JP2000092208A - Private branch exchange and telephone switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To notify the situation of an opposite communication party without making a caller wait more than necessary even when the opposite communication party demanded by an incoming call is absent. SOLUTION: This exchange 10 houses an extension group A consisting of multifunction telephone sets 18-1 to 18-m connected to plural extensions and a paging device 26 associated previously with the extension group A, holds the opposite communication party in the multifunction telephone set in communication and also calls to an opposite communication party requested by the held opposite party with the paging device. In such a case, when a request for unanswerable state notification is inputted by a prescribed special number operation to the multifunction telephone set after the paging device 26 performs calling, it is notified by message notification from a talkie device 32, tone notification from an unanswerable notification tone generator 34 and message display of a displaying part provided in the multifunction telephone set by a controlling part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing an incoming call when a private line exchange cannot respond to an extension.

[0002]

2. Description of the Related Art Generally, in a private branch exchange (including a key telephone apparatus), an extension group constituted by a plurality of extensions to which terminals such as telephones are connected, and a plurality of office lines associated with the extension groups are provided. When the terminal is accommodated and there is an incoming call from one office line, any terminal included in the extension group associated with the incoming office line can respond.

If at least one terminal in the same extension group is not busy, incoming calls to the office line shared by this extension group will not be busy, and a ringing tone will be sent to the caller.

[0004] However, when only one person can respond to the terminal of the extension group and the person who can respond is busy, or even if there is a person who can answer the incoming call, the caller requested by the caller does not have the other party. If the user is not present, a situation occurs in which the caller is made to wait.

Conventionally, in the case where only one person can answer a terminal of an extension group and the person who can answer the call is busy, a non-reply notification is disclosed in Japanese Patent Laid-Open No. 5-75715. A scheme is being considered.

[0006] According to the non-answering notification system disclosed in Japanese Patent Application Laid-Open No. 5-75715, when a terminal other than the talking terminal cannot answer an incoming call from the central office line in the extension group, the calling terminal does not respond. By performing the operation of sending the unresponsiveness state information, it is possible to connect the talkie sound for notifying the unresponsiveness registered in advance to the station line where the incoming call is received.

[0007]

As described above, Japanese Patent Application Laid-Open No.
In the related art disclosed in Japanese Patent No. 75715, an extension group including a plurality of extensions and a plurality of office lines associated with the extension group are accommodated, and a state in which a response can be made when a call is received from the office line is accommodated. When there is no terminal connected to a certain extension, it is possible to notify the unanswered state to the incoming line, but even if there is a person who can respond to the incoming call, It cannot be used if you are not there.

On the other hand, in the prior art, an extension group composed of a plurality of arbitrary extensions and a paging device associated with the extension group in advance are accommodated, and a call is being made with the extension / external line. A system that can hold a call partner by making a special number operation on a certain extension and make an outgoing connection to a paging device, and call the requested party using a speaker connected to the paging device. There is.

With this system, if the other party who has made a connection request can respond, the other terminal can be used to talk with the other party on hold.

[0010] However, if the other party called by the speaker of the paging device is already busy talking on another phone or cannot answer the held call due to a conference or the like, the call cannot be answered. It is not possible to notify the operator of the paging device that the state is possible.
In this situation, even if the non-response notification method disclosed in Japanese Patent Application Laid-Open No. 5-75715 is used, it is necessary to perform the operation of transmitting the non-response state information in the terminal during the call, so that the response cannot be performed. Can not be notified that it is in a bad state.

For this reason, the operator of the paging device has:
Since the situation of the other party of the connection destination is not known, it is necessary to wait for a while to see the situation, and the caller who is on hold during this time is kept on hold and kept waiting more than necessary.

The present invention has been made in view of such circumstances, and notifies the situation of a call partner without making the caller wait more than necessary even when the call partner requested to receive the call is absent. It is an object of the present invention to provide a private branch exchange capable of performing the following.

[0013]

In order to achieve the above object, a private branch exchange according to a first aspect of the present invention comprises: an extension group constituted by terminals connected to a plurality of extensions; And accommodates a paging device that is previously associated with, and performs a special number operation on a terminal that is in a state of talking to an extension or an outside line to hold a caller and make an outgoing connection to the paging device,
In a private branch exchange configured to call the party requested to be connected by the held party with the paging device, after the page is called by the paging device, a response is made by a predetermined special number operation to a terminal of the extension group. Input means for inputting a request for an impossible status notification, and a state in which a response cannot be made to a terminal called by the paging device when a request for a status notification that cannot be responded is input by the input means. And a notifying means for notifying that

[0014] The terminal to which a request for notification of a state in which a response cannot be made by the input means is input is, for example, a terminal in communication with an extension or an outside line or an idle extension terminal.

