JP7736348B1 - PBX system, PBX, common function providing device, PBX function providing method, and PBX function providing program - Google Patents

Abstract

In a hybrid system having multiple PBXs, the burden on a user who uses duplicated functions in both of the multiple PBXs is reduced.
[Solution] The PBX system of an embodiment comprises a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, and the first PBX and the second PBX respectively store the VM box extension number of the first PBX and the VM box extension number of the second PBX that correspond to a user in advance, and when a voice message is stored in the first VM box, the first PBX makes a call from the VM box extension number of the first PBX that corresponds to the user of the voice message to the VM box extension number of the second PBX, and when the second VM box answers, it sends VM information including at least the voice message.
[Selected Figure] Figure 5A

Description

This disclosure relates to a PBX system, a PBX, a common function providing device, a PBX function providing method, and a PBX function providing program.

Private branch exchanges (PBXs) have long been widely used, accommodating internal line terminals and connecting incoming calls from external line terminals to internal line terminals used within a company, as well as connecting internal lines to each other. Cloud PBXs, which use the Internet to enable mobile devices such as smartphones carried by company employees and other users to be used as internal line terminals, are also becoming widely used, connecting incoming calls from external line terminals to the users' mobile devices and connecting the users' mobile devices to each other. PBX linkage systems, which integrate a conventional PBX and a cloud PBX, are also known, and are sometimes referred to as hybrid systems (Patent Document 1).

PBXs equipped with voicemail functions are also widely used. With voicemail, for example, when an internal terminal receives a call, the PBX can answer the call on behalf of the called internal terminal and record a voice message from the caller. Furthermore, with voicemail, for example, the PBX can play back the recorded message from the caller in response to a specific user operation on the called internal terminal, allowing the user to listen to the voice message. In addition to voicemail, PBXs generally have a variety of other functions that can be provided to users, such as a conference communication function that connects three or more terminal devices for communication and allows three or more users to talk simultaneously.

Japanese Patent Application Laid-Open No. 2023-179124

The disclosures of the above-mentioned prior art documents are incorporated herein by reference. The following analysis was conducted by the inventors.

As mentioned above, the PBX and Cloud PBX each have various functions, but in a hybrid system, there may be overlap between the functions provided by the PBX and the functions provided by the Cloud PBX. As such, in a hybrid system, it is necessary to divide the functions so that the processing for overlapping functions is performed by either the PBX or the Cloud PBX. In accordance with this division of functions, for example, one of the PBX and Cloud PBX in a hybrid system is configured to perform overlapping functions, and the other is configured not to perform overlapping functions.

For example, if a user wants to use an overlapping function according to this functional division, they must understand which functions are implemented through processing by the PBX and which functions are implemented through processing by the cloud PBX, and then select and use one of them. This places a significant burden on the user when operating an extension terminal to use an overlapping function. Furthermore, even if both the PBX and the cloud PBX have the same type of function, the specifications for the same type of function on each PBX may differ, which further increases the burden on the user to use one of the desired overlapping functions.

In light of the above-mentioned issues, the purpose of this disclosure is to help reduce the burden on users who attempt to use overlapping functions in both PBX and cloud PBX in a hybrid system.

In a first aspect of the present disclosure, there is provided a PBX system comprising a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, wherein the first PBX and the second PBX respectively store a VM box extension number of the first PBX and a VM box extension number of the second PBX that correspond to a user in advance, and the first PBX is configured to, when a voice message is stored in the first VM box, make a call from the VM box extension number of the first PBX that corresponds to the user of the voice message to the VM box extension number of the second PBX, and, when the second VM box answers, transmit VM information including at least the voice message.

In a second aspect of the present disclosure, there is provided a PBX that includes a VM box, stores a PBX VM box extension number and a second VM box extension number that correspond to a user in advance, and is configured to, when a voice message is stored in the VM box, make a call from the PBX VM box extension number that corresponds to the user of the voice message to the second VM box extension number, and, when the second VM box answers, transmit VM information including at least the voice message.

In a third aspect of the present disclosure, there is provided a common function providing device for a PBX that provides a common function common to a PBX and another PBX other than the PBX, the common function providing device transmitting function information used for the requested common function to the other PBX when a first terminal device that can communicate with at least one of the PBX and the other PBX requests provision of the common function;
A common function providing device is provided that is configured to transmit the function information received from the other PBX to a second terminal device that can communicate with at least one of the PBX and the other PBX when the provision of the common function is requested by the second terminal device.

In a fourth aspect of the present disclosure, there is provided a method for providing PBX functions in a PBX system including a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, the method including the steps of: the first PBX and the second PBX respectively storing a VM box extension number of the first PBX and a VM box extension number of the second PBX that correspond to a user in advance; and the first PBX, when a voice message is stored in the first VM box, making a call from the VM box extension number of the first PBX that corresponds to the user of the voice message to the VM box extension number of the second PBX, and when the second VM box answers, transmitting VM information including at least the voice message.

In a fifth aspect of the present disclosure, there is provided a PBX function providing program that provides functions in a PBX having a PBX and a VM box connected to the PBX, wherein at least the PBX has one or more processors, the PBX has a process for storing a PBX VM box extension number and a second VM box extension number that correspond to a user in advance, and the PBX has a processor that causes the PBX to execute a process for, when a voice message is stored in the VM box, calling the second VM box extension number from the PBX VM box extension number that corresponds to the user of the voice message, and when the second VM box responds, sending VM information including at least the voice message.
The program may be recorded on a computer-readable storage medium. The storage medium may be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present disclosure may be embodied as a computer program product.

Each aspect of this disclosure can help reduce the burden on users who attempt to use overlapping functions in both PBX and cloud PBX in a hybrid system.

