JPH06253059A - Private branch exchange system - Google Patents

Abstract

PURPOSE:To obtain an exchange system in which an optimal route can be accurately selected. CONSTITUTION:This system is equipped with at least extensions 13-1-13-m and 2-1-2-m, and trunk lines 12-1-12-n and 5-1-5-m, and a route selecting function which selects the optimal route to be used from among the routes to be used constituted of plural kinds of lines in a tariff system according to the condition of a communicating party, time zone to be used, required communicating time, and date element or the like, based on the condition at the time of selecting the optimal route when transmission from the extensions to the trunk lines is operated. Also, the system is equipped with a holding means 15 which holds the required communicating time information per one time based on a communication result corresponding to each extension, and a control means 14 which uses the required communicating time information of the transmitting extensions obtained from the holding means 15 as one condition in order to select the optimal route based on those conditions, and operate transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a private branch exchange system capable of selecting an optimum route (utilization route) when transmitting from an extension terminal to an outside line (station line). .

[0002]

2. Description of the Related Art (First Prior Art) In recent years, a switching system has been using a microprocessor as a control center, and has become more intelligent and more sophisticated. By the way, a digital electronic exchange for a private branch exchange (hereinafter simply referred to as a private branch exchange) using a microcomputer accommodates an extension line and an outside line, and
In addition to the basic function of performing an exchange connection between an extension line and an outside line,
It enables various services.

One of these is a call type connection restriction called ground restriction. This is a connection regulation for out-of-city calling areas. For free extension connections, it is legal to connect to trunks connected to pay public networks, private networks, digital networks, packet switching networks, etc. Due to various restrictions from the above or on individual systems, and from administrative problems such as preventing unauthorized use of billed services such as long distance calls and international calls from extension lines,
Generally, the connection between the calling terminal and the outgoing trunk is based on the attributes of the calling terminal and its connection restriction class, the attributes of the outgoing trunk and its connection restriction class, and the dial information in order to require usage restrictions. The connection is controlled by determining whether or not.

In addition to ground control, service settings such as call forwarding, call forwarding, and call rejection can be set for each extension, and various service functions can be used within the set range.

[0005] Generally, call types of ground control and usable range of services are classified according to classes, and the classes are registered in each extension. In the exchange, each extension is permitted based on the registered class of the extension. Control this so that it can be used for a range of services.

On the other hand, in recent years, even if one public network is taken, in addition to the conventional NTT (Nippon Telegraph and Telephone Corporation) line, NCC (Shinden) specialized line service for long distance service is provided. There are multiple companies that do this, and there are also multiple service companies that also provide lines for international calls. And these serve the users with different fee systems.

By the way, in a private branch exchange capable of receiving the line service of each of these companies, in order to reduce the cost of communication, the extension call class of the extension used, the other party of the call, the call Some have a function of selecting a route in order to use an optimal line according to conditions such as a time zone and day of the week.

When the call originates from the extension, the station line trunk connected to the line that meets the above conditions is seized,
This is a function called optimum route selection in which a route is selected and transmitted by appropriately converting the dial number from the extension and outputting it to the network side.

Explaining with reference to FIG. 7, for example, a private branch exchange PBX accommodates lines of various networks NET1 and NETn such as a public network, a digital network, and a packet switching network as external lines, and may be a data terminal. For example, a digital network, a packet switching network, or a public network can be used. If a telephone terminal makes a call to a certain network (for example, the public network NET1 provided by NTT) from the extension terminal TEL1 of the private branch exchange PBX, It is possible to use the NTT public network as it is to reach the intended subscriber, or when the intended subscriber is a partner in the long-distance communication area, the NCC having a connection point at a nearby point in the public network NET1. Connection (NCCA, NCCB, or NCCN) is used to connect the long-distance section with this NCC line and connect near the other party. Public network of more again NTT NET1
In other words, it is possible to use the method of connecting to the target partner terminal TEL2.

The selection is performed by using the optimum route selection function of the private branch exchange PBX. To use this function, the extension terminal dials the special number for activating this function, and then the other party's telephone. Dial the number. Then, in the private branch exchange PBX, if the extension terminal is a telephone, the station line trunk connected to the public network is seized in order to select the public network, and today's day of the week or current time is determined by the dial number from the extension terminal. By selecting a trunk route that is a preset route to be used in consideration of the band, the location of the called party, etc., converting the dial information appropriately so that the route can be used, and outputting it to the network side. Select a route and make a call.

Here, "optimum" in the word "optimum route selection" means "lowest price",
Therefore, optimal route selection is often also referred to as cheapest route selection (LCR).

This function is carried out by preparing a "route selection table" for selecting the cheapest route in the storage unit as shown in FIG. This "route selection table" is a table in which the cheapest route can be read in order by giving information on the day of the week and time as selection conditions.

That is, as shown in the figure, the "route selection table" is provided for each ground, and the trunk route to be used is set corresponding to the day of the week and the time zone. Also, permission classes are set for each. Once the trunk route is decided, the route to be connected is decided by it. For example, the public network only or the line NCCA is used.

Here, the permission class is used to disable the use of routes of a certain level or higher depending on the extension class. In the cheapest route selection process, for example, the extension class value and the data table are used. The values of the permission class in the inside are compared, and if the value of the permission class of the extension is large (or if the value is small depending on how the value is set), the route is permitted to be used.

As described above, in the cheapest route selection function, the data to be referred when determining the station line trunk to be captured and the route to be selected are "extension class of the extension", "destination of call" and "call destination". It is known at the time when the local line is captured and the route is selected, such as "the time when the call is performed" and "the call quality required for the call".

On the other hand, the call charge determined by each type 1 telecommunications carrier or type 2 telecommunications carrier who provides the line is not limited to the time and day of the week when the call is made with the other party of the call. It also depends on the time (call duration). However, in the past, when selecting the cheapest office line trunk, it was not configured to add an element that is directly related to the charge called call time, so depending on the length of the call time actually used. , Which means that the cheapest route is not necessarily selected.

(Second Prior Art) On the other hand, in addition to the system having one private branch exchange, a plurality of extension lines and a plurality of office lines can be accommodated, and a central control unit and a storage unit for performing call control. As shown in FIG. 14, there is an exchange system in which a plurality of private branch exchanges equipped with are connected via a high-speed communication path. In the case of such an exchange system, when the local exchange accommodating the local exchange is blocked. If there is an empty office line of another exchange, it can be configured to be used.

That is, in the configuration example shown in FIG. 14, a plurality of outer lines LA11 to LAnn and a plurality of extension lines LB11 to LB11 are used.
Private branch exchanges PBXa to PBXn accommodating LBnns are connected by a high-speed communication path LC via stations ST1 to STn respectively provided.

Then, one of these private branch exchanges P
When a private branch exchange PBXm makes a call to an external line from the private extension terminal of the BXm and all the external lines of the type to be used are blocked, the private branch exchange PBm
Xm searches through its connecting station STm for a private branch exchange having an empty outside line of the same type as the above type, and calls through the station and the high-speed communication path LC to use the outside line of the private branch exchange with the empty outside line. Secure the extension communication path. Then, the outgoing extension is connected to the external line of the secured private branch exchange so that the called party can receive the incoming call.