The notifying means includes, for example, a non-response notifying tone generating means for generating a predetermined tone signal indicating that it is in a non-responding state, wherein the non-responding notifying tone generating means and the paging device are provided. Is connected to the calling terminal to notify that the terminal cannot respond.

[0016] Alternatively, the notifying means has a voice generating means for generating a predetermined message indicating that it is in a non-replyable state, and the calling is performed by the non-response notifying tone generating means and the paging device. By connecting to the terminal, it is notified by a voice message that the terminal cannot respond.

According to the present invention, when the other party called by the paging device is already in a call with another telephone and cannot respond to the call from the paging device, a hooking + dial operation from the telephone used for the call is performed. When the hand cannot be released during a meeting or the like (during a special number operation) or by a dial operation (special number operation) from a nearby telephone, the paging device operator is notified that it is in an unresponsive state. As a notification method, a notification is made by connecting a talkie device in which a special tone or a voice having a content notifying the fact is recorded.

When the paging device operator performs simple handling (when the telephone is on-hook after the calling operation using the speaker), the talkie on which the voice of the content for notifying the held caller is recorded is recorded. By connecting and notifying the device, the waiting time of the caller is reduced.

To achieve the above object, a second aspect of the present invention is provided.
The telephone exchange method according to the aspect of the present invention is adapted to respond to an incoming call on a vacant first telephone among a plurality of extension telephones, and to suspend the incoming call in response to a predetermined operation on the first telephone. And calling the called party on the paging device, responding to the call on the paging device, responding to a predetermined operation on the second extension telephone, and not responding to the incoming call. The first telephone is notified, and in response to the notification, a predetermined notification is made to the caller.

According to this method, the person who receives the call talks with the caller on the first telephone, determines the person who is requested to connect, puts the call on hold, and simultaneously calls the callee. Call the phone or person with a paging device. If the called party cannot answer the call because it is already on the phone or busy, it performs a predetermined operation. By this operation, the person who first receives the call is notified that the call cannot be answered. Therefore, this person can notify the caller of that fact. Also, an automatic response may be used.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a basic configuration of a private telephone system according to the embodiment. As shown in FIG. 1, the private branch exchange 10 has an office line connected to a communication line network (SW) 13 via office line trunk circuits 14-1 to 14-n, and an extension trunk circuit 16-1 to 16-n. Extension lines (multifunctional telephones 18-1 to 18-m) are connected via m.
A paging device 26 is connected to the communication network 13 via a trunk circuit 24, and a talkie device 32 (voice generating means) is connected via a trunk circuit 30. The communication network 13 further includes a non-response notification tone generator 34 for generating a predetermined tone signal and a hold tone generator 3.
6 is connected.

The control unit 12 performs overall control for operating the private branch exchange 10.
2a is realized by executing various programs stored in the memory 12b. The memory 12b stores, in addition to a program for controlling a response impossible notification, information for determining a process requested from the multi-function telephones 18-1 to 18-m. The control unit 12 determines that a specific operation (hooking + special number operation (details will be described later)) on the multifunctional telephones 18-1 to 18m described later is performed based on information stored in the memory 12b. , Execute a process according to the request indicated by the operation. In the present embodiment, when a request for notification of an unresponsive state is made, an extension called by the paging device 26 using a notification unit (described later) for notifying that the state is an unresponsive state. Has the function of notifying the multi-function telephone.

Under the control of the control unit 12, the communication path network 13 is provided between the office line and the extension, between the extension and the paging device 26, between the extension and the non-response notification tone generation unit 34, and between the office line and the hold tone generation. The connection of the communication path such as between the units 36 is switched.

Office trunk circuits 14-1 to 14-n, extension trunk circuits 16-1 to 16-m, trunk circuit 2
4 and the trunk circuit 30 are interfaces for accommodating communication lines and controlling signal conversion, state monitoring, signal transmission, and the like.

