JPH0715516A - Private branch exchange - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to accurately detect the start of a call without depending on the notification of the other party. [Structure] Trunk circuit 12-1 ~ after sending dial information
At 12-m, tones that arrive via the station lines 2-1 to 2-m are detected, and the pattern recognition means 19a measures the time with tone and the time without tone. . Then, the call start determining means 19b compares the pattern in the first cycle with the pattern recognized in the subsequent cycles, and determines that the repeated pattern, that is, the ringback tone has arrived as long as they match. When the pattern different from the pattern of the first cycle is detected, the stop of the repeating pattern, that is, the stop of the ringback tone is detected, and from this, the response of the called terminal, that is, the start of the call is determined.

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 which is connected to another switching network and makes a call to a terminal accommodated in another network based on an instruction from the terminal.

[0002]

2. Description of the Related Art A private branch exchange permits in-call processing such as call time measurement and billing, and provision of in-call service such as hold during a call. In general, a private branch exchange makes a call in the following procedure when an extension terminal gives an instruction to call a terminal accommodated in another network. That is, as shown in FIG. 10, when the extension terminal is first off-hooked and the extension loop is closed, the private branch exchange returns a dial tone to the extension terminal. Then, when the dial information is given from the extension terminal, the private branch exchange closes the loop of the central office line with the central office exchange, listens to the dial tone returned from the central office exchange, and then transfers the dial information to the central office exchange. To do. In response to this, the station exchange calls the called terminal (at the same time, the ring back tone is given to the private branch exchange and the extension terminal), and after the call from the called terminal, the central office exchange and the local exchange switch After the polarity of the office line with the exchange is reversed, it becomes possible to talk between the extension terminal of the caller and the callee terminal.

In such a case, the private branch exchange recognizes that the call is started by reversing the polarity of the central office line, starts the call-in-progress processing, and allows the provision of the call-in-service.

However, some central office switching equipments have specifications that do not notify the other party's response due to polarity reversal or the like, and when making a call through such central office switching equipment, it is detected that a telephone call has started. Can not do it. Therefore, it becomes impossible to permit the start of the processing during a call and the provision of the service during a call.

In order to solve this problem, there is a private branch exchange in which it is considered that a call is started when a predetermined time has passed after the dial information is sent, but it is not possible to accurately specify the start time of the call. , The measurement of call time and call charge becomes extremely inaccurate. In addition, there are problems such as the provision of the busy service is permitted when the provision of the busy service is not preferable, or the provision of the busy service is not permitted even if the busy service must be provided. It was

[0006]

As described above, the conventional private branch exchange cannot accurately detect the start of a call unless the other party's response notification is given from the exchange of the connected network, and the processing during the call or There was a problem that the service during a call could not be performed accurately.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a private branch exchange capable of accurately detecting the start of a call regardless of the notification of the response from the other party. Especially.

[0008]

To achieve the above object, a first invention is a tone detecting means such as a trunk circuit for detecting a predetermined tone coming through an outside line such as a station line, Pattern detecting means such as pattern recognizing means for detecting the pattern of the presence or absence of the tone for each cycle based on the detection result of the tone detecting means;
A storage unit such as a storage unit that stores the pattern detected by the pattern detection unit is provided, and the response detection unit such as the call start determination unit sends the dial information to the outside line. The latest pattern detected by the pattern detection unit is compared with the past pattern stored in the storage unit, and if the patterns do not match, it is determined that the call destination terminal has responded.

A second aspect of the present invention is the response detecting means according to the first aspect of the present invention, in which the pattern in the first cycle after the dial information is transmitted is different from the pattern in the next cycle. The pattern was not used for judgment.

A third aspect of the present invention is the response detecting means according to the first aspect of the present invention, wherein when the tone detecting means does not detect a tone before a predetermined time elapses after the dial information is transmitted, the call destination is called. It was decided to judge that the terminal of replied.

[0011]

According to the first aspect of the present invention, the predetermined tone coming through the outside line is detected by the tone detecting means, and the pattern of the presence or absence of the tone is detected by the pattern detecting means every cycle based on the detection result. To be done. The detected pattern is stored in the storage means, and after the dial information is sent to the outside line by the response detection means, the latest pattern detected by the pattern detection means is stored in the storage means. Is compared with the pattern in the past stored in, and if they do not match, it is determined that the call destination terminal has responded. Therefore, the response of the called terminal, that is, the start of the call is determined by the state of the predetermined tone.

According to the second aspect of the invention, the response detecting means determines the pattern in the first cycle when the pattern in the first cycle after sending the dial information is different from the pattern in the next cycle. Not used for. Therefore, if the leading edge of the pattern is missing in the first cycle, the pattern of this cycle is not used for determining the response of the call destination terminal.