As described above, in the above system, there are a plurality of private branch exchanges (hereinafter, each exchange is referred to as an exchange node) PB.
Of Xa to PBXn, when the extension of a certain switching node makes a call to an outside line (station line) of a certain type, when all the accommodating station lines of that type in the exchange node are blocked and there is no vacancy, another A group of office lines of the same type of exchange node is selected and transmitted.

The same type here means, for example, a digital line when the object is a digital line, a public network when the public network is used, and a packet switched network when the packet switched network is a line that conforms to the line quality and specifications. Refers to. Therefore,
For example, when an extension to be accommodated in a certain switching node wants to make a call to the public network, if there is no free station line in the public network in the own node, and if there is a free station line in the public network accommodated in another switching node, If you want to select and send it, or if the accommodation extension of a certain switching node wants to send to the digital network and there is no free station line of the digital network in your node, the station of the digital network accommodated in another switching node. If there is a free line, then that line is selected and transmitted, and the same type of network of other nodes is selected and used.

In this selection method, since there is a precondition that the same type of network is used, if there is no vacant station line desired to be used in the own node, immediately use of the same type of station line in other nodes will occur. As the number of communications across nodes increases, the blocking rate on the communication path between the switching node and the high-speed communication path increases. It may be difficult to take.

[0023]

[Problems to be Solved by the Invention] (Problems of the first prior art)

In a private branch exchange having a function called the least expensive route selection (LCR), the most economical route is selected and the line is connected when transmitting from an extension line to an outside line. When the private branch exchange determines the office line trunk to be captured and the route to be selected at that time, the data to be referred to are "extension class", "call destination", "time of call", and Is the "call quality required for a call", etc., and is only a known factor at the time of capturing a local line and selecting a route.

On the other hand, however, the call charge is not limited to the time and day of the week when the call is made with the callee, and varies depending on the length of the call depending on the line used.

However, in the prior art, when selecting the cheapest office line trunk, there was not a structure in which a factor directly related to the charge called a call time was taken into consideration, so that the call time actually used Depending on the length, there was a problem that the cheapest line trunk was not necessarily captured and selected.

As described above, in the conventional private branch exchange, the element which is directly related to the cost of the charge such as the call time zone is ignored, the cheapest office line is captured, and the route is selected. Depending on the length of time, there was a problem that the cheapest station line and route were not always available.

This is because the length of the call time itself is an element that can be determined only at the stage when communication is completed, and is an element that cannot be predicted in advance. Therefore, the conventional cheapest route selection function has not been fully satisfied with the original function of reducing the communication cost.

(Problem of the Second Prior Art) Further, in the exchange system having a constitution in which a plurality of private branch exchanges are connected through a high-speed communication path, which is the object of the above-mentioned second conventional art, a certain exchange accommodation If all the lines of a certain type are blocked, and if there is an empty line of the same type in another exchange, the use of the local node When all the desired station line groups are blocked, the station line groups of other nodes of the same type will be selected and used, but this selection method has the advantage that the station lines can be flexibly exchanged between nodes. On the other hand, on the other hand, since the proportion of communication that spans nodes increases, the block rate on the communication path between the switching node and the high-speed communication path increases, and depending on the traffic volume and the accommodation conditions of telephone and office lines Phone pleasure will not take, including the story, there is a drawback that lead to a decrease in customer service.

Therefore, a first object of the present invention is to provide a private branch exchange system having a cheapest route selection function capable of sufficiently exerting a communication cost reduction effect in order to solve the first problem. To do.

A second object of the present invention is to solve the second problem by connecting a plurality of private branch exchanges via a communication path to a free station line of the type desired to be used in the own exchange. In an exchange system that allows the use of a corresponding type of vacant office line in other exchanges when there is no such situation, the number of calls to the exchange line increases and the traffic volume of the communication path connecting the exchanges increases. An object of the present invention is to provide a private branch exchange system capable of suppressing the situation in which it becomes difficult to make telephone calls including extension calls due to the above, and improving user services.

[0032]

In order to achieve the above object, the present invention is configured as follows. That is, firstly, at least an extension line and an office line are accommodated, and when making a call from the extension line to the station line, a charge according to conditions such as the called party, usage time zone, communication required time, and date factor In a private branch exchange system having a route selection function capable of selecting and transmitting an optimum use route based on a known condition at least at the time of selecting a route from among the routes usable by a plurality of types of lines adopting the system, For each private branch exchange, 1 for each extension is based on the communication history of that extension.
Holding means for holding the communication required time information for each time is provided, and the control means is provided with the communication required time information of the transmission extension obtained from the holding means when the optimum utilization route is selected. It is used as one of the conditions of (1), and a function for selecting and transmitting an optimum route based on these conditions is provided and configured.

Secondly, a plurality of private branch exchanges (switch nodes) each accommodating a plurality of extension lines and a plurality of office lines and equipped with a control means for carrying out call control are provided via a high-speed communication path. In the connected exchange system, when a call is made from an extension line to a central office line, when all local exchange accommodation central office lines of the type corresponding to the line type used for the call are blocked, another exchange of the same type as the concerned line type When there is a vacancy in the accommodating station line, we will make it available, and when making a call to the station line from the extension accommodated in one of the private branch exchanges,
Based on at least the originating destination, the originating time zone, and the originating date information (day elements, such as the day of the week or holiday weekdays), the group of station lines that can be originated using the cheapest route available at that time, and the available station line group. In order to obtain the information for converting the necessary dial information to be sent to the network in order to secure the cheap route according to the priority order, the cheapest route selection control means gives priority to the station line used for using the obtained cheapest route. If the station line is secured, the dial information of the above-mentioned outgoing extension is changed so that it becomes the dial information of the cheapest route to be sent from this station line to the network. And send it to the network, and if there is no station line to use for the cheapest route, secure it to use the station line of another exchange,
In the exchange system that uses the station line to send dial information required for using the cheapest route to connect the outgoing extension to the called side by the cheapest route, inside the exchange that accommodates the outgoing extension to the central line In the case where there is no free office line available for use of the cheapest route, control is performed to use the free office line in the own exchange provided for the use of the cheapest route, which is temporarily the second best priority according to the setting. When neither of them can be used, a control means having a cheapest route selection function for controlling the station line of another exchange to be used is provided in each exchange.

[0034]

In the case of the above-mentioned first configuration, when making a call from the extension line to the central line, the time zone (time) to be used with the other party of the call, the date element (holiday weekday), the communication required time, etc. are satisfied. It had a route selection function that could select and transmit the most suitable route (route) based on the above conditions known at least at the time of route selection, from the routes that can be used by multiple types of lines that have a tariff system. In the private branch exchange system, holding means is provided to hold the communication required time information for each extension corresponding to each extension based on the communication record of the extension, and when the extension sends to the central line. When selecting a route, the control means reads out the communication required time information corresponding to the transmission extension from the information held by the holding means, and obtains the communication required time information of the transmission extension obtained by the above-mentioned known condition. Utilized as a single, selected and transmits the optimum route on the basis of these conditions.

