NUM>, and a call relay unit <NUM>.

The IP communication unit <NUM> communicates with the teleconference server <NUM> via the Internet <NUM>. Specifically, the IP communication unit <NUM> receives the audio quality reduction notification from the teleconference server <NUM>.

The participation request unit <NUM> requests the teleconference server <NUM> to permit participation in the teleconference by using the ID and the password of the teleconference included in the audio quality reduction notification.

The call making unit <NUM> makes a call to the in-house telephone terminal <NUM> through the use of the in-house line, by using the ID of the in-house telephone terminal <NUM> associated with the communication terminal <NUM>, which is notified in response to being permitted to participate in the teleconference.

In response to the response from the in-house telephone terminal <NUM>, the call relay unit <NUM> relays the audio call of the teleconference between the in-house telephone terminal <NUM> and the teleconference server <NUM> via the in-house line and the PSTN <NUM>.

As described above, since the PBX 30a relays an audio call by using a telephone line different from the Internet <NUM>, it is possible to avoid mixing with other media data and prevent reduction of audio quality. In addition, since the user continues the audio call via the PBX 30a, call charges can be borne by an organization (company).

<FIG> is a sequence diagram illustrating an example of a processing procedure of the teleconference system <NUM> according to the second example embodiment.

First, a user of the communication terminal <NUM> participates in a teleconference from a teleconference application of the communication terminal <NUM>, and performs an audio call and other data communication. At this time, the server-side relay unit <NUM> of the teleconference server <NUM> relays the audio call of the communication terminal <NUM> to the communication terminal <NUM> to be used by another participant via the Internet <NUM> (step S10). Then, it is assumed that the audio quality monitoring unit <NUM> of the teleconference server <NUM> detects reduction in audio quality (step S11). The notification unit <NUM> of the teleconference server <NUM> refers to the association table <NUM> of the storage unit <NUM>, identifies the PBX 30a associated with the ID of the communication terminal <NUM> to be targeted, and transmits an audio quality reduction notification to the PBX 30a via the Internet <NUM> (step S13). The audio quality reduction notification includes a dial-in number and a password of the teleconference.

In response to receiving the audio quality reduction notification by the IP communication unit <NUM> of the PBX 30a, the participation request unit <NUM> dials the teleconference and requests the teleconference server <NUM> to permit participation in the teleconference by using the password (step S14).

The participation processing unit <NUM> of the teleconference server <NUM> permits the PBX 30a to participate in the teleconference, and transmits a participation permission notification to the PBX 30a via the PSTN <NUM> (step S15). As a result, the PBX 30a is in a state of having participated in the teleconference. The participation processing unit <NUM> transmits a participation preparation notification indicating that participation in the teleconference is permitted to the PBX 30a, to the communication terminal <NUM> (step S16). As a result, the user of the communication terminal <NUM> can quickly switch to an audio call by the in-house telephone terminal <NUM>. Further, the participation processing unit <NUM> refers to the association table <NUM> of the storage unit <NUM>, specifies the telephone number of the in-house telephone terminal <NUM> associated with the ID of the communication terminal <NUM>, and notifies the PBX 30a of the telephone number via the Internet <NUM> (step S17). This step may be performed in parallel with step S15.

Then, the call making unit <NUM> of the PBX 30a makes a call to the in-house telephone terminal <NUM> via the in-house line by using the telephone number of the in-house telephone terminal <NUM> (step S18). At this time, the call making unit <NUM> may notify the in-house telephone terminal <NUM> to disconnect the audio call between the communication terminal <NUM> and the teleconference server <NUM>. As a result, duplication of the audio can be avoided, and the audio call can be switched smoothly.

The in-house telephone terminal <NUM> responds to an incoming call by user operation (step S19).

The call relay unit <NUM> of the PBX 30a, which has received the response, connects a call path between the teleconference server <NUM> and the in-house telephone terminal <NUM> (step S20). As a result, the call relay unit <NUM> starts to relay the audio call between the teleconference server <NUM> and the in-house telephone terminal <NUM> via the in-house line and the PSTN <NUM> (step S21).

