JP3251130B2 - Simple mobile phone system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simplified portable telephone system, and more particularly to a simplified portable telephone (PHP: Personal Handy Phone) system which can be used even in a private (extension) mode .
And private branch exchanges . In addition, this system
Is also called PHS (Personal Handyphone System)
However, in the following description, it is referred to as PHP.

[0002] The simplified portable telephone has a radio interface standard which is a radio interface standardization organization of Japan Radio System Development Center (RCR).
arch & Development Center for Radio Systems) enacted the “2nd generation cordless telephone system standard” (R
CR STD-28).

The RCR STD-28 is designed so that a simple portable telephone terminal (PS: Personal Station) can be used not only as a public network terminal but also as a digital cordless telephone terminal used in an office or at home. Therefore, the owner of the simplified portable telephone terminal can use the same telephone terminal in various places such as downtown, work, and home. In addition, call charges for simple mobile phones in public networks are expected to be significantly lower than current mobile phones, and widespread demand is expected for phones that are carried and carried by individuals at all times.

[0004]

2. Description of the Related Art The RCR STD-28 standard has a classification of public network / private network, and there are differences between the two. For example, the frequency of a control carrier for waiting for an incoming call or negotiating a communication channel to be used is different, the number of usable communication carriers is different, and layer 3 related to radio management, mobility management, and call control. Is a standard for public networks, but is a non-enforceable reference for private networks.

[0005] For this reason, when designing a simple portable telephone terminal that can be used in both the public network and the private network, there is a technical problem that it is necessary to support both the standards for the public network and the private network. is there. In addition, since there are operational problems such as a numbering system and charging, it is necessary for the user to be aware of whether to use the terminal as a public network terminal or a private network terminal.

FIG. 7 schematically shows the configuration of a conventional simplified portable telephone system. The simplified portable telephone terminal PS has two modes, a public mode and a self-service mode (however, the hardware is common). When switched to the public mode, the public network base station B is connected to the public network wireless interface.
It is connected to the public PHP network NW1 via S (Base Station), and when it is set to be switched to the private network mode, the private network base station CS (Cell Station) and private network PBX (private branch exchange) are connected via the private network wireless interface. Through the public fixed network N
The state of connection with W2 is shown.

Switching between the public mode and the private mode is performed by the user's operation. Even when making a telephone call, the user grasps the public network number system and the private network number system and uses them properly.

[0008]

FIG. 8 showing the case where the above-mentioned problem of the conventional configuration is applied to a department store will be specifically described below by way of example.

[Problem 1] In the OO department store DS shown in the figure, a base station CS for a private network is installed in the hall so that employees carrying the telephone terminal PS can communicate with each other no matter where they move in the hall. I have.

[0010] The radio interface between the telephone terminal PS and the private network base station CS is for the private network, and the private network base station CS is connected to the PBX, so that there is no charge when talking with an extension of the PBX. . However, when the user moves out of the library, the radio wave from the private network base station CS does not reach, so the public PHP network NW1 is used.

In this case, since the radio interface between the telephone terminal PS and the public network base station BS is for the public network, the telephone terminal PS must be switched to the public mode.

[0012] Therefore, the telephone terminal PS needs to have both the "public mode" and the "self-employed mode", which increases the cost. In addition, the user must switch between the two modes as appropriate.

[Problem 2] By the above switching operation, the telephone terminal PS becomes a terminal of the public PHP network NW1 having a different number system. For example, when the telephone terminal B calls the telephone terminal B of the PBX extension, the number is "3000". From “4000” to “777-1234”, and similarly, the number when calling from the telephone terminal B is also “4000” to “0-05”.
0-7775678 ".

As described above, even when a call is made from the telephone terminal PS to the same party, the number to be dialed is different when the telephone terminal PS is in the public mode and in the self-employed mode. Will be different.

[Problem 3] If the user forgets to switch to the self-employed mode when returning to the library from outside, "40
Even if there is an incoming call at "00", the telephone terminal PS cannot detect the incoming call.

As described above, when the telephone terminal PS is in the self-employed mode, the telephone terminal PS cannot respond even if there is an incoming call at the number of the public PHP network NW1. Conversely, when the telephone terminal PS is in the public mode, the telephone terminal PS cannot respond even if there is an incoming call at the number of the private network.