In the case of the above-mentioned first configuration, the communication time associated with the past usage record for each extension (average call time, or actual call time such as estimated call time obtained by statistically processing the past call time for each extension terminal) The most economical usage route, in which the standard call time for that extension that reflects the above) is maintained, and when paying an outside line (station line) from the extension that accommodates the private branch exchange, considering the fee system that differs depending on the usage route. In selecting the cheapest route to connect by selecting, the other party, the time zone, the day element of the day of use (that is, the element of the day of the week, the element of whether it is a weekday or the day treated as a holiday), communication Since the cheapest route that can be used is selected by taking into account time (call time) information, the cheapest route can be used for actual communication (call), so economical operation is possible. Can provide private branch exchange system becomes possible.

In the case of the above-mentioned second configuration, when there is no free office line available for use of the cheapest route in the exchange accommodating the extension for sending to the office line, the priority order of the second best is temporarily set according to the setting. Use the free office line in the local exchange for the use of the cheapest route, and use the line of another exchange when neither is available.

Therefore, when trying to use the cheapest route, in the exchange that accommodates the extension transmitted to the office line,
If there is no free station line available for the cheapest route connecting the extension to the other party trying to communicate, by setting,
For the time being, use the station line that can be used for the second-best route with the lowest cost, and use the line of another exchange because it can be controlled to use the line of the other exchange for the first time when there is no available line Therefore, it is possible to suppress an increase in traffic on the communication path due to the use of the communication path between the exchanges (nodes).

[0038]

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

(First Embodiment) In the first embodiment of the present invention, when a call is made from an extension line accommodated in a private branch exchange having a cheapest route selection function to an external line, the caller's calling class and call (Communication) The lowest-cost trunk line trunk in consideration of the selection reference factors such as the destination, the type of communication, and the time at which the call (communication) is made, as well as the expected call (communication) time required for the extension. Is selected and a route is selected so that it can be operated more appropriately in terms of communication cost.

In the first embodiment, the call (communication) required time (hereinafter referred to as "call time") is related to the call charge, and from the viewpoint that this depends on the line used, the call time In consideration of the above, the cheapest route selection is made, but it is said that the length of the call time itself is an element that can only be determined at the stage when communication is completed and is an element that cannot be predicted in advance. Since it is a peculiar element, it has not been possible to include the call time in the element of the cheapest route selection in the past.

In the present invention, the element of the call time is estimated and obtained from the actual call time of the extension so that the call time close to the actual time can be obtained in advance, and this is added to the selection of the cheapest route. As a result, the cheapest route selection function that can satisfy the original function of reducing the communication cost is realized. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of a private branch exchange according to the present invention. In FIG. 1, 1 is an exchange main body, 2-1 to 2-m are extension telephones, and 3 is a relay stand provided at a reception desk. 4-1 to 4-m are dedicated lines and private lines, 5
-1 to 5-m are local lines. The exchange main body 1 accommodates extension terminals, office lines, dedicated lines, etc., and performs exchange connection between extension lines, between extension lines and outside lines, etc., and includes a communication path switch 11 and trunk circuits 12-1 to 12-n. , Line circuits (subscriber circuits) 13-1 to 13-m, control unit (central control device CC)
14, a storage unit 15, an interface 16 for a relay stand, a digital interface circuit 17, and the like.

The call path switch 11 is used for switching connection between extension lines or from extension line to outside line (station line or private line) and from outside line to extension line, and the control unit 14 performs line exchange operation of the call line switch 11. It controls all kinds of control including the control of.

The storage unit 15 stores various control programs and various tables of the control unit 14 and data such as set function contents, and other various information generated in the exchange, such as a calling extension. The storage unit 15 stores various information such as number information and its call (communication) time, the number of calls (communication count), the number of outgoing calls to the outside line, the telephone number of the destination, the call (communication) time, the call charge, and the current state. In addition to storing and updating the program, a program for controlling to exchange data with the maintenance terminal 6 is held.

Further, this system is characterized in that it is provided with a function of selecting the cheapest route for connection to the ground (connection to a long-distance call area). In particular, in this function, a call time factor is added. Then, the route can be selected.

In order to realize this function, according to the present invention, the average value of the call (communication) time of each extension or the most frequently used call duration of the call durations of each recent call is set to the extension. The call time is held in the storage unit 15 and used.

The control section 14 of the present system is provided with the cheapest route selection processing function. This cheapest route selection processing function is used for "extension class of extension", "callee" and "caller". "The time when the call is made", "The day on which the call is made (Holiday and New Year holiday handling days are treated as Sunday. Therefore, the information on weekdays / holidays is not the day of the week.)", "Calls required for calls" In addition to the factors known at the time of capturing a local line and selecting a route, such as `` quality, '' the selection process of the cheapest route that can be used at that time in consideration of the above-mentioned call time by line and its selection Line capture and route control on the route.

Although the function of selecting the cheapest route is a function that has been used in the past, this system is a function that allows the call time to be added to the conventional function and selects a route with a low call cost.

Therefore, in the present invention, the "route selection table" referred to in order to select the cheapest route is "extension calling class", "call destination", "time of call", "call line". It is set so as to guide the optimum route by selecting the selected day of the week, the call quality required for the call, and the call duration, and the "call by extension" to store the call duration for each extension. Time information table "
Is prepared so that the "call time" information of the originating extension can be obtained as the selection condition.

These tables are stored in the storage unit 15 respectively.
It is prepared in. Then, by using the route selection table, the cheapest route can be selected in consideration of the caller's calling class, the other party, the type of communication, the time at which the call is made, as well as the expected call time. The processing function of enabling selection and capturing the cheapest office line trunk selected by this and selecting a route is provided as one of the control functions of the cheapest route selection.

The maintenance terminal 6 described above has a keyboard and a display, and can input and change data and programs to the exchange main body 1 and read out data and the like. The digital interface circuit 17 is an interface for connecting the exchange main body 1 and an external digital device, and the maintenance terminal 6 is connected to the control unit 14 via the digital interface circuit 17. The digital interface circuit 17 is an interface capable of high-speed transmission of data and the like, and the maintenance terminal 6 is connected to the control unit 14 of the exchange main body 1 via the digital interface circuit 17 and can communicate with the control unit 14. Is done.

Line circuits 13-1 to 13 of the exchange main body 1
-M is a connection interface provided for each extension, and serves as a connection interface between the communication path switch 11 and each extension terminal. The trunk circuits 12-1 to 12-n interface with the call path switch 11 and the corresponding office lines, leased lines or private lines 4-1 to 4-m, and are also used to detect incoming calls and capture lines. It is a circuit that closes the DC loop.

Under the control of the control unit 14, the speech path switch 11 is controlled by the line circuits 13-1 to 13-m and the trunk circuit 1.
The normal switching operation is enabled by controlling the communication path between 2-1 to 12-n. In addition to this, a tone signal generator 19 is connected to the speech path switch 11 so that various signal sounds necessary for the telephone system can be transmitted.

The interface 16 is used to connect the relay stand 3 and the exchange main body 1, is one of the terminal control cards, and has a function of exchanging voice, data, and control signals with the relay stand 3. ing.

Each terminal control card such as the line circuits 13-1 to 13-m, the trunk circuits 12-1 to 12-n, and the interface 16 and the control unit 14 exchange signals with the control highway 18. Since the card is assigned to the input / output port, each port has its own port number decoding means so that the terminal can be specified in the form of a port number to identify it. At that time, it is recognized as access to oneself.