The multi-function telephones 18-1 to 18-m are extension terminals provided with a number of other service functions such as hold, transfer, camp-on, and the like. It is assumed that
When there is an incoming call to a station line previously associated with extension group A, the multi-function telephone 18 included in extension group A
-1 to 18-m can respond.
From the multi-function telephones 18-1 to 18-m, by dialing a predetermined specific number (special number operation),
You can request execution of a specific process according to the number,
For example, when it is not possible to respond to the call from the paging device 26, it is possible to request a status notification that cannot respond by hooking + special number operation. The display unit 2 used to display various information when providing various services including an unresponsive status notification (message display) to the multifunction telephones 18-1 to 18-m.
0-1 to 20-m (display means) are provided for each.

The paging device 26 is for calling by voice from the speaker 28, and is used when there is no call partner requested to receive an incoming call from the office line.
It is used by being connected to another extension (multifunctional telephone). A group B is formed including the paging device 26 and the extension group A, and the paging device 26
Are associated in advance.

The talkie device 32 is for generating a voice such as a message, and the message is recorded in advance. In the present embodiment, it is assumed that a message for notifying that it is in a state in which it cannot respond to an incoming call is recorded. The talkie device 32 is connected to the extension (multifunctional telephone) called by the paging device 26 under the control of the control unit 12.

The non-response notification tone generating unit 34 is for generating a non-response non-response notification tone for notifying that it is in a state of being unable to respond to an incoming call, and is controlled by the control unit 12. The paging device 26 is connected to the called extension (multifunctional telephone).

The hold tone generating section 36 is for generating a hold tone for notifying the hold, and is used when the call from the central office is held for calling the other party. It is connected to the office line reserved by the control of Twelve.

In the private telephone system according to the present embodiment, as a means for notifying that the call from the paging device 26 cannot be answered, a talky message in which a message indicating that the call cannot be answered is registered. The notification from the device 32, the notification of the non-response notification tone generated by the non-response notification tone generation unit 34, the display unit 20- provided in the multifunction telephones 18-1 to 18-m under the control of the control unit 12. A function is provided for displaying a non-response message in 1 to 20-m.

(Embodiment 1) Next, the operation of the private telephone system in the first embodiment will be described with reference to FIG.

As shown in FIG.
Multifunctional telephones 18-1 to 18-1 connected to general extensions capable of responding to incoming calls from office lines via -1 to 14-n
In the group B accommodating the paging device 26 previously associated with 8-m, for example, the line trunk circuit 1
It is assumed that there is an incoming call via 4-1.

When the multi-function telephone 18-1 responds to the incoming call, the office line and the multi-function telephone 18-1 are transmitted via the office trunk circuit 14-1 and the extension trunk circuit 16-1.
The communication path with is connected to make a call (1).

Here, when the multi-function telephone 18-1 requests a hold to call the other party requested by the caller, the control unit 12 sets the central office trunk circuit 14-1 and the hold tone generation unit 36. And connect. Further, when the multi-function telephone 18-1 requests a call, the control unit 12 makes an outgoing connection between the multi-function telephone 18-1 and the paging device 26 via the extension trunk circuit 16-1 and the trunk circuit 24 (3). ).

Thus, the multi-function telephone 18-1 can call the other party by voice from the speaker 28 using the paging device 26.

At this time, the called party is in a call state with the other party of the multi-function telephone 18-2 using the multi-function telephone 18-m (0), and cannot respond to the call from the paging device 26. , The called party performs the following special number operation on the multi-function telephone 18-m to notify the operator of the paging device 26 (the multi-function telephone 18-1) that the call cannot be answered. Can be notified.

First, when a hooking + special number operation is performed on the multi-function telephone 18-m by the called party, the multi-function telephone 18-m transmits the special number information corresponding to the special number operation to the control unit 12 (CPU 12a). ) To request an unresponsive status notification.

The control unit 12 refers to the information stored in the memory 12b, analyzes the received special number information, and recognizes that there is a request for a status notification that cannot respond.

The control unit 12 searches for the multi-function telephone 18-1 connected to the paging device 26 and making a call, and adds the multi-function telephone 18-1 to the multi-function telephone 18-1.
In order to notify that the other party using m is in an unanswerable state, the unanswerable notification tone generator 34 is connected to the extension trunk circuit 16-1 (multifunctional telephone 18-1) (4). . As a result, a non-response notification tone is transmitted to the multi-function telephone 18-1.

