JPH0698028A - Conference system - Google Patents

Abstract

PURPOSE:To arbitrarily connect the lines of conference participants and echo cancel circuits less than the number of lines so as to flexibly deal with the presence/absence of the necessity of an echo cancel function caused by the conference form or the difference of places where the conference participants are existent, in conference telephone service. CONSTITUTION:Echo cancel circuits 9-1-9-n and a conference telephony device interface part 10 are installed between conference telephone devices 12-1-12-n in a center equipment 6 connected to a conference function installing station and provided with various voice function units and a highway interface part 7. On the other hand, a highway control part 15 is provided to control the connection of lines, and functions are provided by controlling switch control parts 8 and 11 provided at the highway interface part 7 and the conference device interface part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conference telephone system in which a conference telephone device installed in a switchboard, a center station, or the like makes effective control of reverberation noise for conference added voice only when necessary.

[0002]

2. Description of the Related Art Conventionally, in a conference telephone apparatus that employs the N-1 addition method, ringing noise, semi-ringing noise, and reverberation noise due to impedance mismatch at the 2-line to 4-line conversion point, which is a factor of voice degradation, are prevented. Therefore, as shown in Japanese Patent Laid-Open No. 60-226262, an echo canceling device is fixedly mounted on each conference participant circuit regardless of the distance between conference participants and the conference form.

[0003]

In the prior art, as described above, the echo canceling function is fixedly mounted regardless of the form of the conference and the distance between the conference participants. Conference type is N
When there are many conference participants in the -1 addition method and when making a long-distance call, an echo canceling device becomes necessary as the number of conference participants increases due to the influence of the N line loop. It is not necessary when the number of participants in the conference is as small as three or four. In addition, when the conference system is a selective addition system with about three parties, three parties with high audio levels are selected from all the conference participants and added, so except during long distance calls (for example, international conferences). No echo canceling device is required. Therefore, if an echo canceling device is fixedly installed for each conference participant line, an echo canceling circuit is originally installed even for a line that does not require echo cancellation, which increases the cost per line. It is uneconomical, such as an increase in the amount of hardware for the entire conference phone.

Also, when adding a conference telephone device or adding a two-way call service function other than the conference telephone service to a switchboard or a center station, echo canceling circuits are required for the increased lines. Therefore, it is uneconomical for the same reason as above.

An object of the present invention is to provide a means for connecting an echo canceling device for improving voice quality in a conference telephone device as needed, and to construct an economical conference telephone system.

[0006]

In order to achieve the above object, the conference telephone system of the present invention is equipped with an echo canceling circuit which can be inserted / removed between a conference telephone device and a highway interface section, and an echo canceling circuit is provided. When not mounted, a means for autonomously setting the echo canceling unit through and connecting it to the adding circuit on the conference telephone device side is provided. In addition, the conference caller and the highway interface unit are provided with an instruction, via the echo cancel circuit, or not, based on information such as the conference participant number and the conference participant existing position registered in the host service control device in advance. This is provided to each highway connection control unit that switches the communication line.

[0007]

According to the present invention, from the upper center device SCP,
A highway control unit that receives information such as the location of the conference participants and the conference type, a switch control unit that changes the line connection in the highway interface that is controlled thereby, and a switch that changes the line connection in the conference telephone device interface. By providing the control unit, it is possible to arbitrarily connect fewer echo cancel circuits than the number of lines, and compared with existing devices that are fixedly equipped with echo cancel circuits.
The system can be flexibly supported depending on whether or not the echo cancel circuit is necessary.