The above-mentioned components in the exchange main body 1 are connected to the control unit 14 via the control highway 18, and the control unit 14 follows the line circuits 13-1 to 13-1 in accordance with the control program stored in the storage unit 15 in advance. 13-m and trunk circuits 12-1 to 12-n are controlled so that a communication path is formed between them to enable a normal exchange operation. In order to realize these controls, the storage unit 15 is provided with programs and data for performing various controls based on dial information, such as selecting a partner port number to be exchange-controlled and off-hook and on-hook signals. Has been done.

In this system having such a configuration, if there is an incoming call from an outside line, the control unit 14 causes the trunk circuits 12-1 to 12-1.
An extension terminal (in the case of a repeater system or extension group system) that is set as a representative by detecting an incoming call from 12-n, or
The call is directly sent to a corresponding extension (PBX dial-in; a method of receiving a subscriber number from NTT and assigning it to the extension to directly receive the call by dialing the subscriber number). Then, the communication path is secured by the response of the extension terminal, and the communication between the two is enabled. To transfer this call to another extension, use the transfer operation from the receiving terminal.

Then, the control unit 14 checks the restriction or the like for the transfer destination extension and then calls the extension if the connection is possible. When the other party responds, the extension terminal that has performed the transfer operation is turned off, so that the control unit 14 secures the communication path between the transfer destination extension and the calling side external line and enables the two parties to talk.

In response to a call from the extension to the reception desk, the control section 14 controls to make an incoming call to the relay stand 3 which is the receiving side terminal. When the relay stand 3 responds, the control section 14 makes a call. The call path between the calling side and the called side is secured and communication between them is enabled.

Between the extensions, receiving the extension number from the calling extension,
Check the connection regulation between the extensions, if the connection is possible, control the incoming call to the line circuit of the corresponding extension number, and secure the call path by the connection terminal of the line circuit responding,
Enable communication.

When the call from the extension line to the outside line does not depend on the cheapest route selection special number, the control unit 14 operates the call operation of the extension terminal to cause the control unit 14 to select an empty trunk circuit 12-1 to 12-n. After looking for a thing and checking the connection restriction with the calling extension, if there is a connection, the empty trunk circuit is used to secure the communication path and the dial information is output to the central office switch. Then, it becomes possible to communicate when connected to the other party via the central office.

Various controls including outgoing / incoming control of the trunk circuit and the line circuit are performed using the port number. For example, if a certain extension A is assigned to the port number PN n, the extension A is assigned. When calling, the method of accessing the port number PN n is used. Such control is realized by the control unit 14 controlling based on the terminal-port number information stored in the storage unit 15.

In the present system, when a call is made by dialing the lowest cost route special number in order to use the lowest cost route function, the line connection is made by the lowest cost route that can be used by the system at that time. Is characterized by the fact that it realizes a service function that enables the communication to be performed economically, and this control will be described in detail below.

FIG. 2 shows an "extension call time table" which is a table for storing the call time for each extension telephone set prepared in the storage unit 15 for realizing the cheapest route selection function according to the present invention. It is shown. In the "Call time table for each extension", the average call time is set for each extension number. If you know the extension number, you can read the stored data corresponding to it so that the call time information for the extension of that extension number can be obtained. Has become.

This "extension call time table" is set under the control of the control unit 14 by a setting command from the maintenance terminal 6, or the control unit is provided with a call time statistical program in the exchange 1. 14 is configured to be able to perform statistical processing, the call time statistics program is based on the records of calls for a certain period,
The control unit 14 is caused to calculate the average call duration, and the result is set in the storage unit 15.

Also, this "extension call time table"
The extension may be the average call time in the calls up to now, or the call time with the most number of times may be selected and used from the call frequencies according to call durations. It should be set in a logic that can make the most of.

FIG. 3 shows an example of the "route selection table" prepared in the storage unit 15 for selecting the cheapest route according to the present invention. "Route selection table"
As shown in the figure, it is provided for each ground (by area for long-distance calls), and the trunk route that should be used according to the day of the week, the time zone, and the call time (use with the trunk line used) Information indicating the line route (NTT line, NCC line) (information in the table describing the information of the trunk route) and the permission class are set, and the day of the week, the time zone, the call time and the permission class are given. Thus, the trunk routes that meet these conditions can be sequentially read as the cheapest route. Next, the operation of the present system having the above configuration will be described. FIG. 4 is a flow chart showing a process for making an outside line using the function of selecting the cheapest route.

Now, when a call is made to an extension terminal and an LCR (lowest cost route selection) transmission special number is dialed from the extension (S1), the control unit 14 which has detected this is first stored in the storage unit 15. The information of the extension calling class that exists is read (S2), and it is checked whether or not the call is permitted to the extension ((S3); call permission extension check). And, as a result, if the extension is restricted,
A restriction sound is generated (S4) to notify the extension operator that the extension cannot be transmitted.

On the other hand, if the extension is not regulated, then dial information from the extension is accumulated (S5),
It is checked whether or not the ground is restricted, that is, whether or not it is an extension line for which restriction for outgoing calls to outside lines is set ((S
6); Check the ground control class).

As a result, if the call to the ground is set to be permitted, the call time of the extension is obtained from the "call time table for each extension", and the obtained call time information and the ground call issued from the extension are obtained. Based on the information and today's day of the week and current time obtained from the clock calendar function of the control unit 14, the "route selection table" is used to read the trunk route with the lowest communication cost (S8). .

In the "route selection table", a trunk route table (LCR route table) that stores trunk routes that meet the selection conditions can be selected by the trunk route number, and the trunk route table (LCR route table) is selected. If this is the case, the station line to be used, the dial information content to be changed, etc. are preset in this table, the station line trunk of the station line set here is captured, and according to the dial information content to be changed, If you change the part of the dial information from the outgoing extension to be changed and send it to the trunk line trunk, you can secure the line with the selected cheapest route,
You will be able to talk to the other party on the cheapest route. Therefore, if the route obtained in step S8 is available (S
9), the control unit 14 captures the office line and then sends dial information (S10).

When the selected trunk route cannot be used because it is busy or the like, the control unit 14 reads out the trunk route with the next lowest communication cost (S11), and determines whether the route is vacant or blocked. Then, if the route is free (S9), the control unit 14 captures the office line and then transmits dial information (S10).

When the route cannot be used because it is busy, the control unit 14 checks whether or not there is a next route in order to read out the trunk route which has the next lowest communication cost (S11). Read it (S
12). Then, it is determined whether the route is vacant or blocked (S9), and if it is vacant, the control unit 14 captures a station line that can be used for the route and transmits dial information (S10). If the result of the check in step S9 is that there is no vacant route, the above-described operation is repeated in order to find the next best route and then the route with the cheapest cost.

In this way, the cheapest available route is searched for, the optimum office line to be used for that route is captured, and the necessary dial change processing is applied to the dial information from the outgoing extension. After that, the dial information is transmitted so that the communication can be performed using a route that increases the communication cost.

There are cases where the routes that can be used are limited depending on the extension class, but when none of the routes allowed for the outgoing extension is available, a busy tone is emitted, or the next service such as waiting for an availability is activated (S11). , S13).

FIG. 5 illustrates how the cheapest route selection according to the present invention is performed. In FIG. 4, reference numerals 2a to 2d denote terminals accommodated in the exchange 1 as extension terminals. Among these, 2a and 2b are analog telephones for business use, 2c is a facsimile terminal, and 2d is for performing data communication. Each shows an analog modem terminal.