When a non-answering notification tone is transmitted to the multi-function telephone 18-1 and it is confirmed that the other party cannot respond, the multi-function telephone 18-1 causes the paging device 26 to perform a call operation. Is terminated.

The control unit 12 releases the paging device 26, disconnects the hold tone generating unit 36 connected to the local trunk 14-1, and releases the paging device 26.
1. The communication path between the office line via the extension trunk circuit 16-1 and the multi-function telephone 18-1 is connected, and the telephone is in a talking state. As a result, the operator of the multi-function telephone 18-1 can notify the caller from the central office that the call request partner cannot respond.

As described above, when the call partner called by the paging device 26 is in an unanswerable state,
By performing a predetermined operation (hooking + special number operation) on the multi-function telephone 18-m in use, the multi-function telephone 18-1 that has requested the call and the non-response notification tone generation unit 34 are connected. In addition, it is possible to notify that it is in a state in which a response is impossible by a response impossible notification tone.

(Embodiment 2) Next, the operation of the private telephone system in the second embodiment will be described with reference to FIG.

As shown in FIG.
Multifunctional telephones 18-1 to 18-1 connected to general extensions capable of responding to incoming calls from office lines via -1 to 14-n
In the group B accommodating the paging device 26 previously associated with 8-m, for example, the line trunk circuit 1
It is assumed that there is an incoming call via 4-1.

When the multi-function telephone 18-1 responds to the incoming call, the office line and the multi-function telephone 18-1 are transmitted via the office trunk circuit 14-1 and the extension trunk circuit 16-1.
The communication path with is connected to make a call (1).

Here, when the multi-function telephone 18-1 requests a hold for calling the other party requested by the caller, the control unit 12 sends the office trunk circuit 14-1 and the hold tone generation unit 36 And connect. Further, when the multi-function telephone 18-1 requests a call, the control unit 12 makes an outgoing connection between the multi-function telephone 18-1 and the paging device 26 via the extension trunk circuit 16-1 and the trunk circuit 24 (3). ).

Thus, the multi-function telephone 18-1 can call the other party by voice from the speaker 28 using the paging device 26.

At this time, the called party is using the multi-function telephone 18-m to talk to the other party of the multi-function telephone 18-2 (0), and cannot respond to the call from the paging device 26. , The called party performs the following special number operation on the multi-function telephone 18-m to notify the operator of the paging device 26 (the multi-function telephone 18-1) that the call cannot be answered. Can be notified.

First, when a hooking + special number operation is performed on the multi-function telephone 18-m by the called party, the multi-function telephone 18-m transmits the special number information corresponding to the special number operation to the control unit 12 (CPU 12a). ) To request an unresponsive status notification.

The control unit 12 refers to the information stored in the memory 12b, analyzes the received special number information, and recognizes that there is a request for an unresponsive status notification.

The control unit 12 searches for the multi-function telephone 18-1 which is connected to the paging device 26 and makes a call, and adds the multi-function telephone 18-1 to the multi-function telephone 18-1.
m to notify that the other party using m is in an unanswerable state.
0) to the extension trunk circuit 16-1 (multifunctional telephone 18-
Connect to 1) (4). Thereby, the multifunctional telephone 18
For -1, a voice message registered in advance in the talkie device 32 for notifying that it cannot respond is sent.

When a message is sent to the multi-function telephone 18-1 and it is confirmed that the other party cannot respond, the multi-function telephone 18-1 switches the paging device 26.
Is terminated.

The control unit 12 releases the paging device 26, disconnects the hold tone generation unit 36 connected to the local line trunk 14-1, and releases the paging device 26.
1. The communication path between the office line via the extension trunk circuit 16-1 and the multi-function telephone 18-1 is connected, and the telephone is in a talking state. As a result, the operator of the multi-function telephone 18-1 can notify the caller from the central office that the call request partner cannot respond.

Thus, when the other party called by the paging device 26 is in a state where it cannot be answered,
By performing a predetermined operation (hooking + special number operation) on the multi-function telephone 18-m in use, the multi-function telephone 18-1 that has requested the call is connected to the talkie device 32, and the voice message is transmitted. It can be notified that it is in an unresponsive state.

(Embodiment 3) Next, the operation of the private telephone system in the third embodiment will be described with reference to FIG.