Further, according to the third aspect of the invention, in the response detecting means, if no tone is detected by the tone detecting means until a predetermined time elapses after the dial information is transmitted, the terminal of the call destination is It is determined that it has responded. Therefore, when the predetermined tone does not arrive, it is determined that the terminal of the call destination has responded when the predetermined time has elapsed after the dial information was transmitted.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a functional block diagram showing a main configuration of a private branch exchange according to an embodiment of the present invention. In the figure, the one indicated by 1 is a private branch exchange. This private branch exchange 1
Call path switch 11, trunk circuits 12-1, 12-2 ..., 12-
m, line circuits 13-1, 13-2 ..., 13-n, tone sending circuit 1
4, reception board interface circuit (reception board IF circuit) 1
5, maintenance terminal interface circuit (maintenance terminal IF circuit)
An external storage interface circuit (external storage IF circuit) 17, a storage unit 18, and a central control unit 19 are provided, and a speech path switch 11, trunk circuits 12-1 to 12-m, line circuits 13-1 to 13- are provided. n, tone sending circuit 14, reception board interface circuit 15, maintenance terminal interface circuit 1
6, external storage interface circuit 17 and storage unit 18
Is connected to the control unit 19 via a bus.

The call path switch 11 includes a trunk circuit 12
-1 to 12-m, line circuit 13-1 to 13-n, tone sending circuit 14
And a reception board interface circuit 15 are connected to each other, and under the control of the control unit 19, any two of them are exchange-connected to each other.

The trunk circuits 12-1 to 12-m are connected to station lines 2-1, 2-2, ..., 2-m, respectively, and these station lines 2-1 to 2-m are connected.
Is further connected to a network (not shown). The trunk circuits 12-1 to 12-m perform station line interface operations such as monitoring the status of the station lines 2-1 to 2-m and transmitting various signals to the network. Control information relating to the above-mentioned station line interface operation is exchanged.
The trunk circuits 12-1 to 12-m have a function of detecting tones of a predetermined frequency arriving via each of the office lines 2-1 to 2-m and notifying the central control unit 19 of the detection result. Have.

Each of the line circuits 13-1 to 13-n has an extension line.
3-1, 3-2, ..., 3-n are connected, and extension terminals 4-1, 4-2, ..., 4-n are further connected to the extensions 3-1 to 3-n. The line circuits 13-1 to 13-n perform extension interface operations such as monitoring the status of the extensions 3-1 to 3-n and sending various signals to the extension terminals 4-1 to 4-n, and control Control information relating to the extension interface operation is exchanged with the section 19.

The tone sending circuit 14 generates and outputs various tone signals such as ring back tone and busy tone under the control of the control unit 19. A reception board 5 is connected to the reception board interface circuit 15 and performs an interface operation with the reception board 5.

The maintenance terminal 6 is connected to the maintenance terminal interface circuit 16 and performs an interface operation with the maintenance terminal 6. The maintenance terminal 6 is used by a maintenance person to check the state of the private branch exchange 1 and change various settings.

An external storage device 7 is connected to the external storage interface circuit 17 and performs an interface operation with the external storage device. The external storage device 7
Is a floppy disk drive, a hard disk drive, or the like, and is for saving the information stored in the storage unit 18 and storing the operation record of the private branch exchange 1.

The storage unit 18 is composed of a ROM and a RAM, stores control programs and system data for the central control unit 19, and is used by the central control unit 19 to store various data.

The control unit 19 includes, for example, a microcomputer as a main control circuit, and has pattern recognition means 19a and call start determination means 19b in addition to well-known general control means in a private branch exchange. ing. Of these, the pattern recognition means 19a is for recognizing the tone pattern based on the result of the tone detection in the trunk circuits 12-1 to 12-m. The call start determination means 19b determines the start of a call based on the recognition result of the pattern recognition means 19a.

Next, the operation of the private branch exchange having the above-described structure when a call is made from the extension terminal through the office line is shown in FIG. 4 and FIG. Description will be given with reference to a sequence diagram.

First, any of the extension terminals 4-1 to 4-n (herein, described as the extension terminal 4-1) is off-hooked, and the corresponding extension (here, the extension 3-1) is set as shown in FIG. When the loop is closed, the central controller 19 sends a dial tone to the extension terminal 4-1 which is off-hook (step 2a in FIG. 2). This is the tone sending circuit 1
The dial tone generated in 4 is used as the call path switch 11,
It is sent out via the line circuit 13-1 and the extension 3-1.