Reference numeral 21 is a call time table for each extension.
The average call time information for each extension terminal is stored, and 20 indicates a route selection table for the ground X. The route selection table 20 for the ground X is composed of items such as a day of the week, a time zone, a call time, a trunk route, and a permission class. For example, on Monday, from time T1 to T2.
Up to, if the call duration is within 3 minutes and the permitted class is in the range of 7, the connected trunk line trunk of the office line (external line) listed in the trunk route table of number TGN1 is the optimum trunk route. Is selected, and if the permitted class is within the range of 15 under the same conditions, an external connecting station line trunk that can use a route defined in advance in the trunk route table of TGN2 is selected as the optimum trunk route. , Between T1 and T2 on Monday, if the talk time is within 10 minutes, and the permitted class is in the range of 7, T is the optimum trunk route.
An external connecting line trunk that can use the route specified in the GN1 trunk route table is selected, and if the permitted class is within the range of 15 under the same conditions, the optimum trunk route is specified in the TGN2 trunk route table. That is, an external connecting line trunk that can use the route is selected.

Then, assuming that each extension terminal shown in the figure makes a call to the ground X at time t (T1 ≤ t ≤ T2), the extension call time table 21 and the route selection table 20 are used to derive the call. The route selection order is 30a to 33c.

That is, in the case of the business telephone A of the permission class "7" indicated by reference numeral 2a, the extension call time table 2
Since the call duration held in 1 is 4 minutes, the first candidate, which is the best candidate, is selected from the corresponding item of the route selection table 20.
The trunk route table TGN1 is selected as the candidate 30a, and the outside line set in the trunk route table TGN1 is used. When the trunk line table TGN1 is unavailable, the permission class "7" is permitted as the second candidate 30b which is the next best candidate. If the trunk route table TGN2 of the class "15" is selected and the modem terminal 2d of the permitted class "7" is used, the call time held in the extension call time table 21 is 15 minutes. From the corresponding item of 20, the trunk route table TGN1 is selected as the first candidate 33a and the permission class "7" is allowed as the second candidate 33b. The trunk route table TG of the permission class "10" is permitted.
N4 is selected, and the trunk route table TGN2 of the permission class “11” in which the permission class “7” is permitted is selected as the third candidate 33c.
In this way, as a result of controlling to use in order from the highest rank among the candidates, the cheapest route available at the present time can be selected.

The type of office line to be used, the contents of dial information to be changed, etc. are preset in the trunk route table, and the office line trunk of the station line of the type set here should be captured and changed. By changing the part of the dial information from the outgoing extension to be changed according to the dial information content and sending it to the trunk line trunk, the line with the selected cheapest route can be secured, and the other party with the cheapest route can be secured. You will be able to call.

In the above embodiment, in essence, at least the extension line and the office line are accommodated, and when making a call from the extension line to the office line, the destination of the call, the time (time zone), and the daily factor (holiday weekday or day of the week; Holidays include the days martyred on a holiday),
Select and transmit the most suitable route (route) based on known conditions at least at the time of selecting the route from among the routes that can be used by multiple types of lines that have a fee system according to the conditions such as communication time In a private branch exchange system having a route selection function capable of performing the above, a corresponding holding means is provided for holding each communication required time information based on the communication history of the extension corresponding to each extension, and selecting the optimum use route. In this case, the communication required time information of the transmission extension obtained from the holding means is used as one of the known conditions, and the control means for selecting and transmitting the optimum route based on these conditions is provided. When the extension makes a call to the central office line, when selecting the route, the communication required time information corresponding to the originating extension is read from the information held by the holding means. By using the communication time information of the outgoing extension obtained by the above, together with the other party of the call, the time zone, and the factors of the day, it is used as a selection condition.By selecting the optimum route based on these conditions and making a call The communication required time information can be used as known information.

As described above, according to the embodiment of the first invention, the call time information (call duration information), which is one of the important factors in determining whether the call charge is high or low, is used as the extension. Based on the past record of usage time of each time, it is obtained and stored in a table provided for extension lines, and when making an outside line from the extension line, the time to call to the ground and the day of the week (public holidays, year-end and New Year holidays, etc.) The day when the holiday charge is handled is the same as Sunday), and the route selection order is determined by referring to this call time as well, so more detailed route settings can be made, which in turn greatly contributes to call cost reduction. To do.

In the above embodiment, what is stored in the memory as the call duration may be the average call duration or the call duration with the largest number of calls obtained from past call records. Furthermore, any other time can be set. Also, the setting in the call time table may be done by a data setting command,
It is also possible to place a statistical program of the call time in the exchange and automatically update the contents such as a table with the result of automatic measurement.

The above has described an example of selecting the cheapest route for the accommodation station line in one private branch exchange. Next, we will improve the extension service in the exchange system by connecting multiple private branch exchanges via a communication path so that when there is no free office line in the local exchange, it is possible to use the free office line in another exchange. An enabling example will be described as a second example.

(Second Embodiment) Here, a plurality of private branch exchanges are connected to each other via a communication path so that when there is no free office line in the own exchange, an empty exchange line in another exchange can be used. In such an exchange system, it is possible to suppress the situation where it becomes difficult to make calls including extension calls due to an increase in the number of calls to the central office line and an increase in the traffic volume of the communication path connecting the exchanges. An example of a private branch exchange system capable of improving user services will be described.

In this embodiment, the cheapest route selection (LC
In the "route selection table" used for R), the own node priority flag is provided for each detour route, and if the line groups are equivalent in call charge, call quality, etc., this flag is set to give priority to the own node. All of the station line groups (station line trunks required to use the route selected in the cheapest route selection) are blocked, and priority station line groups of other nodes (use the route selected in the cheapest route selection above) Even if there is a vacant station line in the station line trunk that is connected to the same type of station line trunk as the required station line trunk, the equivalent station line group in the local node is used, and the priority station of another node Do not circumvent the line group.

An example will be described. In FIG. 8, three switching nodes (private branch exchanges) are connected by an optical loop. 1
a to 1c are switching nodes (private branch exchanges), 82 is an optical loop that connects these switching nodes 1a to 1c and forms a communication path between the switching nodes, and 83a to 83c connect optical repeaters and switching nodes and optical loops. A station having an interface function to perform communication, an extension telephone 85a in which 84a to 84c are accommodated in each switching node 1a to 1c
~ 85c is the first priority station line group (station line group number:
1) and 86a to 86c are the second priority station line group (station line group number: 2) of the present system, and in this embodiment, the first priority station line group 85a to 85c and the second priority station line group 86a to 86.
Both c have the same functions in terms of call charges and call quality.

The first priority station line group refers to station line trunks required to use the route selected in the cheapest route selection,
The second priority station line group refers to a station line trunk connected to another type of network satisfying the transmission quality and the communication standard almost equal to those of the first priority station line group.

In the switching nodes 1a to 1c, when the cheapest route selection is used when making a call from the extension accommodated in itself to the external line, the trunk line in the switching node is required to use the selected route. If there is no free space, use the free space of another exchange node to bypass. In order to obtain this vacant information, this system uses stations and optical loops to transmit the current information of the self-accommodating line to each other to notify each other, and to provide the information for each type of the current line respectively. In the exchange node of
It is kept in a table so that it can be referred to when necessary.