On the other hand, in response to the response to the incoming call, the user disconnects the audio call between the communication terminal <NUM> and the teleconference server <NUM> by user operation (step S22). As a result, switching of the audio call is completed, and duplication of the audio is avoided.

In a case where the server-side relay unit of the teleconference server <NUM> starts to transmit and receive audio call data to and from the in-house telephone terminal <NUM>, the server-side relay unit may automatically disconnect the audio call to and from the communication terminal <NUM> associated with the in-house telephone terminal <NUM>. As a result, the audio call can be smoothly switched while reducing the burden on the user.

In addition, although the participation processing unit <NUM> of the teleconference server <NUM> notifies the PBX 30a of the telephone number of the in-house telephone terminal <NUM> in step S17, the ID of the communication terminal <NUM> or the ID of the user may be notified instead. The PBX 30a, which has received the notification, stores, in a storage unit (not illustrated), a table that associates the ID of the communication terminal <NUM> or the ID of the user with the telephone number of the telephone terminal that can be used by the user, and may identify the telephone number of the telephone terminal that makes a call by using the table. In this case, the ID of the in-house telephone terminal may be omitted from the association table <NUM> of the teleconference server <NUM>.

As described above, according to the second example embodiment, the teleconference system <NUM> switches the audio call to a telephone line with stable audio quality when an IP network state in which a communication delay or a loss occurs during the teleconference is established. Therefore, it is possible to avoid hindering the progress of the teleconference and to continue the teleconference.

Next, a third example embodiment of the present disclosure will be described by using <FIG>. The third example embodiment is characterized in that the PBX 30a relays an audio call between the teleconference server <NUM> and the in-house telephone terminal <NUM> via the Internet <NUM> instead of the PSTN <NUM>.

<FIG> is a schematic configuration diagram of a teleconference system 1b according to the third example embodiment. The teleconference system 1b is different from the teleconference system <NUM> in that the PBX 30a is connected to the Internet <NUM> via a switching hub <NUM> different from the switching hub <NUM> and a router <NUM>, instead of the PSTN <NUM>. In the router <NUM>, data (audio call data) with the switching hub <NUM> is preferentially passed by preferential control or the like, or domains of audio call data and data (other media data) with the switching hub <NUM> are divided and processed. Therefore, it is possible to avoid reduction in audio quality.

Therefore, instead of step S14 in <FIG>, the IP communication unit <NUM> of the PBX 30a requests the teleconference server <NUM> to permit participation in the teleconference via the Internet <NUM>. Instead of step S15 in <FIG>, the participation processing unit <NUM> of the teleconference server <NUM> transmits a participation permission notification to the PBX 30a via the Internet <NUM>. Instead of step S21 in <FIG>, the call relay unit <NUM> relays an audio call between the teleconference server <NUM> and the in-house telephone terminal <NUM> via an in-house line and the Internet <NUM>.

As described above, also in the third example embodiment, the same effects as those of the second example embodiment are acquired.

Next, a fourth example embodiment of the present disclosure will be explained by using <FIG>. The fourth example embodiment is characterized in telephone relay processing in a case where a user of the communication terminal <NUM> can use a plurality of telephone terminals of different types.

<FIG> is a schematic configuration diagram of a teleconference system 1c according to the fourth example embodiment. The teleconference system 1c has basically the same configuration and function as the teleconference system <NUM>, but is different from the teleconference system <NUM> in that it includes a mobile telephone terminal <NUM> and a PBX 30c instead of the PBX 30a.

The mobile telephone terminal <NUM> is a telephone terminal that can be used by a user of the communication terminal <NUM> in addition to the in-house telephone terminal <NUM>. The mobile telephone terminal <NUM> is a mobile telephone, a smartphone, or the like that can be connected to the PSTN <NUM>. When the audio quality of the audio call by the communication terminal <NUM> is reduced, the user of the communication terminal <NUM> selects either the in-house telephone terminal <NUM> or the mobile telephone terminal <NUM> and continues the audio call.