FIG. 1A illustrates one aspect of a voice message function provided by a cloud PBX to a user UX of a terminal device and an extension user UI of one of the terminal devices in one configuration of a hybrid system. Figure 1B is a diagram illustrating an example of a communication sequence when an outside terminal device makes a call to an inside terminal device, and a user UX of the outside terminal device and a user UI of the inside terminal device use a VM function provided by a VM box of a cloud PBX. FIG. 2A is a diagram illustrating an example of a manner in which a private branch exchange provides a VM function to a user UX of an external terminal device and a user UI of an internal terminal device in the hybrid system shown in FIG. 1A. FIG. 2B illustrates an example of a communication sequence when an outside terminal device makes a call to an inside terminal device, and a user UX of the outside terminal device and a user UI of the inside terminal device use a VM function provided by a VM box of a private branch exchange. FIG. 3A is a diagram illustrating one configuration of a hybrid system. FIG. 3B is a diagram illustrating one configuration of the cloud PBX and private branch exchange shown in FIG. 3A. FIG. 3C is a diagram showing the correspondence between the components of the first aspect of the present disclosure and the components of the hybrid system shown in FIG. 3A. FIG. 3D is a diagram illustrating an example of a hardware configuration of the communication control device of the cloud PBX and the private branch exchange shown in FIG. 3B. FIG. 4A is a diagram illustrating communication connection information used for communication connection between a cloud PBX and a terminal device stored in a database device of a private branch exchange. FIG. 4B is a diagram illustrating VM information required for providing a VM function by a VM box stored in a database device of the cloud PBX. FIG. 4C is a diagram illustrating VM information stored in the database device of the private branch exchange, which is required for the VM box of the private branch exchange to provide a VM function. Figure 5A is a diagram illustrating the operation of a hybrid system in which a VM box in a cloud PBX records a voice message from a terminal device on the outside line, generates transcription information, and transmits the VM information and transcription information to one of the terminal devices on the inside line. FIG. 5B is a communication sequence diagram illustrating an operation of the hybrid system illustrated in FIG. 5A. FIG. 5C is a communication sequence diagram illustrating another operation of the hybrid system illustrated in FIG. 5A. Figure 6A is a diagram illustrating the operation of a hybrid system in which a VM box in a private branch exchange records a voice message from a terminal device on the outside line, a VM box in a cloud PBX generates transcription information, and sends the VM information and transcription information to one of the terminal devices on the inside line. FIG. 6B is a communication sequence diagram illustrating an operation of the hybrid system illustrated in FIG. 6A. FIG. 6C is a communication sequence diagram illustrating another operation of the hybrid system illustrated in FIG. 6A.

Embodiments of the present disclosure will be described below with reference to the drawings. However, the present disclosure is not limited to the embodiments described below. Furthermore, in each drawing, identical or corresponding elements are appropriately designated by the same reference numerals, and identical or corresponding processes and communications are also appropriately designated by the same reference numerals. Furthermore, it should be noted that the drawings are schematic. Furthermore, connecting lines between blocks in the drawings, etc. referenced in the following description include both bidirectional and unidirectional lines. Unidirectional arrows schematically indicate the flow of the main signal (data) and do not exclude bidirectionality.

Figure 1A is a diagram illustrating one aspect of the voice message (VM) function provided by the cloud PBX 10 to a user UX of terminal device 304 and an internal user UI (I is an integer greater than or equal to 1) of either terminal device 102 or 104 in one configuration of the hybrid system 1. As shown in Figure 1A, the hybrid system 1 includes a cloud PBX 10 and an internal system 16. The internal system 16 includes a gateway (GW) device 12 and a private branch exchange (PBX) 14. The cloud PBX 10 and the gateway device 12 are connected via a communication line capable of two-way data communication, such as an IP (Internet Protocol) line 126. The gateway device 12 and the private branch exchange 14 are connected via a communication line capable of two-way data communication, such as an IP line 120.

Terminal devices 102, 104 such as smartphones and PCs (Personal Computers) are connected to the extension side of the cloud PBX 10, and terminal devices 142 such as multi-function telephones are connected to the extension side of the private branch exchange 14. The private branch exchange 14 is communicatively connected to a communication network such as the Public Switched Telephone Network (PSTN) 30 via one or more communication lines, including analog communication lines such as the PSTN line 300, digital communication lines, wired communication lines such as telephone lines, and wireless lines such as mobile phone communication lines, so as to be able to send and receive voice signals and information bidirectionally. Furthermore, the private branch exchange 14 is communicatively connected to external terminal devices 304 such as smartphones via the PSTN line 300, PSTN line 302, etc. However, instead of the private branch exchange 14, the gateway device 12 may be communicatively connected to the PSTN line 300, or both the cloud PBX 10 and the private branch exchange 14 may be communicatively connected to the PSTN line 300.

The cloud PBX 10 and private branch exchange 14 basically have similar communication functions. The functions of the cloud PBX 10 are realized in a cloud consisting of multiple servers connected to the Internet or other networks, where the PBX functions are performed. The private branch exchange 14 has traditionally been installed on premises such as within a company or building, and has been called a private branch exchange or key telephone. A PBX is located in a communications equipment room or other location on the premises, and is realized by hardware housed in one or more enclosures and software that runs on this hardware.

The gateway device 12 converts the protocol of information output from the cloud PBX 10 to the private branch exchange 14, allowing the private branch exchange 14 to receive information from the cloud PBX 10. The gateway device 12 also converts the protocol of information output from the private branch exchange 14 to the cloud PBX 10, allowing the cloud PBX 10 to receive information from the private branch exchange 14. By connecting the cloud PBX 10 and the private branch exchange 14 with the gateway device 12, the cloud PBX 10 and the private branch exchange 14 operate as if they were a single PBX.

The cloud PBX 10 and private branch exchange 14 establish a communication connection between one or more of the terminal devices 102, 104, 142, and 304 that originate calls to the cloud PBX 10 and private branch exchange 14 and one or more of the terminal devices 102, 104, 142, and 304 that are the destinations of calls, enabling the transmission and reception of voice signals and data communication. The cloud PBX 10 and private branch exchange 14 also provide the terminal devices 102, 104, 142, and 304 and their users with functions related to communication between the terminal devices 102, 104, 142, and 304, such as VM functions and conference communication functions.

The communication functions include unique functions that can only be provided by either the cloud PBX 10 or the private branch exchange 14, and common functions that can be provided by both the cloud PBX 10 and the private branch exchange 14. For the sake of concreteness and clarity, the following explanation will be exemplified by a case in which the cloud PBX 10 and the private branch exchange 14 provide a voice message (VM) function as a common function.

The cloud PBX 10 includes a VM box 100 that implements VM functions, and the private branch exchange 14 includes a VM box 140 that also implements VM functions. The VM boxes 100 and 140 can be implemented in the cloud PBX 10 and the private branch exchange 14, respectively, as trunks connected to switches used for communication connections between terminals, using dedicated hardware, or a combination of hardware and programs executed on this hardware. Alternatively, the VM boxes 100 and 140 can be implemented in software through the processing of programs executed by processors included in the cloud PBX 10 and the private branch exchange 14.