[Problem 4] In the above, the employee uses the telephone terminal PS.
However, in the case of a department store, there is a need to use the telephone terminal PS brought by the customer in the hall. However, since the telephone terminal PS brought by the customer does not include a number for identifying the system, an extension number, information for ensuring security, and the like, it cannot be used simply by switching to the self-employed mode. However, it is not realistic to register the information at the entrance of the department store one by one.

As described above, since only the registered telephone terminal PS can be used in the private network, even if a customer brings the telephone terminal PS to a department store or the like, it cannot be used as a terminal for the private network. .

[Problem 5] Therefore, if a public network base station is installed in the hall so that a public mode telephone terminal PS can be used, both the private network base station and the public network base station are used. It is uneconomical to install, and the efficiency of wireless use is reduced.

As described above, in order to use the public mode telephone terminal PS on the premises, it is necessary to install a public network base station in addition to the private network base station, which is uneconomical.

Therefore, the present invention provides a simplified portable telephone terminal operating with a public network protocol, a public network base station, and a public PH.
In a simplified mobile phone system configured with a P network,
To provide a simplified mobile phone system that can automatically make and receive calls regardless of the usage status of the simplified mobile phone terminal ; and
Automatically regardless of the usage status of the mobile phone
It is an object of the present invention to provide a private branch exchange capable of receiving a call .

[0022]

The interface between the public network base station and the base station accommodating device of the public PHP network is an ISDN (Integrated Services Digital Network).
The specifications are slightly modified based on the subscriber interface of the above, taking into account the interface of the wireless section. This base station connection interface, commonly called the I 'interface, is based on TTC (Telecommunication Technology).
The interface is a well-known interface standardized by the logy committee, and will be referred to in the following description as the "I 'interface".

Therefore, the simplified portable telephone system according to the present invention achieves the above object, as shown in FIG.
A PBX 10 is provided between the public network base station 13 and the base station accommodating device 12 of the public PHP network NW1, and the PBX 10 determines whether or not the PBX 10 has registered the simplified portable telephone terminal PS as an extension terminal. The connection control is performed between the station 13 and the base station accommodating device 12 of the public PHP network through an I ′ interface which is a protocol for the public network.

Therefore, the PBX 10 is used when the connection destination based on the call control information from the base station 13 is not the simplified portable telephone terminal PS registered as an extension terminal, or the simplified portable telephone registered as an extension terminal. Terminal PS
However, if the PBX 10 is not connected to the base station 13 accommodated by the PBX 10 via radio (if the location is not registered), the call control information is transferred to the base station accommodation apparatus 12 as it is. , An extension connection to the portable telephone terminal PS is performed.

In this way, the public simplified portable telephone terminal PS, which is connected to the base station accommodated in the PBX 10 via radio, is connected to the extension terminal of the PBX 10 and the base station 1 for the public network.
3 is connected to the portable telephone terminal P via wireless communication.
Consideration is given so that both S can be connected.

Further, the PBX 10 includes a speech path switch 11 for exchanging digital data such as voice signals,
The following means can be newly provided as shown in FIG.

1. Trunk circuit acting as a subscriber side of the I 'interface. 2. A circuit that exists inside or outside the trunk circuit 1 and extracts a downlink control signal received by the trunk circuit 1 and notifies the software of the extracted downlink control signal, Circuit to superimpose. 3. A subscriber circuit that operates as the network side of the I 'interface. 4. A circuit that exists inside or outside the subscriber circuit 3 and superimposes information specified by software on a downlink control signal transmitted by the subscriber circuit 3 and an uplink control signal received by the subscriber circuit 3 is extracted. A circuit that notifies software. 5. A circuit that stores the above software.

Inside the PBX 10, the communication path switch 1
1, a trunk circuit 1 operating as a subscriber side of the I 'interface and a subscriber circuit 3 operating as a network side of the I' interface are connected. Be exchanged.

The control signal extraction / superimposition circuit 2 extracts the signal of the downlink control channel of the I ′ interface received by the trunk circuit 1 and notifies the software storage circuit 5 of the extracted signal, and the information designated by the software storage circuit 5 FIG. 1 is a circuit having a function of transmitting as an uplink control channel signal of the I ′ interface transmitted by the trunk circuit 1.
Although the configuration example is inside the trunk circuit 1, it may be installed outside the trunk circuit 1 and connected via the communication path switch 11.

