JPH07288492A - Order device - Google Patents

Abstract

PURPOSE:To evade the occurrence of howling in a duplex communication system by comparing the control information that is received through a circular transmission line and separated from it with the selection information and then performing the fine/rough switching of acoustic connection between the receiver and transmitter means according to the result of comparison. CONSTITUTION:When the operator of a transmission device 21, closes a contact 291 for arrangement, the message of the operator is amplified by an amplifier 251 and coded by a coding means 261. An amplifier 281 is stopped and an ID processing part sets the ID value at [01]. A multiplexing part 231 multiplexes the coded voices and the ID and sends them to a circulr network 42. The ordering person who heard the message via a transmission device 213 closes a contact 293. Thus an ID processing part 273 changes the ID value to [10] and gives an answer. The device 211 recognizes this answer and actuates again the amplifier 28. so that a fully double communication channel is formed between both devices 211 and 213. When the contact 291 is opened after arrangement, the device 211 resets the ID value at [00] and restarts the relay processing. When the arranger opens the contact 293, all operations are reset in each holding state. Meanwhile a speaker 451 is driven only in a contact open state and therefore the occurrence of howling is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meeting device which is arranged adjacent to a transmission line formed in an annular shape and which forms a telephone line required for a meeting through the transmission line.

[0002]

2. Description of the Related Art A ring network (hereinafter referred to as "ring network")
Say. ) Generally has a short total length of a transmission line and a detour may be formed at the time of failure, but between non-adjacent nodes, a communication line is formed under the relay processing by each node located between these nodes. Therefore, the transmission efficiency is lower than that of the star network.

Therefore, such a ring network is often adopted as a small-scale communication network such as a private network or a local area network provided for a specific service so that the above disadvantages can be ignored.

FIG. 4 is a diagram showing a configuration example of a conventional ring network. In the figure, transmission devices 41 _{1 to} 41 ₄ are arranged adjacent to each other on a ring network 42 and individually connected to telephone terminals 43 ₁ to 43 ₁ .
The microphones 44 _{1 to} 44 ₄ and the speakers 45 ₁ to _{4 4} which accommodate the microphones 43 ₄ and are used for the meeting via the order wire.
5 has a _4.

[0005] Such transmission devices 41 _{1 to} 41 ₄ have a predetermined number of lines based on the traffic distribution of these transmission devices and business communication (meeting) related to operation.
For the order wire reserved for
The demultiplexing process is performed at the connection point with the two outgoing routes, and the multiplexing process is performed at the connection point with the incoming route of the ring network.

Furthermore, the transmission device 41 ₁ to 41 ₄ performs call processing for a transit call calls the annular network 42 relating to the telephone terminal 43 ₁ to 43 _4, and performs the same call processing for the order wire.

The transmission device 41 ₁ uses the microphone 44 ₁ when transmitting to a specific transmission device (herein, for simplicity, indicated by reference numeral “41 ₃ ”) via the order wire. Encodes the transmitted audio signal,
Further, the above-mentioned multiplexing processing is performed and the result is sent to the ring network 42. In cyclic network 42, the transmission information, for simplicity, as shown by the arrows in FIG. 4, the transmission device 41 _1, 4
It is assumed that the data is transmitted in one direction shown in the order of 1 ₂ , 41 ₃ , 41 ₄ , 41 ₁ , ...

The transmission device 41 ₂ separates and decodes the thus multiplexed audio signal and supplies the audio signal obtained by the decoding to the speaker 45 ₂ and
Encoding and multiplexing are performed based on the procedure of the call processing described above, and the result is sent to the ring network 42 (hereinafter, such a series of processing is referred to as "relay processing").

The transmission devices 41 ₃ and 41 ₄ similarly perform such relay processing, and the transmission devices 41 _{2 to} 41 ₄
Voice call messages are sent from the speakers 45 _{1 to} 45 _4, respectively.

In the transmission device 41 ₃ , when a person in charge of maintenance or other person responds via the microphone 44 ₃ , the voice signal given from the microphone is encoded in place of the voice signal to be the subject of the above-mentioned relay processing. And is multiplexed and sent to the ring network 42. The transmission device 41 ₁ takes in such an audio signal by the relay processing continued by the transmission device 41 _4, performs separation and decoding processing, and gives it to the speaker 45 ₁ .