The PBX 30c has basically the same configuration and function as the PBX 30a, but is different from the PBX 30a in that the call making unit <NUM> acquires terminal type information of the telephone terminal selected by the user from the teleconference server and determines a line to be used for the call to the telephone terminal, based on the terminal type information. The line to be used for the call is, for example, an external line or an internal line.

<FIG> is a diagram illustrating an example of a data structure of the association table <NUM> according to the fourth example embodiment. The association table <NUM> according to the fourth example embodiment associates the ID of the communication terminal <NUM>, the ID of the telephone terminal, the terminal type, and the ID of the PBX 30c with each other. The terminal type is information indicating the type of the telephone terminal, and is, for example, an in-house telephone or a mobile telephone. The ID of the telephone terminal is an ID of the in-house telephone terminal <NUM> or the mobile telephone terminal <NUM>, and for example, when the terminal type is an in-house telephone, the extension number may be indicated, and when the terminal type is a mobile telephone, the mobile telephone number may be indicated. In this figure, the communication terminal <NUM> having an ID of "UE002" is associated with two telephone terminals having different terminal types, i.e., the in-house telephone terminal <NUM> and the mobile telephone terminal <NUM>. The ID of the communication terminal <NUM> may be associated with a plurality of telephone terminals of the same terminal type.

<FIG> is a sequence diagram illustrating an example of a processing procedure of the teleconference system 1c according to the fourth example embodiment. The same steps as those in <FIG> are denoted by the same symbols, and the description thereof will be omitted.

First, the teleconference system 1c executes the processing of steps S10 to S16.

Then, the participation processing unit <NUM> of the teleconference server <NUM> refers to the association table <NUM> of the storage unit <NUM>, and requests the communication terminal <NUM> to select a telephone terminal to be used when there are a plurality of telephone terminals associated with the target communication terminal <NUM> (step S30).

The communication terminal <NUM>, which has received the selection request, selects a telephone terminal to be used by user operation, and notifies the teleconference server <NUM> of the selected telephone terminal (step S31). When the in-house telephone terminal <NUM> is selected, the same processing as in steps S17 to S22 in <FIG> may be executed. In this example, it is assumed that the mobile telephone terminal <NUM> is selected.

The participation processing unit <NUM> of the teleconference server <NUM> refers to the association table <NUM> of the storage unit <NUM>, acquires information of the selected telephone terminal, and transmits the information of the telephone terminal to the PBX 30c via the Internet <NUM> (step S32). The information of the telephone terminal includes terminal type information of the telephone terminal. In the present example, the information of the telephone terminal includes that the terminal type is a mobile telephone and a mobile telephone number of the mobile telephone terminal <NUM>. This allows the PBX 30c to smoothly determine the line.

Then, the call making unit <NUM> of the PBX 30c determines to make a call using an external line, i.e., PSTN <NUM>, from the terminal type information, uses the telephone number of the mobile telephone terminal <NUM>, and makes a call to the mobile telephone terminal <NUM> by using the PSTN <NUM> (step S33).

The mobile telephone terminal <NUM> responds to the call by user operation (step S34).

The call relay unit <NUM> of the PBX 30c, which has received the response, connects a call path between the teleconference server <NUM> and the mobile telephone terminal <NUM> (step S35). As a result, the call relay unit <NUM> starts to relay the audio call between the teleconference server <NUM> and the mobile telephone terminal <NUM> via the PSTN <NUM> (step S36).

<FIG> is a diagram illustrating an example of display of the communication terminal <NUM> according to the fourth example embodiment. A display unit (not illustrated) of the communication terminal <NUM> receives a participation preparation notification and a terminal selection request from the teleconference server <NUM>, and displays a screen as illustrated in the figure.