The control signal extracting / superimposing circuit 4 has a function of transmitting the information designated by the software storage circuit 5 as a signal of the downlink control channel of the I ′ interface transmitted by the subscriber circuit 3, and a function of receiving the information received by the subscriber circuit 3. A circuit having a function of extracting a signal of an uplink control channel of the I ′ interface and notifying the signal to the software storage circuit 5 is provided inside the subscriber circuit 3 in the example of FIG. Alternatively, they may be connected via the communication path switch 11.

The software storage circuit 5 exchanges information with the control signal extraction / superimposition circuits 2 and 4 to monitor signals on the control channel of the I ′ interface,
A function of issuing an instruction to transmit the information determined to be necessary as a signal of the control channel of the I ′ interface, and controlling the speech path switch 11 to perform a process of exchanging the signal of the speech channel of the I ′ interface. And controls all functions of the PBX 10.

On the other hand, outside the PBX 10, the public PHP network base station accommodation device 12 is connected to the I 'interface provided by the trunk circuit 1, and the public network base station 13 is connected to the I' interface provided by the subscriber circuit 3. .

The above-mentioned software storage circuit 5
It has a function of controlling connection of the communication channels of the trunk circuit 1 and the subscriber circuit 3, and can control extension connection of the portable telephone terminal PS to the public network base station 13.

Further, the control signal of the I ′ interface includes a control signal for position registration indicating that the base station 13 accommodated in the PBX 10 is connected to the base station 13 by radio, and the simplified portable telephone terminal. It can include call control information for outgoing calls from the PS and call control information for incoming calls to the simplified portable telephone terminal PS.

Further, the software storage circuit 5 of the PBX 10 is provided with a radio line for the number of the simplified portable telephone terminal PS registered as an extension terminal in the public PHP network NW1 and the base station 13 accommodated in the PBX 10. And information for identifying whether or not the connection is established via the terminal. If the number of the connection destination is not a public PHP network number registered as an extension terminal or an extension terminal If it is a public PHP network number registered as, but is not connected to the base station 13 accommodated by the PBX 10 via a wireless line, an instruction to send an uplink control signal having the same content as that notified is issued. If the downlink control signal is for controlling connection to a specific terminal of the public PHP network, a downlink control signal having the same content as the notified content is transmitted. It can be.

Further, when the downlink control signal is for controlling information to be reported to an unspecified terminal of the public PHP network, the software storage circuit 5 adds the independently generated information to the notified information. Can be transmitted.

[0037]

FIG. 2 is a block diagram showing an embodiment of a simplified portable telephone system according to the present invention. In FIG. 2, a PBX 10 includes a trunk circuit 1 and a subscriber circuit 3 located on both sides of a communication path switch 11. It has the same internal configuration as FIG. 1 except that two systems are installed. Also in this embodiment, it is assumed that the PBX 10 and the public network base station 13 are installed in a department store as a private network, as described above.

Two public network base stations 13 are connected to the end of the PBX 10, one of which is a paging area CA #.
One and another are for the paging area CA # 2. A and B are mobile phone terminals (PS),
It is assumed that A is a telephone terminal registered as an extension of the PBX 10 (for example, owned by an employee), and B is a general telephone terminal not registered in the PBX 10 (for example, owned by a customer).

The software storage circuit 5 of the PBX 10 stores a position management table PT as shown in the figure, and the telephone terminal PS registered as an extension of the PBX 10
Of the public PHP network NW1 is managed. For example, the telephone terminal PS (A) whose extension number (unique) is "4000" is moving out of the area (outside the building), or the telephone terminal PS (C) whose extension number is "4001" is a paging call. The fact that the user is in area CA # 1 can be determined by searching this table.

The PBX 10 is connected and controlled to the simplified portable telephone terminal PS by an I ′ interface, which is a connection interface between the public network base station 13 and the public PHP network base station accommodating device 12. The signals transmitted and received above are mainly classified into signal for position registration, call control information transmitted from the telephone terminal PS, and call control information transmitted to the telephone terminal PS.

Since the I 'interface is based on the ISDN subscriber interface, the call control signal is equivalent to the ISDN subscriber interface.
Since the location registration is a process unique to a simplified cellular phone / digital cordless phone, a brief description will be given before describing the embodiment.