The VM function includes, for example, when an external call is made from an external terminal device 304 to an internal terminal device 102, the cloud PBX 10 and the private branch exchange 14 record the caller's voice message in response to the caller's operation on the terminal device 304. Furthermore, the VM function includes playing back the caller's voice message and letting the user hear it in response to the user's operation on the destination terminal device 102.

Next, the operation of the hybrid system 1 will be described, as shown by the dotted line in Figure 1A, by the cloud PBX 10 providing the VM function to user UX of the originating terminal device 304 and user UI of either of the destination terminal devices 102, 104 using the VM box 100. Note that, as indicated by the symbol X in Figure 1A, at this time, users UX and UI are not provided with the VM function of the private branch exchange 14. Also, while Figure 1A shows a case in which the cloud PBX 10 accommodates two terminal devices 102 and 104, to avoid complicating the explanation, a specific example will be given in which terminal device 304 makes a call to terminal device 102 and these users UX and UI are provided with the VM function.

Figure 1B is a diagram illustrating an example of a communication sequence when an external terminal device 304 makes a call to an internal terminal device 102, and the user UX of the external terminal device 304 and the user UI of the internal terminal device 102 use the VM function provided by the VM box 100 of the cloud PBX 10. Note that in Figure 1B, "Cloud PBX" may actually mean "Cloud PBX 10 and VM box 100."

As shown in FIG. 1B, in S100, user UX operates terminal device 304 (terminal UX) on the outside line side to make a call to terminal device 102 accommodated in cloud PBX 10 as the destination. In S102, terminal device 304 transmits call information indicating the caller's telephone number of terminal device 304 and the extension number of terminal device 102 to cloud PBX 10 via private branch exchange 14 and gateway device 12. Note that in the following descriptions regarding FIGS. 1B and 2B, the phrase "via private branch exchange 14 and gateway device 12" will be omitted. In S104, cloud PBX 10 processes the call information received from terminal device 304 and performs call reception processing to have the call from terminal device 304 arrive at terminal device 102 (terminal UI) used by the destination user UI.

In S106, if the VM function is set on either the destination terminal device 102, 104, the cloud PBX 10 performs processing for a VM response, such as informing the user UX using the terminal device 304 of this by voice or other means. In S108, the cloud PBX 10 transmits a VM response voice to the terminal device 304 indicating that the VM function is available. In S110, upon hearing the VM response voice, the user UX performs an operation on the terminal device 304 to use the VM function. In S112, the terminal device 304 transmits operation information indicating the operation of the user UX to the cloud PBX 10. Note that S110 and S112 may be omitted.

At S114, in order to provide the VM function, the cloud PBX 10 performs processing for a recording response, prompting the user UX to input a voice message into the terminal device 304 and outputting a recording start guide voice to the terminal device 304 indicating that a voice message will be recorded. At S116, the cloud PBX 10 transmits the recording start guide voice to the terminal device 304, which outputs it to the user UX. At S118, upon hearing the recording start guide voice, the user UX inputs a voice message into the terminal device 304, and the terminal device 304 sequentially transmits VM information indicating the input voice message to the cloud PBX 10.

In S120, the cloud PBX 10 sequentially receives and records voice messages from the terminal device 304. In S122, when user UX finishes inputting VM information, processing for terminating the call is performed between the cloud PBX 10 and the terminal device 304, such as disconnecting the communication connection between them. In S124, the cloud PBX 10 transmits VM display information to the display device of the terminal device 102 to display that there is a voice message from user UX to user UI. The display on the display device of the terminal device 102 is performed, for example, by an LED or a display. The display device of the terminal device 102 receives the VM display information and displays to user UI that there is a voice message from user UX to user UI.

In S126, when the user UI of the terminal device 102 sees the display indicating that there is a voice message, the user UI performs an operation on the terminal device 102 to make a call to the cloud PBX 10. Furthermore, the user UI performs an operation on the terminal device 102 to listen to the voice message of user UX recorded using the VM function. Note that between the processing of S124 and the processing of S126, some time may pass between the display on the user UI indicating that there is a voice message and the user UI noticing this display and performing an operation to listen to the voice message. In S128, the terminal device 102 accepts the operation of the user UI and transmits operation information indicating the accepted operation to the cloud PBX 10.

At S130, the cloud PBX 10 performs processing to make a VM response indicating that a playback start guide audio indicating that playback of the recorded voice message of user UX will begin will be output from the terminal device 102. At S132, the cloud PBX 10 transmits the playback start guide audio to the terminal device 102, causing it to be output to the user UI. At S134, the user UI performs an operation on the terminal device 102 to play back the recorded voice message of UX. At S136, the terminal device 102 transmits operation information indicating the user's operation to the cloud PBX 10.

In S138, the cloud PBX 10 receives operation information from the terminal device 102 and performs processing to sequentially play back voice messages from user UX to user UI. In S140, the cloud PBX 10 transmits the played back voice messages from user UX to the terminal device 102, which outputs them to the user UI.

In S142, when playback of user UX's voice message has finished, cloud PBX 10 performs processing to notify the user UI that playback of the voice message has finished. In S144, cloud PBX 10 notifies the user UI that playback of the voice message has finished, and transmits an end notification voice to the terminal device 102 requesting further operation. In S146, processing to end the call is performed, such as disconnecting the communication connection between cloud PBX 10 and terminal device 102.

Next, the operation of the hybrid system 1 will be described, as shown by the dotted line in Figure 2A, by which the private branch exchange 14 uses the VM box 140 to provide the VM function to user UX of the originating terminal device 304 and user UI of the destination terminal device 142. Figure 2A is a diagram illustrating one mode in which the private branch exchange 14 provides the VM function to user UX of terminal device 304 and user UI of terminal device 142 in the hybrid system 1 shown in Figure 1A. Note that, as indicated by the symbol X in Figure 2A, users UX and UI are not provided with the VM function of the cloud PBX 10 at this time.