Therefore, a meeting is held between the transmission devices 41 ₁ and 41 ₃ via the order wire. Note that such an arrangement is not limited to the transmission devices 41 ₁ and 41 _3, and is similarly performed between any two transmission devices as long as the order wire is not occupied.

[0012]

However, in such a conventional transmission device, when the voice signal sent to the ring network 42 (order wire) does not respond to any of the adjacent transmission devices 41 _{2 to} 42 _4. , The speaker 45 is returned to the transmitter 41 ₁ again under the relay processing performed by these transmitters.
Emitted as sound waves from ₁ . Therefore, howling has occurred in a state where the speaker and the microphone 44 ₁ are acoustically coupled (for example, the microphone 44 ₁ is located at the closest point of the speaker 45 ₁ ).

Further, as a method of preventing such howling, conventionally, a push-type switch used for manual switching between a transmitting state and a receiving state is provided, and a contact of the switch corresponding to the transmitting state is provided. There has been a method of restricting the driving of the handset and the speaker according to the state. However, such a method significantly reduces the efficiency of the meeting as compared with the duplex method, which is applied to a normal telephone as a simplex communication method, and cannot be applied in many cases.

It is an object of the present invention to provide a meeting apparatus capable of avoiding the occurrence of howling while maintaining the communication mode by the duplex system.

[0015]

FIG. 1 is a block diagram showing the principle of the present invention. The present invention is connected to a ring-shaped transmission line through which information indicating the contents of the meeting and control information indicating the transmission source of the information are multiplexed, and the information is obtained by performing separation processing suitable for the transmission method of the ring-shaped transmission line. Means for separating the control information and the control information, a reception means 12 for electro-acoustic conversion of the information separated by the separation means 11 and transmitting a voice indicating the content, and a voice generated by the meeting for acoustic-electricity. Transmitting means 13 for converting and generating voice information,
An information selection means 14 for externally giving an instruction of a timing for transmitting a voice, and selecting either the information separated by the separation means 11 or the voice information generated by the transmission means according to the instruction, and an instruction. Is given from the outside, and the control information selecting means 15 for selecting the control information separated by the separating means 11 or predetermined control information different from the control information according to the instruction, and the information selecting means 1
Multiplexing means 1 for multiplexing the information or voice information selected by 4 and the control information selected by the control information selecting means 15 based on the transmission system and sending out to the transmission path.
6 is compared with the control information separated by the separating means 11 and the control information selected by the control information selecting means 15, and the acoustic coupling between the receiving means 12 and the transmitting means 13 is performed according to the result. Control means 1 for switching and setting the toughness
7 is provided.

[0016]

A plurality of meeting devices according to the present invention are arranged in series on an annular transmission line. In these meeting devices, in a standby state where no meeting is carried out, the control information selecting means 15 selects the control information separated by the separating means 11 according to an instruction indicating the state and gives it to the multiplexing means 16. The information selecting means 14 selects the information separated by the separating means 11 and supplies it to the multiplexing means 16. Therefore, the relay processing for the ring-shaped transmission path is sequentially performed, and the control means 17 transmits to the receiving means 12 because the control information selected by the control information selecting means 15 is equal to the control information separated by the separating means 11. Means 1
Coarsely set the acoustic coupling between 3 and.

Among the waiting meeting devices thus arranged, one of the meeting devices (hereinafter referred to as "callee device") connected via the ring-shaped transmission line should be called up (hereinafter, "calling device"). In the "device"), the information selecting means 14 selects the voice information generated by the transmitting means 13 according to an instruction given from the outside, and the control information selecting means 15 determines the predetermined control information according to the instruction. Select. The multiplexing means 16 multiplexes the voice information selected in this way and the predetermined control information and sends them to the ring transmission line.

In the called device, the separating means 11 takes in the voice information and the predetermined control information multiplexed in this way from the ring transmission line and separates them. The control means 17 differs between the control information separated in this way and the control information selected by the control information selection means 15 in the course of the preceding relay processing, and therefore, between the reception means 12 and the transmission means 13. The acoustic coupling of is set to nectar. Therefore, the voice information separated by the separating means 11 is electro-acoustic converted by the receiving means 12, and the voice information sent from the calling device to the ring transmission line can be heard as sound. Further, when an instruction requesting to answer the ringing with such a sound is given from the outside, the information selecting means 14 selects the voice information generated by the transmitting means 13, and the control information selecting means 15 described above. The control information different from the predetermined control information is selected. The multiplexing means 16 multiplexes the voice information and the control information selected in this way and sends them to the ring transmission line.