The operator of the extension terminal 4-1 goes off-hook as described above, listens to the dial tone, and then dials the telephone number of the called terminal. Then, the extension terminal 4-1 sends the dial information corresponding to the telephone number dialed to the extension 3-1. This dial information is given to the central control unit 19 via the extension 3-1 and the line circuit 13-1.

After transmitting the dial tone in step 2a, the central control unit 19 waits for the dial information to arrive (step 2b). When the dial information is given as described above, this After analyzing the dial information, an appropriate station line (herein, described as station line 2-1) is captured and the loop is closed (step 2).
c).

The central office (not shown) of the network to which the central office line 2-1 is connected is shown in FIG. 4 for the central office line 2-1 when the central office line 2-1 is closed. To send dial tone. The trunk circuit 12-1 detects this and notifies the central control unit 19 that a dial tone has arrived.

Now, the central control unit 19 waits for a dial tone to arrive after capturing the office line 2-1 in step 2c (step 2d), and when the dial tone is given as described above, The dial information is sent to the office line 2-1 via the trunk circuit 12-1 (step 2).
e).

Upon receiving the dial information sent from the private branch exchange 1, the central office exchange sends a call signal to a terminal (callee terminal) indicated by the dial information among the accommodated terminals (not shown). Send out. At the same time, the central office exchange sends a ringback tone to the central office line 2-1. This ringback tone is sent to the extension terminal 4-via the private branch exchange 1.
Passed to 1.

When the call destination terminal responds in this state, the central office switch stops sending the ringing signal and ring back tone, and connects the call destination terminal to the office line 2-1. Thus, the extension terminal 4-1 and the call destination terminal are connected via the extension 3-1, the private branch exchange 1, the central office line 2-1 and the central office exchange, and a call state is established as shown in FIG.

By the way, the central control unit 19 sends the dial information in step 2e, and then performs a call start determination process (step 2f). This pattern recognition process is performed as follows.

First, it is judged whether or not a tone is detected by the trunk circuit 12-1 within a predetermined time after sending the dial information (steps 3a and 3 in FIG. 3).
b) When the tone is detected, the measurement of the tone present time is started (step 3c).

Subsequently, the central control unit 19 controls the trunk circuit 12
It waits until the tone is no longer detected by -1 (step 3d), and when the tone is no longer detected, the measurement of the tone present time is ended (step 3e) and the measurement of the no tone time is started (step 3f).

Then, the central control unit 19 waits until the tone is detected again by the trunk circuit 12-1 (step 3g). When the tone is detected, the no-tone time is measured. Finish (Step 3)
h).

Through the above processing, the central control unit 19 determines the magnitude of the period during which the tone has arrived (the period with the tone) (the period with the tone) and the tone that exists immediately after this period with the tone. The size of the non-tone period and the non-tone period are measured respectively.

By the way, as shown in FIG. 5, the ring back tone transmitted by the central office repeats a pattern for one cycle consisting of a period with a tone and a period without a tone. Assuming that the period with tone is 1000 ms and the period without tone is 2000 ms, in the first cycle after sending the dial information, the result with tone = 1000 ms and the period without tone = 2000 ms is obtained. In this way, the pattern for one cycle of the incoming tone is recognized in the form of the tone period and the tone-free period.

After the measurement of the time with tone and the time without tone for one cycle is completed, the central control unit 19 judges whether or not the measured cycle is the first cycle after sending the dial information (step 3i). ).

When the period measured here is the first period after the dial information is transmitted, the central control unit 19 recognizes this time (the tone presence time and the tone absence time of the first period).
Is stored in the storage unit 18 as a reference pattern as shown in FIG. 6 (step 3j). And after this, step 3
The processing after b is repeated to measure the time with tone and the time without tone in the second cycle.

After the measurement of the time with tone and the time without tone in the second cycle is completed, the central control unit 19 shifts the processing from step 3i to step 3k and stores the recognition result of the second cycle in the storage unit 18. It is compared with the stored reference pattern (time with and without tone in the first cycle) (step 3k), and as a result of the comparison, whether the recognition result in the second cycle and the reference pattern match or not. A judgment is made (step 3l).

Here, as shown in FIG. 5, when all ringback tones have arrived in the second cycle as well, in the second cycle, the result of tone presence time = 1000 ms and tone absence time = 2000 ms is obtained. . Therefore, the recognition result of the second cycle matches the reference pattern. In this way, when the latest recognition result and the reference pattern match, the central controller 19 repeats the processing from step 3c. As a result, the same processing as in the second cycle is repeated for the subsequent cycles.