Figure 2B is a diagram illustrating an example of a communication sequence when an outside terminal device 304 makes a call to an internal terminal device 142, and user UX of the outside terminal device 304 and user UI of the internal terminal device 142 use the VM function provided by the VM box 140 of the private branch exchange 14. Note that in Figure 2B, "private branch exchange" may actually mean "private branch exchange 14 and VM box 140." Note that the communication sequence shown in Figure 2B is similar to the communication sequence shown in Figure 1A, although the entities performing the communication and processing are different.

As shown in FIG. 2B, in S160, user UX operates terminal device 304 (terminal UX) on the outside line side to make a call to terminal device 142 accommodated in private branch exchange 14 as the destination. In S162, terminal device 304 transmits call information indicating the caller's telephone number of terminal device 304 and the extension number of terminal device 142 to private branch exchange 14. In S164, private branch exchange 14 processes the call information received from terminal device 304 and performs call reception processing to have the call from terminal device 304 arrive at terminal device 142 (terminal UI) used by the destination user UI.

In S166, if the VM function is set in the destination terminal device 142, the private branch exchange 14 performs processing for a VM response, such as informing the user UX using the terminal device 304 of this fact by voice or other means. In S168, the private branch exchange 14 transmits a VM response voice to the terminal device 304 indicating that the VM function is available. In S170, upon hearing the VM response voice, the user UX performs an operation on the terminal device 304 to use the VM function. In S172, the terminal device 304 transmits operation information indicating the operation of the user UX to the private branch exchange 14. Note that the processing of S170 and S172 may be omitted.

At S174, in order to provide the VM function, the private branch exchange 14 performs processing for a recording response, prompting the user UX to input a voice message into the terminal device 304 and outputting a recording start guide voice to the terminal device 304 indicating that a voice message will be recorded. At S176, the private branch exchange 14 transmits the recording start guide voice to the terminal device 304, which outputs it to the user UX. At S178, upon hearing the recording start guide voice, the user UX inputs a voice message into the terminal device 304, and the terminal device 304 sequentially transmits VM information indicating the input voice message to the private branch exchange 14.

In S180, the private branch exchange 14 sequentially receives and records voice messages from the terminal device 304. In S182, when user UX finishes inputting VM information, processing for terminating the call is performed between the private branch exchange 14 and the terminal device 304, such as disconnecting the communication connection between them. In S184, the private branch exchange 14 transmits VM display information to the display device of the terminal device 142 to display that there is a voice message from user UX to user UI. The display device of the terminal device 142 receives the VM display information and displays to user UI that there is a voice message from user UX to user UI.

In S186, when the user UI of the terminal device 142 sees the display indicating that there is a voice message, the user UI performs an operation on the terminal device 142 to make a call to the private branch exchange 14. Furthermore, the user UI performs an operation on the terminal device 142 to listen to the voice message of user UX recorded using the VM function. Between the processing of S184 and the processing of S186, some time may pass between the display on the user UI indicating that there is a voice message and the user UI noticing this display and performing an operation to listen to the voice message. In S188, the terminal device 142 accepts the operation of the user UI and transmits operation information indicating the accepted operation to the private branch exchange 14.

At S190, the private branch exchange 14 performs processing to issue a VM response indicating that a playback start guide voice indicating that playback of the recorded voice message of user UX will begin will be output from the terminal device 142. At S192, the private branch exchange 14 transmits the playback start guide voice to the terminal device 142, causing it to be output to the user UI. At S194, the user UI performs an operation on the terminal device 142 to play back the recorded voice message of UX. At S196, the terminal device 142 transmits operation information indicating the user's operation to the private branch exchange 14.

In S198, the private branch exchange 14 receives operation information from the terminal device 142 and performs processing to sequentially play back voice messages from user UX to user UI. In S200, the private branch exchange 14 transmits the played back voice messages from user UX to the terminal device 142, which outputs them to user UI.

In S202, when playback of user UX's voice message has finished, the private branch exchange 14 performs processing to notify the user UI that playback of the voice message has finished. In S204, the private branch exchange 14 notifies the user UI that playback of the voice message has finished, and transmits an end notification voice to the terminal device 142 requesting further operation. In S206, processing to end the call is performed, such as disconnecting the communication connection between the private branch exchange 14 and the terminal device 142.

[Embodiment]
An embodiment of the present disclosure will be described below with reference to Figures 3A to 6B. Figure 3A is a diagram illustrating an example configuration of a hybrid system 2. As shown in Figure 3A, the hybrid system 2 includes components similar to those of the hybrid system 1 shown in Figure 1A and other figures. However, in the hybrid system 1, the cloud PBX 10 is replaced with a cloud PBX 20 that operates differently from the cloud PBX 10, and the private branch exchange 14 is replaced with a private branch exchange 22 that operates differently from the private branch exchange 14. Note that while "PBX" and "private branch exchange" have the same meaning, the reason for separating the terms "private branch exchange 22" and "cloud PBX 20" is to avoid confusion.

Figure 3B is a diagram illustrating one configuration of the cloud PBX 20 and private branch exchange 22 shown in Figure 3A. As shown in Figure 3B, the cloud PBX 20 includes a communication control device 24, a VM box 200, a call control device 202, and a database device 204 (DB; Data Base), each connected to the communication control device 24. These components of the cloud PBX 20 are distributed and implemented in the cloud. The private branch exchange 22 also includes a communication control device 24, a VM box 220, a call control device 202, and a database device 204, each connected to the communication control device 24. These components of the private branch exchange 22 are implemented by a combination of hardware housed in one or more enclosures on the premises and software executed on the hardware. These components enable the hybrid system 2 to allow a user UI, such as terminal device 102, and a user UX of terminal device 304 to use both the VM box 200 of the cloud PBX 20 and the VM box 220 of the private branch exchange 22.

In addition to recording the voice message in the process of S120 shown in FIG. 1B, the VM box 200 also has the function of recognizing the voice message and transcribing the contents of the voice message. Furthermore, in the process of S124, the VM box 200 includes the contents of the voice message transcribed in the process of S120 in the VM display information and displays it on a display device such as the terminal device 102. On the other hand, the VM box 220 does not perform such transcription.

Figure 3C is a diagram showing the correspondence between the components of the first perspective of the present disclosure and the components of the hybrid system 2 shown in Figure 3A. As shown in Figure 3C, the first PBX of the first perspective corresponds to the private branch exchange 22, and the second PBX of the first perspective corresponds to the cloud PBX 20. The first VM box of the first perspective corresponds to the VM box 220.