In the calling device, the separating means 11 takes in and separates the voice information and the control information thus multiplexed from the ring transmission line. The control means 17 precedes the control information separated in this way by the control information selection means 1
Since the predetermined control information selected by 5 is different, the acoustic coupling between the receiving means 12 and the transmitting means 13 is set to a narrow value. In such a state, the voice information separated by the separating unit 11 is electro-acoustic converted by the receiving unit 12, and the voice information transmitted from the called device to the ring transmission line becomes audible as a sound and is transmitted. Transmission is continued through the means 13, the information selecting means 14 and the multiplexing means 16.

Therefore, a communication path by a duplex system is formed between the calling device and the called device by a ring transmission path, and a meeting is held through the communication path. Also,
The period from when the above-mentioned instruction is given in the calling device until the called device responds and different control information is received, and after the calling device restarts the relay process in response to the end of the call, In the period from the time when the control information received through the relay processing in the calling device matches the predetermined control information sent earlier to the time when the instruction is withdrawn, the control means 17 controls the control information to be compared. Therefore, the acoustic coupling between the receiving means 12 and the transmitting means 13 is roughly set. Therefore, as compared with the conventional example in which the acoustic coupling between the receiving means 12 and the transmitting means 13 is continuously set to be narrow, the possibility of howling is significantly suppressed.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is a diagram showing an embodiment of the present invention.

In the figure, parts having the same functions and configurations as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted here. The characteristic configuration of the present embodiment is the configuration of the transmission devices 21 _{1 to} 21 ₄ provided in place of the transmission devices 41 _{1 to} 41 ₄ in the present embodiment.

Transmission device 21₁Then, the exit route of the ring net 42
Is the separation unit 22₁Is connected to the input of the
Duplication section 23₁Connected to the first input of. Separation part 22₁
The second output of the control unit 24₁Connected to one input of
The first output is the multiplexer 23.₁Connected to the second input of
Be done. Microphone 44₁Is the amplifier 25₁Via codec
26₁Connected to the encoded input of the
Processing unit 27₁Via the multiplexing unit 23₁To the third input of
Will be continued. Separation part 22₁The third output of is the codec 26
₁Is connected to the decoding input of the
8₁Through the speaker 45₁Connected to. Control unit 24
₁The other input and amplifier 25₁The control input of
J 29₁Grounded via the control unit 24₁Second output of
Is the ID processing unit 27₁Connected to the control input of. Control unit 2
Four₁The third output of the amplifier 28 ₁Connected to the control input of
Be done.

Since the configurations of the transmission devices 21 _{2 to} 21 ₄ are the same as the configurations of the transmission device 21 ₁ , respectively, subscripts " ₂ " to " ₄ " are assigned to the respective corresponding components.
The same reference numerals are assigned to the symbols, and their illustration and description are omitted here.

Regarding the correspondence between this embodiment and the block diagram shown in FIG. 1, the separating unit 22 corresponds to the separating means 11, the codec 26, the amplifier 28 and the speaker 45.
Corresponds to the receiving means 12, the microphone 44, the amplifier 25 and the codec 26 correspond to the transmitting means 13, and the control unit 2
4, the ID processing unit 27 and the multiplexing unit 23 correspond to the information selecting unit 14 and the control information selecting unit 15, and the multiplexing unit 2
3 corresponds to the multiplexing means 16, and the control unit 24 and the amplifier 28 correspond to the control means 17.

FIG. 3 is an operation timing chart of this embodiment. The operation of this embodiment will be described below with reference to FIGS. In the transmission devices 21 _{1 to} 21 ₄ , the demultiplexing units 22 _{1 to} 22 ₄ and the multiplexing units 23 ₁ to 23 ₄ are connected to the ring network 42 for a predetermined number of lines and order wires based on the traffic distribution. subjected to separation (demultiplexing) process and the multiplexing process at point, and performs the call processing for transit calls 42 (. including orderwire) telephone terminal 43 ₁ to 43 calls and cyclic network according to _4. Since these processes are performed in the same manner as the conventional example, the description thereof will be omitted here.