First, location registration means that the location of the telephone terminal PS is located in the network so that an incoming signal is transmitted only from the base station near the telephone terminal PS when the telephone terminal PS is located. It refers to the process of registering in the database, and is specifically performed in the following procedure.

The base station 13 is divided into a plurality of groups, and a number called a paging area number is assigned to each group.
This group is a unit for sending an incoming signal.

Each base station 13 periodically notifies the assigned paging area number to each telephone terminal PS, and
S stores the received paging area number.

When the telephone terminal PS moves to the service area of another base station 13, the telephone terminal PS compares the general paging area number reported from the destination base station 13 with the stored general paging area number, and determines whether the both are at the same time. If they match, do nothing,
If they are different, it is determined that the mobile station has moved between the paging areas, and a position registration request signal is transmitted to the destination base station 13.

Base station 13 that has received the location registration request signal
Forwards this signal to the database. This base station 1
The paging area to which 3 belongs is registered as the location of the telephone terminal PS.

This location registration request signal is a signal independent of the call control signal in the wireless section, but is converted into a form of outgoing call control information in which a special number is set to the called number on the I 'interface. Transferred.

Signal Processing Example for Location Registration The signal processing example for location registration as described above will be described below with reference to FIG. 3. First, a public network connected to the subscriber circuit 3 of the PBX 10 A general paging area number different from the public network base station directly connected to the public PHP network NW1 existing near the PBX 10 is set in the public base station 13 as in the related art.

Thus, when the telephone terminal PS moves from outside the department store to the department store, the telephone terminal PS always sends a position registration request.

The location registration request is converted into an outgoing call control signal in which a special number is added to the called number, that is, a call setup message CM1 as shown in the sequence of FIG. The subscriber circuit 3 is notified.

The call setting message CM1 contains the public PHP network number of the telephone terminal PS that has sent the location registration request as a calling number. For example, the telephone terminal PS of FIG.
When (A) moves to the paging area CA # 2, the public PHP network number “050-7775” of the telephone terminal PS (A) is used.
Since “678” is included in the uplink control signal to the subscriber circuit 3, the software storage circuit 5 first determines whether or not the telephone terminal PS is registered as an extension in the location management table PT.
The public PHP network number is searched and checked (steps S1 and S2).

In this case, since "050-7775678" is present in the location management table PT, the software storage circuit 5 executes, as the next step, the paging area of the base station 13 for the public network which has transmitted the call setting message CM1. The number (that is, the paging area CA # 2) is written in the position information column of the position management table PT as shown in Table 1 below (step S3).

[0053]

[Table 1] When the rewriting is completed, a call setting message CM2 having the same content as the received call setting message CM is transmitted from the trunk circuit 1 to the public PHP network NW1 via the public PHP network base station accommodation device 12.

On the other hand, when the telephone terminal PS (B) shown in FIG. 2 moves to the paging area CA # 2, the public PHP network number of the telephone terminal PS (B) is stored in the location management table PT.
Therefore, it is determined that the mobile terminal is a general portable telephone terminal PS which is not registered as an extension, does not perform any processing, and transmits a call setting message CM2 having the same contents as the received call setting message CM to the trunk circuit 1. Sent from.

If the telephone terminal PS (A) moves further out of the general call area CA # 2 (outside the building), the location registration request signal goes up to the public PHP network, but this is reported to the PBX 10 at present. PBX10
Cannot update the position management table PT.

Therefore, when an incoming call arrives at the telephone terminal PS (A), the software storage circuit 5 of the PBX 10 calls the general call area CA # 2.
Since (A) is not in the paging area CA # 2, no response is returned.

However, the fact that this response is not returned serves as a means for knowing that the telephone terminal PS (A) has moved out of the area, and the position management table PT is updated at this time.

[0058] the processing example Figure 4 when calling from a telephone terminal PS illustrates the sequence example when dialing from a telephone terminal PS. Software storage circuit 5 of PBX 10
First, it is necessary to identify whether the called number included in the call setting message CM3 coming from the telephone terminal PS is a public PHP network NW1 (or public fixed network NW2) number or an extension number (step S11).