However, in the case of the 4th cycle shown in FIG. 5, the result that the tone present time = 1000 ms and the tone not present time = 500 ms is obtained. Therefore, the recognition result of the fourth cycle does not match the reference pattern. When the latest recognition result does not match the reference pattern in this way, the central control unit 19 determines that the call is started, and ends the call start determination process. When the central control unit 19 finishes the call start determination process,
In-call processing is started and at the same time the in-call service is allowed to be provided.

On the other hand, if the tone does not arrive even after the lapse of a predetermined time after the dial information is transmitted, the central control unit 19 determines that the call is started, and ends the call start determination process. In addition, in the call start determination process described above, step 3
The steps c to 3h are processed by the pattern recognition means 19a, and the other steps are processed by the call start determination means 19b.

Thus, according to the present embodiment, the tone-present period and the tone-absence period immediately after arrival of the dial information are set as one cycle of the ringback tone, and the pattern is the tone-present time and the tone-free period. Recognize in the form. If it is a ring back tone, this pattern is repeated. Therefore, the pattern of the subsequent cycle is similarly recognized, and it is judged whether or not the same pattern is repeated by comparing with the pattern of the first cycle. It is possible to determine whether or not the ringback tone has arrived. Then, as described above, if the called terminal responds, the central office switch stops sending the ringback tone, so by detecting that the ringback tone has stopped due to the occurrence of different pattern patterns, the calling It is possible to detect that the destination terminal has responded.

Further, even if the ring back tone does not arrive when the center exchange does not send the ring back tone or when the called terminal responds immediately before the center exchange sends the ring back tone, the dial information is sent. It is possible to detect that the called terminal has responded after a predetermined time has passed. It should be noted that this predetermined time is a very short time since the time required for the ringback tone to arrive after the dial information has been transmitted when the central office switch transmits the ringback tone is a very short time, and there is an extremely small error in the call destination. It can detect that the terminal has responded.

As described above, it is possible to accurately detect that the called terminal has responded, even if the central office switch has not notified the other party's response (polarity inversion) or has not transmitted the ringback tone. You can Therefore, from the time when the called terminal responds, that is, when the call starts,
It is possible to accurately start the acceptance of the processing during the call and the provision of the service during the call.

(Second Embodiment) By the way, in the ring back tone transmitted from the central office, the tip of the tone may be missing in the first cycle. In such a case, since the pattern in the first cycle and the pattern in the subsequent cycles are different, if the pattern of the first cycle is used as the reference pattern as in the above-described first embodiment, the ringback tone continues in the second cycle. Even though I am doing it, it is decided that the call has started.

Therefore, if the ring back tone sent from the central office switch may have a missing tip at the beginning of the tone, the call start determination process of the central control unit 19 may be changed as follows.

FIG. 7 is a flow chart showing the processing procedure of the call start determination processing of the central control unit 19 in this embodiment. The same parts as those in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

The difference between this embodiment and the first embodiment is whether or not the recognition result compared with the reference pattern is the second cycle when it is determined in step 3l that they do not match. The point is that the determination (step 7a) is performed. If the recognition result compared with the reference pattern is for the second cycle, the recognition result for the second cycle is stored in the storage unit 18 as a reference pattern in step 3j as shown in FIG. By repeating the process, the recognition results of the third and subsequent cycles are compared with the recognition results of the second cycle. That is, if the recognition result of the first cycle and the recognition result of the second cycle are different, the reference pattern is updated to the recognition result of the second cycle. And 3
If the recognition result after the cycle and the reference pattern match,
This is determined to be a call start, and the call start determination process is ended.

Thus, according to the present embodiment, when the tone lacks in the first cycle as shown in FIG. 8, this recognition result is not used for the judgment of the start of the call, and the recognition in the second cycle is performed. A call start is determined using the result as a reference pattern. As a result, even if the ringback tone sent from the central office switch may be missing the tip of the tone in the first cycle, the above-mentioned erroneous detection does not occur, and the call starts more accurately. Can be detected.

The present invention is not limited to the above embodiments. For example, response notification such as polarity reversal may be detected, and if this response notification can be detected, it may be determined that the call has started.

Further, in each of the above embodiments, one cycle of the ringback tone is assumed to consist of one tone present period and one tone non-existing period, and the pattern is recognized by measuring the respective periods. However, the ringback tone pattern in which one tone period includes a plurality of tones is measured by measuring each time of a plurality of tones periods and a plurality of no tones period following each of the plurality of tones periods. May be detected.