Further, in the transmission devices 21 _{1 to} 21 ₄ , the demultiplexing units 22 _{1 to} 22 ₄ respectively take in the multiplexed signals received from the adjacent transmission devices via the ring network 42 and perform the above demultiplexing processing. , The transmission information related to the order wire is extracted from the channels multiplexed in the multiplexed signal. In a state where no transmission is performed to such an order wire, the contacts of the switches 29 _{1 to} 29 ₄ are set to the open state, and the control units 24 _{1 to} 24 ₄ are set to the state of such contacts. Depending on the amplifier 28 ₁ ~
28 ₄ is set to the operating state. Codec 26 _1-26
4 takes in the transmission information extracted by the separation unit 22 ₁ to 22 ₄ as described above is converted into an analog audio signal, the speaker 45 ₁ via the amplifier 28 ₁ to 28 ₄
Give to 45 _4.

Further, in such a state, the multiplexing unit 2
3 ₁ to 23 ₄ send the transmission information extracted by the separating units 22 _{1 to} 22 ₄ as the transmission information of the order wire to the adjacent transmission device via the ring network 42 as described above.

Therefore, in the transmission devices 21 _{1 to} 21 ₄ , the audio signals transmitted and received between the transmission devices via the order wires are constantly intercepted as the voices emitted from the speakers 45 _{1 to} 45 ₄ , and the transmission information related to the order wires. Is relayed to the adjacent transmission device via the ring network 42 (FIG. 3 (1)). In the following, such a series of processes will be simply referred to as “relay process”. Further, 2-bit identification information (hereinafter simply referred to as "ID". Here, an initial value is given as a logical value "00") is superimposed on the transmission information related to the order wire. I shall.

In the transmission device 21 ₁ , when a call is transmitted to a specific transmission device (hereindicated by reference numeral “21 ₃ ” for simplicity) via the order wire, the switch 29 ₁ is operated. The contact is closed according to the operation of the operator
(Fig. 3 (2)). The amplifier 25 ₁ is brought into an operating state according to the state of such a contact, and amplifies the voice signal sent from the microphone 44 ₁ to a predetermined level. The codec 26 ₁ encodes the audio signal thus amplified.

On the other hand, when the control section 24 ₁ recognizes that the contact of the switch 29 ₁ is closed, it stops the operation of the amplifier 28 ₁ and issues a transmission request to the ID processing section 27 ₁ . The ID processing unit 27 ₁ sets the logical value of the above-mentioned ID to “01” and outputs it in response to the transmission request. The multiplexing unit 23 ₁ multiplexes such an ID with the voice signal encoded by the codec 26 ₁ as described above to generate transmission information and sends it to the ring network 42.

In the transmission devices 21 _{2 to} 21 ₄ , the above-mentioned relay processing is continued and the speaker 45 ₂ sends out a voice call message (FIG. 3 (3)). In the transmission device 21 ₃ , when the contact person of the switch 29 ₃ is closed by the maintenance person who listens to such a message, the amplifier 25 ₃ is put into operation according to the state of the contact point (FIG. 3 (4)). The codec 26 ₃ encodes the audio signal supplied from the microphone 44 ₃ via the amplifier 25 ₂ . Further, the control unit 24 ₃ emits a response request to the ID processing unit 27 _3, ID processing unit 27 ₃ in response to the response request I
The logical value of D is set to "10" and output. Multiplexer 2
3 ₃ multiplexes such an ID into the voice signal encoded by the codec 26 ₃ as described above to generate transmission information and sends it to the ring network 42.

In the transmission device 21 ₁ , the control unit 24 ₁ takes in such transmission information from the ring network 42 via the separation unit 22 ₁ under the relay processing performed by the transmission device 21 ₄ , and superimposes it on the transmission information. When it is recognized that the logical value of the generated ID is "10" indicating the response of the transmission device 21 ₃ , the amplifier 28 ₁
Is set to the operating state again (Fig. 3 (6)).