[0008]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 3 to 5. FIG. 1 is a block diagram of the entire system in the conference telephone system of the present invention. FIG. 3 is a block diagram of a functional configuration in which the echo canceling section is autonomously turned through when the echo canceling circuit is not mounted. FIG. 4 is a block diagram showing the highway interface unit 7, the echo cancellation units 9-1 to 9-n, and the conference device interface unit 10. Figure 5
FIG. 4 is a block diagram showing a voice addition unit in a conference phone device used in a conference phone system. The first and second embodiments will be described with reference to FIGS. 1-1 to 1-n in FIG.
Conference participant lines connected to the subscriber line exchange, 2-1 to 2-1
2-n is a conference participant line directly accommodated in the center exchange, 3-1 to 3-n are subscriber exchanges, and 4-1 to 4-
n is a 2-wire to 4-wire conversion circuit, 5 is a center exchange, and 6
Is a center device which is connected to the center station exchange 5 and has various voice function units. 7 is an upper SCP determined by the conference participant voice data input from the center station exchange 5 from the conference form and the position of the conference participants. According to the control from
A highway interface unit for switching connection for transmission / reception to / from a voice addition unit of the conference telephone device via an echo cancel circuit or not, and a switch control for controlling ON / OFF of a line in the highway interface unit 7. Department. 9-1 to 9-n are echo canceling circuit units, and 10 is an echo canceling circuit unit 9-1 to 9-n.
From the highway interface unit to the voice addition units 13-1 to 13-n through the conference addition device interface unit 11-1 to 13-n. A switch control unit for controlling the switch unit, 12-1 to 12-n are conference telephone devices,
13-1 to 13-n are voice addition circuits, 14-1 to 14
-N is an instruction from the upper SCP regarding the number of participants in the conference, the number of additions to be added, the line to connect to the conference device at another point, the connection control, the voice level information of the other conference telephone device, and the direct communication in the own conference telephone device. After determining the subscribers to be added at the general conference from the accommodated subscriber's voice level information, the instruction is given to the addition circuit, and when the conference mode is N-1 addition, only the own line is turned off to talk. In the case of the person-selected addition method, a voice addition control unit that controls the voice addition units 13-1 to 13-n such that only the line of the addition target speaker is turned on and the others are turned off. Reference numeral 15 denotes a switch control unit 8 in the highway interface unit according to an instruction from the SCP, which is a higher-level device.
And the switch control unit 11 in the conference telephone interface unit
And a highway control unit that controls each of the voice addition control units 14-1 to 14-n. Reference numeral 16 is a level detection circuit for comparing the voice levels of the conference participant line data input to the conference telephone device when the conference mode is the speaker selection system, and selecting a speaker to be added. In FIG. 3, 23
Is a line autonomous switching unit in the highway interface unit 7 when the echo cancellation circuit is not installed, and 24 is
The line autonomous switching unit in the conference device interface unit 10 is shown. Numerals 25 and 30 pass through the voice data from the conference function setting station 5 and the voice addition unit 13 in the conference telephone device 12-1.
-1 is an open / close buffer for connecting to -1, 26 and 31 are open / close buffers for connecting the voice data from the conference function setting station 5 to the echo canceling circuit section, and 27 and 32 are sending from the echo canceling circuit 9-1. Open / close buffer for connecting the received voice data to the conference function installation station 5, 2
Reference numerals 8 and 33 denote open / close buffers for transmitting from the voice addition unit 13-1 to the conference function installation station 5 through the echo cancel circuit 9-1. Reference numerals 29 and 34 control opening / closing of the buffers 25 to 33. It is an AND circuit.

Conference participants 1-1 to 1-n or 2-
The analog voice signals from 1-2 to n are exchange stations 3-1 to 3-1.
2-line to 4-line conversion circuits 4-1 to 4- installed in 3-n
After being input to n, it is converted into a digital voice signal and input to the center exchange 5. Thereafter, the center station switch 5 inputs the voice data to the highway interface section 7 in the center apparatus 6. At this time, when the conference mode is the N-1 addition method, the number of conference participants is large, and in the case of a long-distance call, an echo canceling device is required due to the influence of the loop. In the conventional conference telephone system, as shown in the block diagram of the conventional conference telephone system in FIG. 2, the voice data of each conference participant input from the conference function installation station 5 to the highway interface unit 7 is echo canceling circuit. 9-1 to 9-n, and the voice addition circuits 13-1 to 13-1 in the conference telephone devices 12-1 to 12-n are input.
Input to 3-n. With this configuration, as described above, even in a conference mode that originally does not require an echo cancel circuit, the echo cancel circuit is fixedly mounted, so the cost per line increases due to an increase in the hardware amount of the entire conference telephone device. , Becomes uneconomical. Therefore, in the conference telephone system of the present invention, as shown in FIG. 1, the detachable echo canceling circuits 9-1 to 9-n are provided between the highway interface unit 7 and the conference telephone devices 12-1 to 12-n. The echo canceling circuit is provided with a function of switching the line between an echo canceling function and a non-cutting line according to the necessity of the echo canceling circuit according to an instruction from the host SCP. In FIG. 3, when the echo cancel circuit is installed, the AND circuits 29 and 3 are determined according to the AND condition between the valid value of +5 V due to the insertion of the echo cancel circuit and the valid value from the highway controller 15.
The output value of 4 becomes a valid value, the open / close buffers 26 and 27 are opened, and the communication line is routed through the echo cancel circuit. If not installed, AND circuits 29, 3
1 input to 4 becomes invalid value and open / close buffer 25, 28
Open and make it through. Third and fourth embodiments will be described with reference to FIGS. 1, 4 and 5. Before the conference is held, the service control device (SCP), which is the host device of the center device, determines the conference type, the position of each conference participant, the conference time, the number of conference participants, the participant number, the number of additions selected, and the number of other points. The information such as the line number connected to the conference device is obtained, and based on the information, the SCP adds N-1 to the voice data input to the highway interface unit 7 in the case of a long-distance speaker or in the conference mode. In the case of the method (multi-person), it is connected to the echo canceling unit, and in the case of a short-distance speaker, or in the case of a short-distance speaker and the conference mode is the N-1 addition method (small number of people),
Through connection to the voice addition units 12-1 to 12-n, control of connection switching of the communication line is performed by the switch control unit 8 in the highway interface unit 7 and the conference telephone device interface unit 1.
The switch control unit 11 in 0 controls the switch unit 17 and the switch unit 20. The voice data input to the echo cancel circuit 9-1 is adaptive filter 18
Then, the echo component is suppressed by subtracting a pseudo echo created based on the data from the voice data to which the echo is added by the attenuator 19. The voice addition data from which the echo component has been removed is input to the highway interface unit 7, and the switch control unit 8 connects the line. After that, the audio is distributed to each conference participant.