Figure 3D is a diagram illustrating one example of the hardware configuration of the communication control device 24 of the cloud PBX 20 and private branch exchange 22 shown in Figure 3B. As shown in Figure 3D, the communication control device 24 includes a CPU (Central Processing Unit) 240, a main memory device 242, an auxiliary memory device 244, and an interface (IF) circuit 246. The communication control device 24 controls the call control device 202 and VM box 220 and manages the information stored in the database device 204 using the components of the information processing device (computer) shown in Figure 3D.

The communication control device 24 performs processes such as communication connections for voice calls and data communications between internal terminal devices 102, 104, and 142, communication connections for voice calls and data communications between terminal devices 102, 104, and 142 and external terminal device 304, and processing for providing communication-related services such as VM functions and conference call functions to the user UI and UX in cooperation with the cloud PBX 20 and private branch exchange 22. However, Figure 3D is an example of the hardware configuration of the communication control device 24 and is not limiting. Furthermore, the communication control device 24 may include components not shown in Figure 3D.

The CPU 240 executes numerous instructions contained in a program (not shown) for implementing the communication connections for voice calls and data communications executed by the communication control device 24, and the communication-related services provided to the user UI and UX by the cloud PBX 20 and private branch exchange 22 in cooperation with each other. The main memory device 242 includes storage devices such as RAM (Random Access Memory) and ROM (Read Only Memory), and temporarily stores the programs executed by the CPU 240 and data used to execute these programs.

The auxiliary storage device 244 includes, for example, a non-volatile storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or flash memory, and stores programs executed by the CPU 240 and data used to execute these programs on a medium- to long-term basis. The programs executed by the CPU 240 may be provided as a program product recorded on a non-transitory computer-readable storage medium. The CPU 240 and interface circuit 246 input and output information required for communication connections for voice calls and data communications and for services associated with such communications between the call control device 202, database device 204, and VM boxes 200 and 220.

Under the control of the communication control device 24, the call control device 202 establishes communication connections between the internal terminal devices 102, 104, and 142, or between the terminal devices 102, 104, and 142 and the external terminal device 304, to enable voice calls and data communications.Under the control of the communication control device 24, the VM boxes 200 and 220 perform processing to provide VM functions similar to those of the VM boxes 100 and 140 (e.g., Figure 1A) as common functions to the user UI and UX.

The database device 204 stores information required for processing by the communication control device 24 in table format in the main memory device 242 and/or the auxiliary memory device 244. The information stored in the database device 204 includes information required for communication connections between the terminal devices 102, 104, 142, and 304, information required for unique functions that the cloud PBX 20 or private branch exchange 22 independently provides to the user UI and UX, and information required to provide unique and common functions to the user UI and UX.

Next, with reference to Figures 4A to 4C, the information stored in the database device 204 and used for processing by the communication control device 24 will be described. Figure 4A is a diagram illustrating communication connection information used for communication connections between terminal devices 102, 104, 142, and 304, stored in the database device 204 of the cloud PBX 20 and the private branch exchange 22. Figure 4B is a diagram illustrating VM information stored in the database device 204 of the cloud PBX 20, which is required for the VM box 200 to provide VM functions. Figure 4C is a diagram illustrating VM information stored in the database device 204 of the private branch exchange 22, which is required for the VM box 220 of the private branch exchange 22 to provide VM functions.

As shown in FIG. 4A, the communication connection information includes, in a table format, the user UIs (U1, U2, etc.) of the hybrid system 2, the extension numbers (AAA, BBB, etc.) of the internal terminal devices 102, 104, 142 used by each user UI, the corresponding outside numbers (IIII-JJJJ-KKKK, etc.) associated with the extension numbers, the extension numbers (AAA', BBB', etc.) of the VM box 200, and the extension numbers (AAA", BBB", etc.) of the VM box 220. The communication connection information shown in FIG. 4A is stored in common content in both the cloud PBX 20 and the database device 204 of the private branch exchange 22.

The extension number of the VM box 200 is used to access the functions of the VM box 200 of the cloud PBX 20. The extension number of the private branch exchange 22 is used to access the functions of the VM box 220 of the private branch exchange 22. Furthermore, when the user UI makes a call (establishes a communication connection) from one of the internal terminal devices 102, 104, or 142 to the external terminal device 304, the external number associated with one of the terminal devices 102, 104, or 142 is used as the caller's telephone number. Furthermore, when the user UX makes a call (establishes a communication connection) to the hybrid system 2 using the external number from the external terminal device 304, the call from the terminal device 304 to the hybrid system 2 is connected to one of the terminal devices 102, 104, or 142 with the extension number associated with the external number.

As shown in FIG. 4B, the VM information in the VM box 200 includes the extension telephone numbers (AAA', BBB'...) of the VM box 200, the outside line number of the terminal device 304 on the outside line side, VM information (VM1, VM2...), transcription information (TXT1, TXT2...), and message numbers (M1, M2...), all associated in a table format. These are the outside line numbers used when a call was made (communication connection was made) to the hybrid system 2 from the outside line number of the terminal device 304 on the outside line side. The VM information is information indicating a voice message recorded by the user UX using the VM function. The transcription information (TXT1, TXT2...) is text information obtained by the VM box 200 of the cloud PBX 20 transcribing the VM information.

As shown in FIG. 4C, the VM information in VM box 220 includes the VM box 200's extension telephone numbers (AAA', BBB'...), the outside line number of the external line terminal device 304, VM information (VM1, VM2...), transcription information (TXT1, TXT2...), and message numbers (M1, M2...), all associated in a table format. Note that the VM information in cloud PBX 20 and the VM information in private branch exchange 22 share the same information except for the VM box 200's extension telephone numbers and the VM box 220's extension telephone numbers. Also, in FIGS. 4B and 4C, corresponding information is assigned the same message number, and the message number is used to synchronize the VM information.

For example, a message number with a value of 0 indicates that the VM information corresponding to this message number should be deleted. Furthermore, since the VM information in the VM box 220 includes VM information and transcription information, the user UI can access the transcription information from the terminal device 142 housed in the private branch exchange 22.