[0034] That is, during the transmission device 21 _1, 21 _3, a microphone 44 _1, amplifier 25 _1, codec 26 _1,
ID processing unit 27 ₁ , multiplexing unit 23 ₁ , ring network 42, transmission device 21 ₂ (detailed signal flow is omitted here), ring network 42, separation unit 22 ₃ , codec 26 ₃
And a downstream transmission path reaching the speaker 45 ₃ via the amplifier 28 ₃ , a microphone 44 ₃ , an amplifier 25 ₃ , a codec 26 ₃ , an ID processing unit 27 ₃ , a multiplexing unit 23 ₃ , and a ring network 4.
2, transmission device 21 ₄ (detailed signal flow is omitted here), ring network 42, separation unit 22 ₁ , codec 26
_A full-duplex communication path including an upstream transmission path reaching the speaker 45 ₁ via the amplifier ₁ and the amplifier 28 ₁ is formed (FIGS. 3 (6) and (7)).

Therefore, a verbal meeting is performed between the transmission devices 21 ₁ and 21 ₃ via the order wire. Further, in the transmission device 21 ₁ , when the operator who has judged that such a meeting is finished opens the contact of the switch 29 ₁ (FIG. 3 (8)), the control unit 24 ₁ is given to the ID processing unit 27 _1. The transmission request that has been released is released, and the relay processing via the demultiplexing unit 22 ₁ and the multiplexing unit 23 ₁ is restarted. Therefore, from the transmission device 21 ₃ to the transmission device 21 ₄ and the ring network 4
The transmission information (including the ID (= “10”) received via 2 is transmitted via the ring network 42 to the adjacent transmission device 21.
₂ is transmitted (Fig. 3 (9)).

In the transmission device 21 ₃ , the separation unit 22 ₃ extracts such transmission information received via the transmission device 21 ₂ and the ring network 42, and the control unit 24 ₃ transmits the thus extracted transmission information. The logical value of the ID included in the information is "10"
When the logic value is recognized, the operation of the amplifier 28 ₃ is continuously stopped while the logic value is continuously detected (see FIG. 3).
(Ten)) .

Further, when the operator who intends to end the above-mentioned meeting sets the contact of the switch 29 _{3 in} an open state (FIG. 3 (11)), the control unit 24 ₃ causes the ID processing unit 27 to operate.
_A recovery request is given to ₃ over a predetermined time t.
ID processing unit 27 ₃ performs the processing for securing sets the logical value of the ID in the course of the relay processing according to orderwire transmission information in response to such a recovery request to "00". here,
The time t is set to a value obtained by adding a predetermined margin to the time taken for the transmission information to go around the ring network 42 under the relay processing performed by the transmission devices 21 ₄ , 21 ₁ and 21 ₂ . Therefore, the logical value of the ID superimposed on the transmission information is restored to "00", which is the same as before the start of the meeting via the order wire in any section of the ring network 42 (FIG. 3 (12)). Control unit 2
4 _3, when such a time t has elapsed, by releasing the recovery request described above to start the normal relay process (FIG. 3 (13))
.

As described above, according to the present embodiment, in the transmission devices for conducting the meeting opposite to each other via the order wire, the contacts of the switches provided in these transmission devices are closed except during standby. Since the speaker is driven only in the state, the possibility of howling is significantly reduced as compared with the conventional example in which the speaker is continuously driven.

In the present embodiment, in the transmission device which has not been discussed, the audio information decoded in the process of relaying the order wire can be continuously heard through the speaker 45. Is not limited to such a configuration, and when a selective calling method capable of surely calling a transmission device to be a meeting partner is applied, the contact of the switch 29 is opened and the speaker 45 of the speaker 45 is opened. The driving may be stopped.

In the present embodiment, howling is avoided by stopping the operation of the amplifier 28 under the control of the control section 24, but the present invention is not limited to such a configuration. , For example, the codec 26 and the amplifier 2
5 may be stopped, or a signal applied to the decoding input of the codec may be masked. By reducing the amplification factor of the amplifier 28 or the amplifier 25, the speaker 45 and the speaker 45 may be controlled to the extent that howling does not occur. The acoustic coupling with the microphone 44 may be roughly set.

Further, in this embodiment, the transmission devices 21 ₁ ...
The communication path of the order wire is secured under the relay processing performed by the transmission devices 21 ₂ and 21 ₄ arranged between 21 ₃ but the present invention is not limited to such a configuration. For example, the transmission device 21 _{The same} can be applied to the case where there is no transmission device between _{1 and} 21 ₃ .