In FIG. 5, when the conference mode is the N-1 addition system, the switch unit 21 is turned off only for the own line in the conference telephone unit 12-1 and the switch units for other lines are turned on to make voice data. Is added. When the conference mode is speaker selection, the voice level detection circuit 2 detects a speaker with a high voice level, inputs information to the highway control unit 17, and transmits the information to the voice addition control unit 14-1 in FIG. , The switch unit 21 is controlled. The information on the conference form is determined by the service management device as described above.

[0011]

In the conference call system, the echo canceling device can be inserted and removed, and when not mounted, the echo canceling section is autonomously connected to the adder circuit by making the echo canceling unit through, and when mounted, the conference call participant An instruction to pass or not to pass through the echo cancel circuit is given to each line from the host device, and it is possible to flexibly cope with whether or not the echo cancel circuit is necessary depending on the difference in the speaker presence position of the conference participants. Further, it is possible to suppress an increase in cost per line and provide an economical echo cancellation control function.

[Brief description of drawings]

FIG. 1 is a block diagram of a conference phone system according to the present invention.

FIG. 2 is a block diagram of a conference call system in the related art.

FIG. 3 is a functional block diagram in which an echo cancel circuit is not installed and autonomous through is performed.

FIG. 4 is a functional block diagram of a highway switching unit.

FIG. 5 is a block diagram of a voice addition unit.

[Explanation of symbols]

7 ... Highway interface section, 8 ... Switch control section, 9-1 to 9-n ... Echo cancellation circuit section, 11 ...
Switch control unit, 14-1 to 14-n ... Voice addition control unit, 15 ... Highway control unit

Claims (5)

[Claims] 1. A two-line to four-line conversion in a conference telephone system in which a plurality of subscribers are connected to a conference telephone device installed inside a subscriber exchange or in a centralized center outside the exchange to make a telephone call by a plurality of parties. A conference call system with an echo canceling function that can be inserted and removed by the service control function to prevent echoes that may occur due to wraparound at points. 2. In the conference telephone system according to claim 1, when the echo canceling unit is not mounted, the echo canceling unit is autonomously provided with means for connecting the adding circuit with the echo canceling unit being through. A conference phone system that can be used without changing the hardware or software configuration when functions are not required. 3. The conference telephone system according to claim 1, wherein the conference participation system (N-1 addition system, speaker selective addition) and the presence position of the speaker (short-distance call, long-distance call) participate in the conference. A conference phone system that allows the caller's communication line to be switched via the echo canceler or not via an instruction from the host controller. 4. The conference telephone system according to claim 3, wherein a highway interface unit for receiving a command from a host controller and arbitrarily connecting a line of a conference participant and an echo canceling circuit smaller than the number of lines is provided. Switch control unit, switch control unit in the conference telephone device interface,
A conference call system that has a voice addition control unit in the conference call device. 5. A conference telephone system comprising a combination of a plurality of functions according to claims 1 to 4.