When the accommodating station line in the other premises node is used as a bypass route, the own exchange node sends an instruction for setting the right of use of the station line of the type to be used to the other exchange node, By this, the exchange node of the other party sets the right to use the above-mentioned type of unused office line trunk and captures the line, and thereafter, via the station and the optical loop, the station line trunk that set the usage right and the requester A transmission path is established with the switching node to send dial information, and information can be transmitted between the requesting extension terminal and the above-mentioned office line trunk.

FIG. 9 is a block diagram showing the configuration of the private branch exchanges 1a to 1c. In the figure, 84-1 to 84-m are extension telephones, which correspond to 84a to 84c in FIG. Reference numeral 83 denotes a station, which is 83a in FIG.
~ 83c.

Further, 85-1 to 85-m are the first priority station line group (station line group number: 1) and correspond to 85a to 85c in FIG. 86a to 86c are second priority station line groups (station line group number: 2) and correspond to 86a to 86c in FIG.

The exchange main body 1a (to 1c) accommodates extension terminals, office lines, leased lines, etc., performs exchange connection between extension lines, between extension lines and outside lines, and a line accommodated in its own exchange in another exchange. The communication path switch 11, the trunk circuits 12-1 to 12-n, the line circuit (subscriber circuit) 13
-1 to 13-m, a control unit (central control device CC) 14, a storage unit 15, an interface 16 for interfacing with the station 83, a digital interface circuit 17, and the like.

The call path switch 11 is for performing switching connection between extension lines or from extension line to outside line (station line, etc.) and from outside line to extension line, and the control unit 14 controls the line switching operation of this communication line switch 11. In addition, it controls various controls of the whole.

The storage unit 15 stores various control programs of the control unit 14, various tables, and data such as set function contents, and other various information generated in the exchange, such as a calling extension. Various information such as number information and its call time, the number of calls, the number of outgoing calls to the outside line, the telephone number of the destination, the call time, the call charge, and the current state are updated and stored in the storage unit 15, and the maintenance terminal 6 A program and the like for controlling data exchange with the computer are held.

In the present system, as described with reference to FIG. 8, in the switching nodes 1a to 1c, when the cheapest route selection is used when making a call from the extension accommodated in itself to the outside line, the selected route is selected. When there is no vacancy in the internal trunk of the local exchange node necessary to use the, the circumstance is detoured by using the vacancy of another exchange node. In order to obtain this vacant information, this system uses stations and optical loops to transmit the current information of the self-accommodating line to each other to notify each other, and to provide the information for each type of the current line respectively. It is stored in a table in the exchange node of and can be referred to when necessary.

When the accommodating station line in the other premises node is used as a detour route, the own exchange node sends an instruction for setting the right of use of the station line of the type to be used to the other exchange node, By this, the exchange node of the other party sets the right to use the above-mentioned type of unused office line trunk and captures the line, and thereafter, via the station and the optical loop, the station line trunk that set the usage right and the requester A transmission path is established with the switching node to send dial information, and information can be transmitted between the requesting extension terminal and the above-mentioned office line trunk.

In addition to this system, the following system may be used. That is, in the switching nodes 1a to 1c, when the cheapest route selection is used at the time of making a call from the extension accommodated in itself to the outside line, the trunk line in the own switching node required to use the selected route is used. If there is no free space, ask the other switching node via the station and the optical loop whether there is a free trunk line trunk that accommodates a line of the same type as the type you want to use, and the free switching node will answer this inquiry. On the other hand, a reply with a vacancy is returned to the inquiry source, and the inquiry source that receives this sends an instruction for setting the trunk usage right to the response source, and the response source uses this to send an empty trunk of the above type at the inquiry source. Set the right to use and capture the line, then inquire through the station and the optical loop with the trunk line trunk to which the right to use is set. It was established a transmission path between a source switching node, performs the transmission of dialing information, enabling information transmission between the originating extension terminal and office line trunk set the usage rights. The control unit 14 also has a control function necessary for realizing such a function.

In addition, in the present system, when making a call from an extension line to an outside line, in addition to the function of selecting the cheapest route as described above and making a call using the selected route, the own node (self-switch) If there is a group of external lines (station lines) of the same level in terms of call charges and call quality, all the priority station lines of the local node are blocked and the priority stations of other nodes. Even if there is an empty station line in the line group, the equivalent station line group in the own node is used and the function is provided to control so as not to bypass to the priority station line group of another node. There are features.

In order to realize this function, the "route selection table" used for the cheapest route selection (LCR) is provided with its own node priority flag for each detour route, and the same line group is used in terms of call charges and call quality. If this is the case, by setting this flag, if all of the priority station line groups of the own node are blocked, use the equivalent station line group of the own node, and the equivalent station line of the own node. The control unit 14 has a function of making a detour to the above-mentioned priority station line group of another node only when all the groups are closed.

The above-mentioned maintenance terminal 6 has a keyboard and a display, and can input and change data and programs, read data and the like to the exchange main body 1. The digital interface circuit 17 is an interface for connecting the exchange main body 1 and an external digital device, and the maintenance terminal 6 is connected to the control unit 14 via the digital interface circuit 17. The digital interface circuit 17 is an interface capable of high-speed transmission of data and the like, and the maintenance terminal 6 is connected to the control unit 14 of the exchange main body 1a (to 1c) via the digital interface circuit 17, and the control unit I am able to communicate with 14.

Line circuit 1 of switch body 1a (to 1c)
3-1 to 13-m are connection interfaces provided for each extension, respectively, and serve as connection interfaces between the communication path switch 11 and each extension terminal. The trunk circuit 12-1
.. 12-n interface with the communication path switch 11 and the corresponding office lines 85-1 to 85-m and 86-1 to 86-m respectively, and a DC loop is closed to detect an incoming call and capture a line. It is a circuit for performing the above.

Under the control of the control unit 14, the speech path switch 11 is controlled by the line circuits 13-1 to 13-m and the trunk circuit 1
The normal switching operation is enabled by controlling the communication path between 2-1 to 12-n. In addition to this, a tone signal generator 19 is connected to the speech path switch 11 so that various signal sounds necessary for the telephone system can be transmitted.

The interface 16a is used to connect the station 83 and the exchange main body 1a (to 1c), and is one of the communication control cards.
3 has a function of exchanging voice, data, and control signals with the unit 3.

The station 83 exchanges data with the optical loop 82, which is a high-speed communication path, and takes in transmission data to the switching node to which it is connected, sends transmission data from the switching node to which it is connected, etc. It has the function of.

Signals are transferred between the terminal control cards such as the line circuits 13-1 to 13-m, the trunk circuits 12-1 to 12-n, and the interface 16 and the control unit 14 by the control highway 18. Since the card is assigned to the input / output port, each port has its own port number decoding means so that the terminal can be specified in the form of a port number to identify it. At that time, it is recognized as access to oneself.

The above-mentioned constituent elements in the exchange main body 1a (to 1c) are controlled by the control unit 14 via the control highway 18.
The control unit 14 is connected to the line circuits 13-1 to 13-in accordance with a control program previously stored in the storage unit 15.
m and the trunk circuits 12-1 to 12-n are controlled so that a communication path is formed to enable a normal exchange operation.
In order to realize these controls, the storage unit 15 is provided with programs and data for performing various controls based on dial information, such as selecting a partner port number to be exchange-controlled and off-hook and on-hook signals. Has been done.