From the extension terminal of the PBX 10 to the public fixed network NW
In general, when calling to the public fixed network NW2, "0" is used as a calling special number to the public fixed network NW2.
Considering that when moving out of the building, it becomes a terminal directly connected to the public PHP network NW1, there is no special number when making a call to the public PHP network (or public fixed network), and a special number is provided when making an extension call It is more convenient.

If the identification result is an extension number, the software storage circuit 5 of the PBX 10 performs an extension incoming call process (step S14). If the identification result is a public PHP network number, as a next step, the public PHP network number in the location management table PT is used. (Step S12), and if there is a matching number, the extension incoming call processing (step S13 → S14) is performed because the telephone terminal PS is registered as an extension. If there is no matching number, a general terminal is used. Therefore, the call setting message CM4 having the same content as the received call setting message CM3 is transmitted from the trunk circuit 1.

[0061] the processing example Figure 5 during extension incoming call to the telephone terminal PS illustrates the incoming sequence example of the telephone terminal PS which is registered in the extension (step S14 in FIG. 4). First, the software storage circuit 5 of the PBX 10 checks the position information column of the corresponding telephone terminal PS in the position management table PT (step S141). If the telephone terminal PS is out of the area, the telephone terminal PS has moved out of the building, so the public PHP Network N
To call the telephone terminal PS via W1 (step S
142 → S147), the call setting message CM6 is transmitted from the trunk circuit 1.

If the paging area number where the telephone terminal PS is located is written, a call setting message CM5 is transmitted to all base stations belonging to the corresponding paging area (steps S142 → S143).

When the call setting acceptance message CR2 is received within a predetermined time (the telephone terminal PS responds), the incoming call processing is continued (steps S144 → S145).
However, if the telephone terminal PS does not respond within a certain time,
The telephone terminal PS judges that it has moved out of the hall, writes the out-of-area into the position information column of the position management table PT, and sends out the call setting message CM from the trunk circuit 1 (steps S144 → S146 → S147).

Incoming call from public PHP network to telephone terminal PS
Processing example in Figure 6 is an illustration of the incoming sequence example of the telephone terminal PS through the base station receiving device 12 from the public PHP network NW1. In this case, the PBX 10 may relay the message CM7 received from the trunk circuit 1 to the subscriber circuit 3 and the message CR3 received from the subscriber circuit 3 to the trunk circuit 1.

[0065]

As described above, according to the simplified portable telephone system of the present invention, the base station for the public network and the public P
A PBX is provided between the base station accommodating device of the HP network and the PBX.
X is configured to perform connection control at the base station connection interface for the public network between the base station and the base station accommodating device depending on whether or not the simplified mobile phone terminal is registered as an extension terminal. Specific effects can be obtained.

(1) Using a wireless protocol for a public network,
The telephone terminal PS of the private network can communicate in the private network without passing through the public PHP network without requiring mode switching in the public mode. (2) The owner of the telephone terminal of the private network can make a telephone call without being conscious of whether the user is in the private network or the other party is in the private network.

(3) A general telephone terminal PS not registered in the private network can make a telephone call in the private network.

In this way, the convenience and operability of the telephone terminal PS are remarkably improved, and at the same time, the economical operation of the private network becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an apparatus configuration of a simplified mobile phone system according to the present invention.

FIG. 2 is a block diagram showing an apparatus configuration of an embodiment of the simplified mobile phone system according to the present invention.

FIG. 3 is a sequence diagram of location registration in the simplified mobile phone system according to the present invention.

FIG. 4 is a call sequence diagram from a simplified portable telephone terminal (PS) in the simplified portable telephone system according to the present invention.

FIG. 5 is a sequence diagram of an incoming call to a simplified portable telephone terminal (PS) in the simplified portable telephone system according to the present invention.

FIG. 6 is an incoming call sequence diagram from the public PHP network to the simplified portable telephone terminal (PS) in the simplified portable telephone system according to the present invention.

FIG. 7 is a block diagram schematically showing a conventional configuration example.

FIG. 8 is a block diagram showing a conventional configuration example when applied to a department store.