Further, in the present embodiment, the starting point of the timing of transmitting, receiving, updating the ID to be transmitted, and other timing is given according to the state of the contact of the switch 29 operated by the operator. Not limited to such a switch,
For example, a switch that switches on and off in response to an operator's voice may be used, or a switch that switches on and off automatically in response to the supply of a message to be notified to each transmission device may be used.

Further, in the present embodiment, the ID is composed of three kinds of bit strings, "00" indicating a no-call state, "01" indicating a calling state, and "10" indicating a response state. Is not limited to the number of bits of the ID, the bit pattern, and the allocation of the bit pattern. For example, the identification information indicating the transmission device (meeting device) is used as the ID indicating the calling state or the response state, and there is no call. A bit pattern that can be distinguished from such identification information may be used as the ID indicating the state.

[0044] In this embodiment, the present invention is applied to a transmission device 41 ₁ to 41 ₄ disposed over and adjacent to the annular grid 42, the order wire is configured as a multiplexed line to the annular network However, the present invention is not limited to such a configuration, and is similarly applicable to, for example, a meeting device adjacently arranged on an annular net that constitutes only such an order wire.

Further, in the present embodiment, the voice signal encoded by the codec 26 and the 2-bit ID are time-division multiplexed and sent to the ring network 42, but the present invention is such a time division. The ring network 4 is not limited to the multiplexing system.
If it conforms to the second transmission method, for example, even if a multiplexing method such as a frequency multiplexing method or a CDMA (SSMA) method is applied, or a logical multiplexing method using packets or cells is applied. Good.

Further, in the present embodiment, the ring network 42 is constructed as a wired transmission line, but the present invention is not limited to such a transmission line, and is provided for each section sandwiched by transmission devices (meeting devices). If the relay transmission path is formed surely, the wireless transmission path or the optical transmission path may intervene in all or part of these sections. Further, in each section, any analog transmission method or digital transmission method may be used, and any transmission procedure may be applied, as long as it conforms to such a transmission path format.

[0047]

As described above, according to the present invention, the calling, the response, and the end of the call between the calling device and the called device are performed based on the relay transmission performed via the ring transmission line. Control information to be identified is transmitted and received together with voice information, and based on these control information, the state in which both parties can transmit and receive in parallel is detected, and thus the acoustic coupling between the receiving means and the transmitting means is closely connected. Set.

That is, since the howling that occurs in the conventional example is avoided while ensuring the call form by the duplex system, the call quality of the meeting is improved and the operation is performed in the transmission section to which the present invention is applied. The efficiency and environment of the work involved is enhanced.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a diagram showing an embodiment of the present invention.

FIG. 3 is a timing chart of the present embodiment.

FIG. 4 is a diagram showing a configuration example of a conventional ring network.

[Explanation of symbols]

 11 Separating Means 12 Receiving Means 13 Transmitting Means 14 Information Selecting Means 15 Control Information Selecting Means 16 Multiplexing Means 17 Control Means 21, 41 Transmission Equipment 22 Separating Means 23 Multiplexing Means 24 Controlling Means 25, 28 Amplifiers 26 Codecs 27 ID Processing Part 42 Ring network 43 Telephone 44 Microphone 45 Speaker

Claims (1)

[Claims] 1. A ring-shaped transmission line on which information indicating the contents of the meeting and control information indicating the transmission source of the information are multiplexed and connected, and a separation process suitable for the transmission system of the ring-shaped transmission line is performed to perform the separation processing. Separation means for separating information and control information
(11) and the reception means (1) for electro-acoustic conversion of the information separated by the separation means (11) and transmitting a voice indicating the content.
2), a transmitting means (13) for acousto-electrically converting a voice emitted in association with the meeting to generate voice information, and an instruction of a timing for transmitting the voice is given from the outside, and the instruction is given to the instruction. In response to the information selection means (14) for selecting either the information separated by the separation means (11) or the voice information generated by the transmission means, the instruction is given from the outside and Control information selecting means (15) for selecting control information separated by the separating means (11) or predetermined control information different from the control information, and information or voice information selected by the information selecting means (14) And a multiplexing means (16) for multiplexing the control information selected by the control information selecting means (15) based on the transmission method and sending the multiplexed information to the transmission path, and the separating means (1). ) And the control information selected by the control information selecting means (15) are compared, and the control information between the receiving means (12) and the transmitting means (13) is compared according to the result. A meeting device comprising a control means (17) for switching and setting acoustic coupling to coarseness.