In this system having such a configuration, if there is an incoming call from an outside line, the control unit 14 causes the trunk circuits 12-1 to 12-1.
An extension terminal (in the case of a repeater system or extension group system) that is set as a representative by detecting an incoming call from 12-n, or
The call is directly sent to a corresponding extension (PBX dial-in; a method of receiving a subscriber number from NTT and assigning it to the extension to directly receive the call by dialing the subscriber number). Then, the communication path is secured by the response of the extension terminal, and the communication between the two is enabled. To transfer this call to another extension, use the transfer operation from the receiving terminal.

Then, the control unit 14 checks the restriction or the like for the transfer destination extension and then calls the extension if the connection is possible. When the other party responds, the extension terminal that has performed the transfer operation is turned off, so that the control unit 14 secures the communication path between the transfer destination extension and the calling side external line and enables the two parties to talk.

Between extensions, the extension number is received from the calling extension,
Check the connection regulation between the extensions, if the connection is possible, control the incoming call to the line circuit of the corresponding extension number, and secure the call path by the connection terminal of the line circuit responding,
Enable communication.

When a call is made from an extension to an extension accommodating another switching node, the control unit 14 makes a call from the station 83 to the target switching node via the interface 16a so as to receive the call at the extension which is the receiving party. When the switching node sends the desired extension and the desired extension responds, the control unit 14 of each switching node secures the call path between the calling side and the called side, and the interface 16a, station 83, and It enables communication between the two via an optical loop. The same is true when the incoming call is transferred from the outside line to the extension inside the other switching node.

When the call from the extension line to the outside line does not depend on the lowest-priced route selection special number, the control unit 14 operates the call operation of the extension terminal so that the trunk circuit 12-1 to 12-n is not occupied. After looking for a thing and checking the connection restriction with the calling extension, if there is a connection, the empty trunk circuit is used to secure the communication path and the dial information is output to the central office switch. Then, it becomes possible to communicate when connected to the other party via the central office.

In the case where the extension call is made by dialing the lowest-price route special number to use the lowest-price route function and the external line accommodated in the own exchange node can be used, the first embodiment The operation is similar to that described in.

Next, in the self switching node, when the external line used by the route selected by the cheapest route function is not available, that is, when the office line trunk used by the selected route is not available. The operation will be described.

FIG. 10 shows an example of the "route selection table". The "route selection table" shown in the figure has a different display format from that of the first embodiment, but the contents are substantially the same, and of course the one of the first embodiment may be used as it is. As shown in the figure, this "route selection table" is provided for each ground (by area for long-distance calls), and the trunk route that should be used according to the day of the week, time zone, and call time (use Route table information (TGN1, TGN2, etc.) that stores information on office line trunks and line routes such as NTT lines and NCC lines used, and although not shown, the permission class is set as in the first embodiment. Yes, by giving the day of the week, the time zone, the call time and the permission class, the trunk route table (LCR route table) that meets these conditions can be selected and read in order as the table for giving the cheapest route. It has become.

FIG. 11 is a "trunk route table (LCR route table)" which is referred to when dialing from an extension telephone to a certain area (a certain long-distance communication area).
The station line to be used when making a call, the dial information content to be changed, etc. are preset, and the station line trunk of the station line set here is captured, and the outgoing extension is set according to the dial information content to be changed. By controlling the portion of the dial information from (1) to be changed and sending it to the office line trunk, it is possible to secure the line on the selected cheapest route.

In the "trunk route table (LCR route table)" of FIG. 11 used in the second embodiment, the information of the group of station lines showing the best station line is at the top, and the best station line and communication quality are shown. Information about second best station line groups similar in terms of plane and standard is registered in order, and whether or not to use the second best station line group can be set by a flag.

FIG. 12 is a "accommodating station line trunk status information storage table" storing the vacancy / blockage information of the station line group. The station lines accommodated in the own switching node are the stations in the station line group for each line type. When even one line is vacant, the table is updated and controlled by the control unit 14 so that it is displayed as vacant, and each table is provided in the storage unit 15 in the own exchange node.

FIG. 13 is a flow chart showing the processing procedure until the cheapest route is selected, and explains the flow of this embodiment. Explaining with reference to the figure, first, from an extension telephone accommodated in a certain switching node, a station line originating special number and a called subscriber number (or a cheapest route function special number and a called subscriber number (which called party join Dial the person code (including the area code)) (S21).

Then, the control unit in the exchange node accommodating the originating extension telephone exchanges with the originating ground based on the dial information (information indicating the long-distance call area of the called party, in this case, the area code). The table number of the trunk route corresponding to the calling time zone and the calling day based on the clock function and calendar function of the control unit in the node is obtained from the "route selection table" (S22).

Then, the trunk route table (LCR
When the route table number is obtained, the trunk line table (LCR route table) corresponding to the obtained table number is used to know the station line group to be used, and the "accommodation" in which the vacancy / blockage information of the station line group is stored. The station line trunk status information storage table "(FIG. 12) is referred to check the availability of the station line group to be used in the own exchange node (S2).
3). Information about the availability of the central office line group is sequentially exchanged from each exchange node, and the latest information can be known within the own exchange node. As a result of checking the availability of the station line group to be used,
If there is a free space, the route selection process ends (S2).
4, S29).

Then, the control unit captures an empty one of the station line trunks connected to the station line group in the own exchange node, and shows the portion of the dial information from the originating extension telephone that needs to be changed as shown in FIG. Modify according to the table and send it to the seized trunk line trunk. When the line on the network side is secured and the partner terminal responds, the self-switching node secures the speech path and enables the speech.

On the other hand, if there is no free space in step S24, the flag of the trunk route table (LCR route table) is checked (S25). Then, it is checked whether the flag is on or off (S2
6) If it is on, the process returns to step S23, and the above-described processing starting from this step is repeated. If it is off, it is checked whether or not there is an empty station line group corresponding to the station line group to be used in another exchange node (S27S). , 28), and if there is a vacancy, the route selection process ends (S29).

Then, the control unit in the own exchange node performs a predetermined control so as to bypass the route of the outgoing extension telephone to the other exchange node having the vacancy, and the other exchange node serving as the bypass route uses the above-mentioned use. Dialing information that captures an office line trunk connected to a free office line corresponding to the power station line group, and has made the necessary changes from the exchange node that accommodates the above-mentioned outgoing extension telephone (of the dialing information from the outgoing extension telephone,
The part that needs to be changed is changed according to the table of FIG. 11) and sent to the acquisition station line trunk. If the line on the network side is secured and the other terminal responds, the above-mentioned extension telephone set is the self-switching node and station.
A call can be made through the communication path secured through the optical loop and the above-mentioned other switching node. If there is no free space in step S28, the process returns to step S23, and the above-described processing starting from this step is repeated.

Incidentally, When using a free line of another switching node (when making a detour to another switching node), apply the cheapest route to the highest one, and use the next-best cheapest route when it is not available. The control unit of the source extension accommodation switching node shall function.