Next, the operation of the hybrid system 2 will be described when user UX calls (communicates with) the VM box 200 of the PBX 20 from terminal device 304, and user UI listens to the voice message using one of terminal devices 102, 104, or 142. Figure 5A is a diagram illustrating an example of the operation of the hybrid system 2 in which the VM box 200 of the cloud PBX 20 records the voice message from terminal device 304, generates transcription information, and transmits the VM information and transcription information to one of terminal devices 102, 104, or 142. Figure 5B is a communication sequence diagram illustrating an example of the operation of the hybrid system 2 illustrated in Figure 5A. Note that, for the sake of concreteness and clarity, Figure 5B uses the example of transmitting the VM information and transcription information to terminal device 142.

As shown by the dotted line in Figure 5A, user UX first uses, for example, terminal device 304 to call (establish a communication connection with) one of terminal devices 102, 104, or 142 of hybrid system 2, and performs an operation to use the VM function provided by VM box 200 of cloud PBX 20. As shown in Figure 4B, when VM box 200 uses the VM function to store VM information and its transcription information in database device 204, VM box 200 uses VM box 220 of private branch exchange 22 to store the VM information and its transcription information in database device 204 of private branch exchange 22, as shown in Figure 4C.

This operation allows the caller phone number information, VM information, and transcription information used by VM box 200 to provide the VM function to be shared with the caller phone number information, VM information, and transcription information used by VM box 220 to provide the VM function. Furthermore, this operation allows the user UI and UX to use both the VM function and the transcription function of VM boxes 200 and 220 without being concerned about such specification differences, even if there are differences in the specifications of the common functions provided by VM boxes 200 and 220, such as VM box 200 having a transcription function and VM box 220 not having a transcription function.

In Figures 5B, 5C, 6B, and 6C, "Cloud PBX" refers to Cloud PBX 20 itself and VM Box 200, "Private Branch Exchange" refers to Private Branch Exchange 22 itself and VM Box 220, "Terminal UX" refers to Terminal Device 304, and "Terminal UI" refers to any of Terminal Devices 102, 104, and 142. In the processing quoted from Figures 1B and 2B, "Cloud PBX 10," "PBX 14," and "VM Boxes 100 and 140" are to be read as "Cloud PBX 20," "PBX 22," and "VM Boxes 200 and 220." For clarity and specificity, the explanation of Figures 5A to 5C uses the case where a call is made (communication connection is established) from Terminal Device 304 to Terminal Device 142 as a specific example.

As shown in FIG. 5B, first, the processes S100 to S124 shown in FIG. 1B are performed between the outside line terminal device 304 and the VM box 200 of the cloud PBX 20. However, as described above, in the process of S120, transcription is performed by the VM box 200 of the cloud PBX 20, and transcription information is generated as a result of the transcription. The database device 204 of the cloud PBX 20 stores the VM information and the generated transcription information as shown in FIG. 4B.

At S220, the VM box 200 of the cloud PBX 20 makes a call to the VM box 220 of the private branch exchange 22 using the extension number of the VM box 220 of the private branch exchange 22 (Figure 4A). At S222, the VM box 200 sends the extension number of the VM box 220 and other information to the VM box 220. At S224, the private branch exchange 22 performs processing for an incoming call from the VM box 200 to the VM box 220 using the extension number of the VM box 220 and other information, and establishes a communication connection between the VM box 200 and the VM box 220.

As shown by the dotted lines in FIG. 5B, when minimizing changes from VM box 140 to VM box 220, the processes of S226, S228, and S230 are performed as appropriate. At S226, VM box 220 virtually processes the VM response, as in S166 (FIG. 2B). At S228, VM box 220 virtually transmits a VM response voice to VM box 200, as in S168. At S230, VM box 200 virtually accepts an operation to have VM box 220 record a voice message, as in S170. However, no processing to respond to the virtual VM response voice is actually performed, and the virtual voice message is not actually stored in database device 204.

In S232, the VM box 200 transmits operation information to the VM box 220, as in S172. Note that, when minimizing the change from the VM box 140 to the VM box 220, the processes of S234 and S236 are performed as appropriate, as indicated by the dotted lines in FIG. 5B. In S234, the VM box 220 virtually records a response, as in S174. In S236, the VM box 220 virtually transmits a guidance voice to the VM box 200, as in S176. Note that no processing is actually performed on the virtual guidance voice.

At S238, the VM box 200 plays the VM information received from the terminal device 304 and stored in the database device 204 (Figure 4B) and reads the transcription information. At S240, the VM box 200 transmits the played VM information to the VM box 220 as an analog signal or digital data, and also transmits the transcription information to the VM box 220. At S242, the VM box 220 receives the VM information and transcription information and stores them in the database device 204 (Figure 4C).

The display device of terminal device 142 indicates that there is a voice message from user UX to user UI, and when user UI operates terminal device 142 to listen to user UX's voice message recorded using the VM function, the processing of S184 to S206 shown in FIG. 2B is performed. When VM box 220 plays the voice message, reads the transcription information, and sends it to terminal device 142, in S262, VM box 220 notifies VM box 200 that the playback of VM information and the reading of the transcription information have been completed. In S264, the VM box of the cloud PBX deletes information other than the VM box extension number of the private branch exchange from the VM information shown in FIG. 4C (common function information). In S266, the VM box of the private branch exchange deletes information other than the extension number of the VM box of the cloud PBX from the VM information shown in FIG. 4B.

Next, we will explain the operation of the hybrid system 2 when user UX calls (connects to) the hybrid system 2 from the external terminal device 304 and uses the VM function provided by the VM box 200 of the cloud PBX 20, and when user UI calls (connects to) the hybrid system 2 from the internal terminal device 142 and uses the VM function provided by the VM box 220 of the private branch exchange 22. Figure 5C is a communication sequence diagram illustrating another operation of the hybrid system 2 illustrated in Figure 5A.

As shown in FIG. 5C, first, the processes S100 to S124 shown in FIG. 1B are performed between the outside line terminal device 304 and the VM box 200 of the cloud PBX 20. However, as described above, in the process of S120, transcription is performed by the VM box 200 of the cloud PBX 20, and transcription information is generated as a result of the transcription. The database device 204 of the cloud PBX 20 stores the VM information and the generated transcription information as shown in FIG. 4B.

Next, the processes of S220 to S238 shown in FIG. 5B are performed, and the processes of S184 to S206 shown in FIGS. 2B and 5B are performed. Furthermore, in S280, the VM box 220 notifies the VM box 200 that playback of the VM information and reading of the transcription information has ended. Furthermore, the processes of S264 and S266 shown in FIG. 5B are performed.