For example, a display screen of a teleconference application (Web conference application) in which a pop-up display for prompting switching of a terminal to be used for an audio call is displayed is illustrated in the figure. When the user selects a telephone terminal of a switching destination among the displayed telephone terminals, the selected telephone terminal is called from the PBX 30c. Note that the audio output of the communication terminal <NUM> may be muted or the audio call may be disconnected in response to the user selecting the telephone terminal of the switching destination.

As described above, according to the fourth example embodiment, the teleconference system 1c can deal with various telephone terminals while achieving the same effects as those of the second example embodiment. In addition, since the user continues the audio call via the PBX 30c, even when an external line is used, the call charge can be borne by an organization. For example, even when a user participates in a teleconference at a personal mobile terminal from outside his/her company by telework or the like, the call charge can be borne by the company.

Note that the present disclosure is not limited to the above-described example embodiments, and can be appropriately modified without departing from the spirit thereof.

Although the present disclosure has been explained as a hardware configuration in the above-described example embodiments, the present disclosure is not limited thereto. The present disclosure can also achieve various processing related to the telephone relay method by causing a processor to execute a computer program.

<FIG> is a hardware configuration diagram of a computer <NUM> according to the first to fourth example embodiments.

The computer <NUM> includes a processor <NUM>, a Read Only Memory <NUM> (ROM), a Random Access Memory <NUM> (RAM), and an Interface unit <NUM> (IF). The processor <NUM>, the ROM <NUM>, the RAM <NUM>, and the interface unit <NUM> are connected to each other via a data bus or the like.

The processor <NUM> has a function as an arithmetic device that performs control processing, arithmetic processing, and the like. The processor <NUM> may be a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a field-programmable gate array (FPGA), a digital signal processor (DSP), or an application specific integrated circuit (ASIC), and combinations thereof. The ROM <NUM> has a function for storing a control program, an arithmetic program, and the like that are executed by the processor <NUM>. The RAM <NUM> has a function for temporarily storing processing data and the like. The interface unit <NUM> inputs and outputs a signal to and from the outside via a wire or wirelessly. In addition, the interface unit <NUM> receives an operation of inputting data by the user, and displays information to the user. For example, the interface unit <NUM> of the teleconference server <NUM> communicates with the interface unit <NUM> of the communication terminal <NUM> and the interface unit <NUM> of the PBX 30a.

In the examples described above, the program, when loaded into a computer, includes an instruction group (or software code) to cause a computer to perform one or more of the functions described in the example embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example, and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory techniques, CD-ROM, digital versatile disc (DVD), Blu-ray (registered trademark) disk or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage, or other magnetic storage devices. The program may be transmitted on a transitory computer readable medium or a communication medium. By way of example, and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

In the above-described example embodiments, the computer <NUM> includes a computer system including a personal computer, a word processor, and the like. However, the present invention is not limited thereto, and the computer may be constituted by a server of a local area network (LAN), a host of computer (personal computer) communication, a computer system connected to the Internet, or the like. In addition, it is also possible to distribute functions among devices on a network and configure a computer over the entire network.

Although the present invention has been explained with reference to the example embodiments, the present invention is not limited to the above. Various modifications that can be understood by a person skilled in the art within the scope of the invention can be made to the configuration and details of the present invention.

Claim 1:
A telephone relay device (<NUM>) being communicably connected to a teleconference server (<NUM>) configured to relay an audio call between communication terminals (<NUM>) participating in a teleconference via an Internet Protocol IP network (<NUM>), the telephone relay device (<NUM>) comprising:
a participation request unit (<NUM>) configured to request the teleconference server (<NUM>) 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 (<NUM>) becomes less than a predetermined level, from the teleconference server (<NUM>);
a call making unit (<NUM>) configured to make a call to a telephone terminal (<NUM>, <NUM>) associated with the communication terminal (<NUM>) in response to being permitted to participate in the teleconference; and
a call relay unit (<NUM>) configured to relay an audio call of the teleconference between the telephone terminal (<NUM>, <NUM>) and the teleconference server (<NUM>) in response to receiving a response to the call from the telephone terminal (<NUM>, <NUM>).