[Explanation of symbols]

 PS Simple mobile phone terminal 10 PBX 1 Trunk circuit 2, 4 Control signal extraction / superimposition circuit 3 Subscriber circuit 5 Software storage circuit PT Location management table NW1 Public PHP network NW2 Public fixed network 12 Public PHP network base station accommodation device 13 Public Network base station In the figures, the same symbols indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04Q ^7/ 00-7/38 H04B ⁷ /24-7/26 102

Claims (10)

(57) [Claims] 1. A simplified portable telephone system comprising a simplified portable telephone terminal operating according to a public network protocol, a public network base station, and a public PHS network, wherein the public network base station and the public PHS network are provided. A base station for a public network between the base station and the base station accommodating apparatus, depending on whether the PBX has registered the simplified type mobile phone terminal as an extension terminal or not. Means for controlling connection by a connection interface , wherein the transmission to the public network number of the portable telephone terminal is
If the call is made via a base station for
The number of the mobile phone whose location is registered in X
, An extension call is made to the simplified mobile phone terminal.
Personal handyphone system, characterized in that that. 2. A personal handyphone system according to claim 1, wherein the PBX, and the trunk circuit is connected to the public PH S network base station accommodating apparatus operates as a subscriber of the base station connection interface A circuit provided inside or outside the trunk circuit, for extracting a downlink control signal received by the trunk circuit, notifying the software, and superimposing information specified by the software on an uplink control signal transmitted by the trunk circuit; A subscriber circuit operating as a network side of the base station connection interface accommodating a private extension terminal connected to the public network base station, and the software provided inside or outside the subscriber circuit. Information is superimposed on a downlink control signal transmitted by the subscriber circuit, and the uplink control signal received by the subscriber circuit is extracted and passed to software. A circuit for, personal handyphone system, characterized in that it is composed of a circuit which stores the software. 3. The simplified portable telephone system according to claim 2, wherein said software storage circuit has a function of controlling connection of a communication channel of said subscriber circuit, a function of analyzing said notified uplink control signal, and a function of analyzing said downlink. A simplified cellular phone system having a function of generating control signal information and instructing transmission, and performing extension connection control of the simplified cellular phone terminal to the public network base station. 4. The simplified portable telephone system according to claim 2, wherein the control signal of the base station connection interface is connected to a base station accommodated in the PBX via a wireless line. Characterized in that it includes a control signal for location registration indicating the location, call control information for outgoing call from the simplified mobile phone terminal, and call control information for incoming call to the simplified mobile phone terminal. Phone system. 5. The personal handyphone system according to any one of claims 2 to 4, the PBX software memory circuit, in the public PH S network of the personal handyphone terminal registered as extension terminal The base station stores a number and information for identifying whether or not the base station accommodated by the PBX is connected via a wireless line, and further analyzes the uplink control signal to determine whether the number of the connection destination is an extension terminal. If not a public PH S network number registered or is a public PH S network number which is registered as an extension terminal as the P
If BX is the base station that accommodates not connected through a radio line to transmission instruction an uplink control signal of the same content as notified content, a specific terminal of said downlink control signal is a public PH S network A simplified mobile phone system characterized in that, when connection control is performed, a down control signal having the same content as that notified is transmitted. 6. The personal handyphone system according to claim 5, in which the PBX software storage circuit further said downlink control signal to control the information to be broadcast to an unspecified terminal public PH S network A simplified cellular phone system characterized in that when there is, a control signal is transmitted to add a uniquely generated information to the notified information. 7. A private branch exchange for connecting the public base station and of Public PHS network, when the telephone terminal performing location registration to a public PHS network through the base station for the public is registered as extension terminal , the position information of the telephone terminal when requesting the location registration of said conductive <br/> talk terminal
A management means for updating is provided in the area, and transmission of the telephone terminal to the public network number is performed through the public base station.
If this is done, the PSTN number is managed by the management means.
If it is the number of the telephone terminal in the area
A private branch exchange characterized by receiving an extension call to a telephone terminal . 8. The private branch exchange according to claim 7, wherein said managing means is provided when said telephone terminal does not respond to said extension incoming call.
A private branch exchange that updates the location information of the telephone terminal outside the area . 9. The private branch exchange according to claim 7, wherein said extension means receives said extension at said telephone terminal .
If the location information of the telephone terminal is out of the area, or
A private branch exchange characterized in that when a talk terminal does not respond to the extension incoming call, a calling process is performed to the public PHS network. 10. The private branch exchange according to claim 7, wherein
hand, When an extension arrives at the telephone terminal, the telephone terminal
If it is located in the area, perform incoming call processing to the corresponding area
A private branch exchange characterized by having a configuration as described above.