As described above, according to the present embodiment, a plurality of extension lines and a plurality of office lines can be accommodated, a plurality of private branch exchanges (switch nodes) each having a central control unit for performing call control, and a high-speed communication path. A switching system connected via a line, and when a call is made from an extension line to a central office line, if all the exchange-accommodating central office lines of the type corresponding to the line type used for the call are blocked, the same type as the line type If there is a vacancy in the central office line accommodating other exchanges, it is possible to use it, and at the time of making a call from the extension accommodated in any of the private branch exchanges to the central office line, at least the outgoing ground and the outgoing time , To the network in order to secure the cheapest route and the group of station lines that can be transmitted by the cheapest route that can be used at that time based on the transmission date information (day of the week or weekday / holiday element) Place to send Refer to the table (LCR route table) that allows you to obtain the information for converting into dial information according to the priority order, and give priority to the station line with the highest priority order for the obtained cheapest route. If the station line is secured, the dial information of the outgoing extension is changed and sent to the network so that the dial information of the cheapest route is sent from this station line to the network. Also, when there is no central office line for the use of the cheapest route, it is ensured to use the central office line of another exchange, and the dialing information required for using the cheapest route is sent out by using the central office line to make the extension extension. In the exchange system in which the lowest cost route is used to connect to the receiving side, if there is no free central office line available for use of the lowest cost route in the exchange that accommodates the outgoing extension to the central office line, In which utilize self intraswitch free office line to be subjected to the use of the cheapest route to be interim suboptimal priorities, both when not available, and configured to use the office line of other exchanges in accordance with the.

Therefore, when trying to use the cheapest route, in the exchange containing the extension transmitted to the office line,
If there is no free station line available for the cheapest route connecting the extension to the other party trying to communicate, by setting,
For the time being, use the station line that can be used for the second-best route with the lowest cost, and use the line of another exchange because it can be controlled to use the line of the other exchange for the first time when there is no available line Therefore, it is possible to suppress an increase in traffic on the communication path due to the use of the communication path between the exchanges (nodes).

Therefore, according to the present invention, it is composed of a plurality of switching nodes, and when a call is made from an extension to a station line, the cheapest route is selected, and the station line available for use of the selected cheapest route is the transmission extension. When it is not in the switching node accommodating the, the switch to the use of the next-best cheapest route, the station line in the accommodating switching node of the transmission extension,
Since it is possible to cover as much as possible, and when there is no station line available for the next-best route, or when there is no sub-optimal route, it is possible to detour to the station line of another exchange node and use it. The ratio of communication across nodes is reduced, which enables smooth transmission to the central office line and connection of extension calls, and does not hinder system operation.

Although various embodiments have been described above, the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications may be made without departing from the scope of the invention. Of course.

[0130]

As described above, according to the first aspect of the invention, a private branch exchange system is provided which is capable of selecting an optimum outside line transmission route according to the actual state of an extension telephone and contributing to further reduction of communication costs. Can be provided. Further, according to the second aspect of the present invention, it becomes possible to smoothly make a call to a central office line and connect an extension call, and it is possible to provide a private branch exchange system that does not hinder system operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a call time table for each extension used in the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of a route selection table used in the first embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the first embodiment of the present invention and is a diagram showing a processing flow when an outside line is originated by using the function of selecting the cheapest route.

FIG. 5 is a diagram for explaining the operation of the first embodiment of the present invention, and a diagram for explaining how the cheapest route selection is performed.

FIG. 6 is a view showing an example of a conventional route selection table used for selecting the cheapest route.

FIG. 7 is a diagram for explaining a conventional technique.

FIG. 8 is an overall configuration diagram for explaining a second embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration example of a private branch exchange applied to a second embodiment of the present invention.

FIG. 10 is a diagram showing an example of a route selection table used in the second embodiment of the present invention.

FIG. 11 is a diagram showing an example of a trunk route table (LCR route table) used in the second embodiment.

FIG. 12 is a diagram showing an example of an accommodation station line trunk status information storage table used in the second embodiment.

FIG. 13 is a diagram for explaining the second embodiment and is a flowchart showing a processing procedure until the cheapest route is selected.

FIG. 14 is a diagram for explaining the configuration of a conventional system.

[Explanation of symbols]

 1 ... Exchange main bodies 1a to 1c are exchange nodes (private exchanges) 2-1 to 2-m ... Extension telephones 3 ... Relay stands 4-1 to 4-m ... Private lines and private lines 5-1 to 5-m ... Station line 6 ... Maintenance terminal 11 ... Call path switch 12-1 to 12-n ... Trunk circuit 13-1 to 13-m ... Line circuit (subscriber circuit) 14 ... Control unit (central control device CC), 15 ... Storage unit 16 ... Interface for relay stand 16a ... Interface 17 ... Digital interface circuit 82 ... Optical loop (high-speed communication path) 83a-83c ... Stations 84a-84c ... Extension telephones 85a-85c ... First priority station line group 86a-86c … Second priority station line group.

Claims (4)

[Claims] 1. A charge system accommodating at least an extension line and a station line, and when making a call from the extension line to the station line, a charge system according to conditions such as a calling party, a usage time zone, communication required time, and date factor In a private branch exchange system that has a route selection function that can select and use the most suitable route based on known conditions at least at the time of route selection from among the routes that can be used by multiple types of lines Is provided with holding means for respectively holding information on required communication time per communication based on the communication results of the extension, and when selecting the optimum use route, communication required for the outgoing extension obtained from the holding means is required. A private branch exchange characterized by being provided with control means for using time information as one of the above-mentioned known conditions and selecting and transmitting an optimum route based on these conditions. Stem. 2. The private branch exchange system according to claim 1, wherein the communication time is obtained by statistically processing a time for each use of a station line from the extension. 3. The private branch exchange system according to claim 1, wherein a plurality of communication times can be held according to time of day and weekday holidays. 4. An exchange system in which a plurality of private branch exchanges each accommodating a plurality of extension lines and a plurality of office lines and each having a control means for performing call control are connected via a high-speed communication path. When making a call to a central office line, when all the local exchange accommodating station lines of the type corresponding to the line type used for the call are closed, and there is a vacancy in the other exchange accommodating station line of the same type as the line type. In addition to making it available, when making a call from an extension housed in any of the private branch exchanges to a central office line, at least the originating destination, the originating time zone, and the originating date information (day of the week or holiday weekdays, etc. Of the station lines that can be transmitted on the cheapest route available at that time, and the information for converting to the necessary dial information sent to the network to secure the cheapest available route Priority In the lowest cost route selection control means obtained according to the rank, the station line to be used for the obtained lowest cost route is secured by giving priority to the station line with the highest priority, and if the station line is secured, from this station line If necessary, change the dial information of the outgoing extension to send it to the network so that it becomes the dial information of the cheapest route to be sent to the network, and if there is no station line to use the cheapest route, other In an exchange system that secures to use the central line of the exchange, sends dial information required to use the cheapest route using that line, and connects the outgoing extension to the called side by the cheapest route, Each of the private branch exchanges is provided with a holding means for holding each piece of communication required time information based on the communication history of the extension for each extension, and the control means has
When selecting the optimum use route, the communication required time information of the transmission extension obtained from the holding means is used as one of the known conditions, and the function of selecting and transmitting the optimum route based on these conditions is provided. A private branch exchange system characterized by being provided and configured.