Next, we will explain the operation of the hybrid system 2 when user UX calls (communicates with) the VM box 220 of the private branch exchange 22 from terminal device 304, and user UI listens to the voice message using the VM function provided by the VM box 220 using one of terminal devices 102, 104, or 142. Figure 6A is a diagram illustrating an example of the operation of the hybrid system 2 in which the VM box 220 of the private branch exchange 22 records a voice message from the external terminal device 304, generates transcription information using the VM box 200 of the cloud PBX 20, and transmits the VM information and transcription information to one of the internal terminal devices 102, 104, or 142. Figure 6B is a communication sequence diagram illustrating an example of the operation of the hybrid system 2 illustrated in Figure 6A. Note that, for the sake of concreteness and clarity, Figure 6B also uses the example of transmitting the VM information and transcription information to terminal device 142.

As shown by the dotted lines in FIG. 6A, user UX first uses, for example, terminal device 304 to call (establish a communication connection with) one of terminal devices 102, 104, or 142 of hybrid system 2, and performs an operation to use the VM function provided by VM box 220 of private branch exchange 22. As shown in FIG. 4C, when VM box 220 stores VM information in database device 204 using the VM function, VM box 220 transmits the VM information to VM box 220 of private branch exchange 20 for transcription. The transcription information obtained as a result of the transcription is associated with the VM information and stored in database device 204 of cloud PBX 20 and private branch exchange 22, as shown in FIGS. 4B and 4C.

As shown in FIG. 6B, first, the processes of S160 to S182 shown in FIG. 2B are performed between the external line terminal device 304 and the VM box 200 of the cloud PBX 20. In S280, the VM box 220 of the private branch exchange 22 makes a call to the VM box 200 of the cloud PBX 20 using the extension number of the VM box 200 of the cloud PBX 20 (FIG. 4A). In S282, the VM box 220 transmits the extension number of the VM box 200 of the cloud PBX 20 and other information to the VM box 200. In S284, the cloud PBX 20 performs processing for an incoming call from the VM box 220 to the VM box 200 using the extension number of the VM box 200 and other information, and establishes a communication connection between the VM box 200 and the VM box 220.

As indicated by the dotted lines in FIG. 6B, when minimizing changes from VM box 100 to VM box 200, the processes of S286, S288, and S290 are performed as appropriate. In S286, the VM box 200 virtually processes the VM response, as in S106 (FIG. 1B). In S288, the VM box 200 virtually transmits a VM response voice to the VM box 220, as in S108. In S290, the VM box 200 virtually accepts an operation to record a voice message, as in S110. However, no processing is actually performed to respond to the virtual VM response voice, and the virtual voice message is not actually stored in the database device 204.

In S292, the VM box 220 transmits operation information to the VM box 200. Note that, when minimizing the change in operation from the VM box 140 to the VM box 220, the processes of S294 and S296 are performed as appropriate, as indicated by the dotted lines in FIG. 6B. In S294, the VM box 220 virtually records a response, as in S114. In S296, the VM box 220 virtually transmits a guidance voice to the VM box 200, as in S116. Note that no processing is actually performed on the virtual guidance voice.

At S298, the VM box 200 plays the VM information received from the terminal device 304 and stored in the database device 204 (Figure 4B) and reads the transcription information. At S300, the VM box 200 transmits the played VM information to the VM box 220 as an analog signal or digital data, and also transmits the transcription information to the VM box 220. At S302, the VM box 220 receives the VM information and transcription information and stores them in the database device 204 (VM recording; Figure 4C).

In S304, the communication connection between VM Box 200 and VM Box 220 is disconnected, and processing for terminating the call is performed between Cloud PBX 20 and Private Branch Exchange 22. Furthermore, the processing of S186 to S206 shown in FIG. 2B is performed. After VM Box 220 plays the voice message, reads the transcription information, and transmits these to terminal device 142, in S320 VM Box 200 notifies VM Box 220 that the playback of the VM information and the reading of the transcription information have been completed. In S322, VM Box 220 deletes all information other than the VM box extension number of the Cloud PBX from the VM information shown in FIG. 4C. Furthermore, VM Box 200 deletes all information other than the VM box extension number of the Cloud PBX from the VM information shown in FIG. 4B.

Next, we will explain the operation of hybrid system 2 when user UX calls (establishes a communication connection with) the VM box 220 of the private branch exchange 22 from terminal device 304, and user UI uses one of terminal devices 102, 104, or 142 to listen to a voice message using the VM function provided by VM box 200.

Figure 6C is a communication sequence diagram illustrating another operation of the hybrid system 2 illustrated in Figure 6A. For the sake of concreteness and clarity, Figure 6C also uses a specific example in which VM information and transcription information are transmitted to the terminal device 142. As shown in Figure 6C, first, the processes of S160 to S182 shown in Figure 2B are performed. Next, the processes of S280 to S304 shown in Figure 6B are performed, followed by the processes of S124 to S142 shown in Figure 1B, and finally the processes of S320 and S322 shown in Figure 6B are performed.

As described above, according to the hybrid system 2, when the VM function is provided in either the cloud PBX 20 or the private branch exchange 22, the fact that a voice message has been recorded is displayed on the terminal devices housed in both the cloud PBX 20 and the private branch exchange 22. Therefore, both the user UI using the terminal devices 102, 104 housed in the cloud PBX 20 and the user UI using the terminal device 142 housed in the private branch exchange 22 can listen to the recorded voice message. Furthermore, even if only the VM box 200 of the cloud PBX 20 has a special function, such as a transcription function, both users using terminal devices housed in the cloud PBX 20 and users using terminal devices housed in the private branch exchange 22 can use the special function.

Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes.
[Appendix 1]
A PBX system comprising a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, wherein the first PBX and the second PBX respectively store a VM box extension number of the first PBX and a VM box extension number of the second PBX that correspond to a user in advance, and when a voice message is stored in the first VM box, the first PBX makes a call from the VM box extension number of the first PBX that corresponds to the user of the voice message to the VM box extension number of the second PBX, and when the second VM box answers, transmits VM information including at least the voice message.
[Appendix 2]
A PBX system as described in Appendix 1, in which, when VM information stored in a first VM box is deleted, the first PBX requests deletion of the VM information stored in a second VM box via the second PBX, and the second VM box deletes the VM information in response to the request.
[Appendix 3]
The PBX system according to claim 1 or 2, wherein the first PBX is a cloud PBX virtually constructed in the cloud, and the second PBX is a private branch exchange installed on the premises.
[Appendix 4]
A PBX system as described in any one of appendices 1 to 3, wherein the VM information includes the voice message and transcription information generated by the first PBX.
[Appendix 5]
The PBX is provided with a VM box, and is configured to store a VM box extension number of the PBX corresponding to a user and a second VM box extension number in advance, and when a voice message is stored in the VM box, to make a call from the VM box extension number of the PBX corresponding to the user of the voice message to the second VM box extension number, and when the second VM box answers, to transmit VM information including at least the voice message.
[Appendix 6]
A common function providing device for a PBX that provides common functions common to the PBX and other PBXs other than the PBX, configured to, when a first terminal device capable of communicating with the PBX and/or one of the other PBXs requests the provision of the common function, transmit function information to the other PBX to be used for the requested common function, and when a second terminal device capable of communicating with the PBX and/or one of the other PBXs requests the provision of the common function, transmit the function information received from the other PBX to the second terminal device.
[Appendix 7]
A method for providing PBX functions in a PBX system comprising a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, the method comprising the steps of: the first PBX and the second PBX respectively storing a VM box extension number of the first PBX and a VM box extension number of the second PBX that correspond to a user in advance; and the first PBX, when a voice message is stored in the first VM box, calling the VM box extension number of the first PBX that corresponds to the user of the voice message to the VM box extension number of the second PBX, and when the second VM box answers, transmitting VM information including at least the voice message.
[Appendix 8]
A PBX function providing program that provides functions in a PBX having a PBX and a VM box connected to the PBX, wherein at least the PBX has one or more processors, and the PBX causes a processor of the PBX to execute the following processes: a process for storing a PBX VM box extension number and a second VM box extension number that correspond to a user in advance; and a process for, when a voice message is stored in the VM box, the PBX makes a call from the PBX VM box extension number that corresponds to the user of the voice message to the second VM box extension number, and when the second VM box responds, transmits VM information including at least the voice message.
It goes without saying that combinations of the various forms described in the appendix of this disclosure, or any combination of the elements described in each aspect and embodiment (including the non-selection of some elements), can be made at any time by those skilled in the art in accordance with the basic concept of this disclosure.

The disclosures of the above-cited patent documents and other documents are incorporated herein by reference. Modifications and adjustments to the embodiments and examples are possible within the entire scope of this disclosure (including the claims), and based on its basic technical concepts. Furthermore, various combinations and selections (including partial deletions) of the various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible within the entire scope of this disclosure. In other words, this disclosure naturally includes various modifications and alterations that would be possible for a person skilled in the art in accordance with the entire disclosure and technical concepts, including the claims. In particular, the numerical ranges set forth herein should be construed as specifically describing any numerical value or subrange within that range, even if not otherwise specified. Furthermore, the disclosures of the above-cited documents are deemed to be included in the disclosures of this application, in whole or in part, which may be used in combination with the disclosures herein, as necessary, in accordance with the spirit of this disclosure.

1, 2 Hybrid System 10, 20 Cloud PBX
100, 140, 200, 220 VM box 102, 104, 142, 304 Terminal device 12 Gateway device 120, 126 IP line 14, 22 Private branch exchange 16 Private branch system 202 Call control device 204 Database device 24 Communication control device 240 CPU
242 Main memory device 244 Auxiliary memory device 246 Interface circuit 30 PSTN
300, 302 Public telephone lines

Claims (8)

a first PBX, a first VM box in the first PBX, a second PBX, and a second VM box in the second PBX;
the first PBX and the second PBX respectively store a VM box extension number of the first PBX and a VM box extension number of the second PBX corresponding to a user in advance;
A PBX system in which, when a voice message is stored in a first VM box, the first PBX makes a call from a VM box extension number of the first PBX corresponding to the user of the voice message to a VM box extension number of the second PBX, and when the second VM box answers, transmits VM information including at least the voice message. When the VM information stored in the first VM box is deleted, the first PBX requests deletion of the VM information stored in the second VM box via the second PBX;
The PBX system according to claim 1 , wherein the second VM box deletes the VM information in response to the request. The PBX system according to claim 1 , wherein the first PBX is a cloud PBX virtually constructed in a cloud, and the second PBX is a private branch exchange installed on a private premises. The PBX system of claim 1 , wherein the VM information includes the voice message and a transcription generated by the first PBX. Equipped with a VM box,
A VM box extension number and a second VM box extension number of the PBX corresponding to the user are stored in advance;
The PBX is configured to, when a voice message is stored in the VM box, make a call from a VM box extension number of the PBX corresponding to the user of the voice message to the second VM box extension number, and when the second VM box answers, transmit VM information including at least the voice message. A common function providing device for a PBX that provides a common function common to a PBX and another PBX other than the PBX,
When a request for provision of the common function is received from a first terminal device capable of communicating with at least one of the PBX and the other PBX, function information used for the requested common function is transmitted to the other PBX;
A common function providing device configured to, when a second terminal device capable of communicating with at least one of the PBX and the other PBX requests the provision of the common function, transmit the function information received from the other PBX to the second terminal device. A method for providing a PBX function in a PBX system including a first PBX, a first VM box of the first PBX, a second PBX, and a second VM box of the second PBX, the method comprising:
a step in which the first PBX and the second PBX respectively store a VM box extension number of the first PBX and a VM box extension number of the second PBX corresponding to a user in advance;
When a voice message is stored in a first VM box, the first PBX makes a call from a VM box extension number of the first PBX corresponding to the user of the voice message to a VM box extension number of the second PBX, and when the second VM box answers, transmits VM information including at least the voice message;
A method for providing a PBX function, including: A PBX function providing program for providing a function in a PBX having a PBX and a VM box connected to the PBX, wherein at least the PBX has one or more processors;
a process in which the PBX stores a VM box extension number and a second VM box extension number of the PBX corresponding to the user in advance;
A PBX function providing program that causes a processor of the PBX to execute a process in which, when a voice message is stored in the VM box, the PBX makes a call from the VM box extension number of the PBX corresponding to the user of the voice message to the second VM box extension number, and when the second VM box answers, transmits VM information including at least the voice message.