As shown in FIG.
Multifunctional telephones 18-1 to 18-1 connected to general extensions capable of responding to incoming calls from office lines via -1 to 14-n
In the group B accommodating the paging device 26 previously associated with 8-m, for example, the line trunk circuit 1
It is assumed that there is an incoming call via 4-1.

When the multi-function telephone 18-1 responds to the incoming call, the line is connected to the multi-function telephone 18-1 via the office trunk circuit 14-1 and the extension trunk circuit 16-1.
The communication path with is connected to make a call (1).

Here, when the multi-function telephone 18-1 requests a hold to call the other party requested by the caller, the control unit 12 sends the hold signal to the line trunk circuit 14-1 and the hold tone generation unit 36. And connect. Further, when the multi-function telephone 18-1 requests a call, the control unit 12 makes an outgoing connection between the multi-function telephone 18-1 and the paging device 26 via the extension trunk circuit 16-1 and the trunk circuit 24 (3). ).

Thus, the multi-function telephone 18-1 can call the other party by voice from the speaker 28 using the paging device 26.

At this time, the called party is in a talk state with the other party of the multi-function telephone 18-2 using the multi-function telephone 18-m (0), and cannot respond to the call from the paging device 26. , The called party performs the following special number operation on the multi-function telephone 18-m to notify the operator of the paging device 26 (the multi-function telephone 18-1) that the call cannot be answered. Can be notified.

First, when a hooking + special number operation is performed on the multi-function telephone 18-m by the called party, the multi-function telephone 18-m transmits the special number information corresponding to the special number operation to the control unit 12 (CPU 12a). ) To request an unresponsive status notification.

The control unit 12 refers to the information stored in the memory 12b and analyzes the received special number information, thereby recognizing that there is a request for a status notification that cannot respond.

The control unit 12 searches for the multi-function telephone 18-1 which is connected to the paging device 26 and calls the multi-function telephone 18-1.
m, a message is sent to the multi-function telephone 18-1 to notify the multi-function telephone 18-1 that the other party is in a non-answerable state. Instruct 20-4 to display (4). As a result, a message notifying that the multifunctional telephone 18-1 is in an unresponsive state is displayed on the display unit 20-1.

When a message is displayed on the display unit 20-1 of the multi-function telephone 18-1 and it is confirmed that the other party cannot respond, the multi-function telephone 18-1 The call operation is terminated.

The control unit 12 releases the paging device 26, disconnects the hold tone generating unit 36 connected to the line trunk 14-1, and releases the line trunk circuit 14-.
1. The communication path between the office line via the extension trunk circuit 16-1 and the multi-function telephone 18-1 is connected, and the telephone is in a talking state. As a result, the operator of the multi-function telephone 18-1 can notify the caller from the central office that the call request partner cannot respond.

In this way, when the other party called by the paging device 26 is in an unresponsive state,
By performing a predetermined operation (hooking + special number operation) on the multi-function telephone 18-m in use, a message is sent from the control unit 12 to the multi-function telephone 18-1 that has requested the call, and the display unit 20 is displayed. Since it is displayed at -1, it is possible to notify that it is in an unresponsive state.

In the description of the first to third embodiments described above, the call partner called by the paging device 26 uses the multi-function telephone 18-m to enter a talk state with the partner of the multi-function telephone 18-2. Although it is assumed that there is a situation where it is not possible to answer for reasons other than talking on the multi-function phone, for example, being in a customer service or in a meeting, the person who was called or called When another person on the side of the user performs a special number operation on a telephone connected to a nearby extension, the operator of the paging device 26 (many times) confirms that the called party cannot respond. The function telephone 18-1) can be notified in the same manner as described in the first to third embodiments.

(Embodiment 4) Next, the operation of the private telephone system in the fourth embodiment will be described with reference to FIG.

In the second embodiment, the call partner called by the paging device 26 is
When a predetermined special number operation is performed for -m, the talkie device 32 and the calling multi-function telephone 18-1 are connected and notified by voice message that they cannot respond. On the other hand, in the fourth embodiment, when the operator who called from the paging device 26 operates the multifunction telephone 18-1 in a simple manner,
In other words, the case where a call operation using the paging device 26 is performed and then on-hook is performed is targeted.