Further, it is not necessary to perform the call start judgment shown in each of the above embodiments for all of the office lines 2-1 to 2-m.
For some of 2-1 to 2-m, the call start determination may be performed based on the other party's response notification as in the conventional case.
This is convenient if it can be selectively set from the outside by a maintenance terminal or the like.

In the second embodiment, when the recognition result of the first cycle and the recognition result of the second cycle are different from each other, the recognition result of the second cycle is used as the reference pattern. The result may be unconditionally used as a reference pattern.
In addition, various modifications can be made without departing from the scope of the present invention.

[0055]

According to the first aspect of the invention, tone detecting means such as a trunk circuit for detecting a predetermined tone coming through an outside line such as an office line, and the tone detection means based on the detection result of the tone detecting means. Pattern detecting means such as a pattern recognizing means for detecting the presence / absence pattern for each cycle, and storage means for storing the pattern detected by the pattern detecting means, such as a storage section, are provided.
For example, in response detection means such as a call start determination means, after sending dial information to the outside line, the latest pattern detected by the pattern detection means,
By comparing with the past pattern stored in the storage means, and when they do not match, it is determined that the terminal of the call destination has responded, so that it is determined that the ringback tone, which is a periodic signal, has stopped. By detecting it, it is possible to detect that the terminal of the call destination is responding, and thereby the private branch exchange can accurately detect the start of the call regardless of the notification of the response from the other party.

A second aspect of the present invention is the response detecting means according to the first aspect of the present invention, in which the pattern in the first cycle after the dial information is transmitted is different from the pattern in the next cycle. Since the pattern is not used for the judgment, even if there is a loss in the first cycle of the ringback tone, it is possible to detect the stop of the ringback tone without being affected by this and to notify the other party's response. It becomes a private branch exchange that can accurately detect the start of a call without depending on it.

Furthermore, a third aspect of the present invention uses the response detecting means of the first aspect of the invention when the tone detecting means detects no tone until a predetermined time elapses after the dial information is transmitted. Since it is determined that the terminal responds, the private branch exchange can accurately detect the start of the call even when the ringback tone does not arrive.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a main configuration of a private branch exchange according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of a central control unit 19 when making a call via an office line.

FIG. 3 is a flowchart showing a processing procedure of a central control unit 19 at the time of call start determination processing in the first embodiment.

FIG. 4 is a sequence diagram showing a state of signal exchange between a private branch exchange, a central office exchange, an extension terminal and a callee terminal.

FIG. 5 is a diagram showing an example of a state of an incoming ringback tone in the first embodiment.

FIG. 6 is a reference pattern storage unit 18 in the first embodiment.
FIG. 6 is a diagram schematically showing a storage state in the storage device.

FIG. 7 is a flowchart showing a processing procedure of a central control unit 19 at the time of call start determination processing in the second embodiment.

FIG. 8 is a diagram showing an example of a state of an incoming ringback tone in the second embodiment.

FIG. 9 is a reference pattern storage unit 18 in the second embodiment.
FIG. 6 is a diagram schematically showing a storage state in the storage device.

FIG. 10 is a diagram illustrating a conventional technique.

[Explanation of symbols]

1 ... Private branch exchange 11 ... Call path switch 12-1 to 12-m ... Trunk circuit 13-1 to 13-n ... Line circuit 14 ... Tone sending circuit 15 ... Reception board interface circuit (reception board IF circuit) 16 ... Maintenance terminal Interface circuit (maintenance terminal IF circuit) 17 ... External storage interface circuit (external storage IF circuit) 18 ... Storage unit 19 ... Central control unit 19a ... Pattern recognition means 19b ... Call start determination means 2-1 to 2-m ... Station line 3-1 to 3-n ... extension 4-1 to 4-n ... extension terminal 6 ... maintenance terminal 7 ... external storage device

Claims (3)

[Claims] 1. In a private branch exchange to which an outside line connected to another switching network is connected, tone detecting means for detecting a predetermined tone coming through the outside line, and based on a detection result of this tone detecting means, Pattern detection means for detecting the pattern of the presence or absence of the tone for each cycle; storage means for storing the pattern detected by the pattern detection means; and after sending dial information to the outside line,
The latest pattern detected by the pattern detection unit is compared with a past pattern stored in the storage unit, and if the patterns do not match, it is determined that the call destination terminal has answered. A private branch exchange characterized by the above. 2. The response detecting means does not use the pattern in the first cycle for determination when the pattern in the first cycle after sending the dial information is different from the pattern in the next cycle. The private branch exchange according to claim 1. 3. The response detecting means determines that the terminal of the call destination has responded if no tone is detected by the tone detecting means before a predetermined time elapses after sending the dial information. The private branch exchange according to claim 1.