In this case, a special number operation for notifying that the called party or another person on the called party side cannot respond to the call by the paging device 26 is connected to a nearby extension. When the call is made to the set telephone, the control unit 12
By analyzing the received special number information with reference to the information stored in, it is recognized that there is a request for a status notification that cannot respond.

The control unit 12 determines the office line on hold (the office line connected to the hold tone generating unit 36),
The talkie device 32 is connected to this office line instead of the hold tone generation unit 36 (4). This allows
A voice message for notifying that the telephone is in a state of being unable to respond, which is registered in advance in the talkie device 32, is transmitted to the station line where the call is received.

In this way, when the other party called by the paging device 26 is in an unresponsive state,
By performing a predetermined special number operation on the telephone, the talkie device 32 is directly connected to the held office line and a message is transmitted.
There is no need to tell from 1 that the other party cannot answer.

The present invention is not limited to the above embodiment, and various modifications and applications are possible.

[0075]

As described above, when the other party called from the paging device is already in a call with another telephone or cannot respond to the call, the extension which is already in a call or a nearby extension is called. From the extension phone in
By performing the hooking + dial operation or the dial operation, it is possible to connect a special sound or a talk key to the operator of the paging device and to notify that the called party cannot respond. Thereby, the operator of the paging device releases the paging device and makes it unnecessary for the extension / external line caller who is on hold and kept waiting that the requested party cannot answer the telephone. It is possible to notify without waiting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a private telephone system according to an embodiment.

FIG. 2 is a diagram for explaining the operation of the private telephone system in the first embodiment.

FIG. 3 is a diagram illustrating an operation of a private telephone system according to a second embodiment.

FIG. 4 is a diagram illustrating an operation of a private telephone system according to a third embodiment.

FIG. 5 is a diagram illustrating the operation of a private telephone system according to a fourth embodiment.

[Explanation of symbols]

 Reference Signs List 10 private branch exchange 12 control unit 12a CPU 12b memory 13 communication network 14-1 to 14-n office trunk circuit 16 extension trunk circuit 18-1 to 18-m multifunctional telephone 20-1 to 20-m display unit 26 Paging device 28 Speaker 32 Talkie device 34 Non-response notification tone generator 36 Hold tone generator

Claims (7)

[Claims] A terminal which accommodates an extension group constituted by terminals connected to a plurality of extensions and a paging device which is associated with the extension group in advance and is in a state of talking with an extension or an outside line. In the private branch exchange which is configured to hold a call partner by performing a special number operation and make an outgoing connection to the paging device, and to call a party requested to connect from the held call partner by the paging device, An input means for inputting a request for a status notification that cannot respond by a predetermined special number operation to a terminal of the extension group after a call is made by the paging device; and a request for a status notification that cannot respond is input by the input means. The paging device cannot respond to the called terminal. Private branch exchange, characterized by comprising a notification means for notifying that. 2. The private branch exchange according to claim 1, wherein the terminal that inputs a request for a status notification that cannot be answered by the input means is in a state of talking with an extension or an outside line. 3. The private branch exchange according to claim 1, wherein the terminal for inputting a request for a status notification that cannot be answered by said input means is a free extension terminal. 4. The non-response notification tone generating means for generating a predetermined tone signal indicating that the mobile telephone is in a non-response state, wherein the non-response notification tone generating means and the paging device are provided. 2. The private branch exchange according to claim 1, wherein the private branch exchange is notified that the terminal is unable to respond by connecting to the calling terminal. 5. The notifying means includes a voice generating means for generating a predetermined message indicating that it is in an unresponsive state, and a call is made between the unresponsive-notification tone generating means and the paging device. 2. The private branch exchange according to claim 1, wherein the terminal is connected to the terminal to notify that the terminal cannot respond by a voice message. 6. The terminal is provided with display means, and the notifying means sends a message indicating that it is in an unresponsive state to the terminal that called the paging device, and sends the message to the terminal. The private branch exchange according to claim 1, further comprising control means for displaying the information on the display means provided. 7. An incoming call is responded to by a vacant first telephone of a plurality of extension telephones, and the incoming call is set to a hold state in response to a predetermined operation on said first telephone. Calling the called party on the paging device, responding to the call on the paging device, responding to a predetermined operation on the second extension telephone, and notifying the first party that the incoming call cannot be answered. A telephone exchange method comprising: notifying a telephone set; and responding to the notification to a predetermined notification to a caller.