Control method for isdn audio visual terminal equipment

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a method of controlling a plurality of ISDN audiovisual terminal devices connected to a passive bus of the same ISDN basic interface.

【0002】

[Conventional technology]

The narrowband videophone / teleconferencing system and its terminal equipment (audiovisual terminal equipment) specified in CCITT (International Services Digital Network) Recommendation H.320 and TTC Recommendation JT-H.320 are audio, video, and so on. Multimedia communication that handles multiple media such as documents and images can be realized using ISDN.

【0003】

In addition, CCITT regarding a multi-point control unit (MCU) for connecting audio-visual terminal devices currently installed at multiple points and enabling video conferencing that integrates them. The standardization work of Recommendation AV.231 in is being carried out.

【0004】

FIG. 46 shows an example of a video conferencing system when this multipoint connection device is used.

【0005】

In the figure, the video conferencing devices 1a, 1b, 1c are connected to the network control terminal devices 3a, 3b, 3c of ISDN2, and in this case, the video conferencing devices 1b, 1c are provided in the same house. ing. Further, the multipoint connection device 4 is connected to ISDN2 via a plurality of network control terminal devices 5 (1) to 5 (n).

【0006】

Each of the video conferencing devices 1a, 1b, and 1c sets a call for the multipoint connection device 4, and establishes an information channel with the multipoint connection device 4. Then, the multipoint connection device 4 transfers data such as audio, video, document, and image between the connected video conferencing devices 1a, 1b, 1c from each of the video conferencing devices 1a, 1b, 1c. Exchange as appropriate according to the request of.

【0007】

For example, the multipoint connection device 4 divides the display screen of the video data output to the video conferencing device 1a into two, and the video output from the video conferencing device 1b and the video conferencing device 1c is displayed on each divided screen. As described above, the video data output from the video conferencing devices 1b and 1c are combined, the audio data output from the video conferencing devices 1b and 1c is combined into one audio data, and the combined audio data is combined with the video conferencing device. It also provides a function to output to 1a.

【0008】

Further, as shown in FIG. 47, the multipoint connection device 4 can be incorporated into the premises exchange device 7 connected to the ISDN2 via a plurality of network control terminal devices 6a and 6b. In this case, the video conferencing devices 1b and 1c are connected to the extension side of the premises switching device 7 via the network termination devices 8a and 8b.

【0009】

In this case, the video conferencing communication between the video conferencing devices 1a, 1b and 1c becomes possible, and the video conferencing communication between the video conferencing devices 1b and 1c connected to the premises exchange device 7 is possible. Becomes possible.

【0010】

[Problems to be Solved by the Invention]

However, the video conferencing system using such a multipoint connection device has the following inconveniences.

【0011】

That is, in the above-mentioned video conferencing system, one ISDN line is required for each video conferencing device, and a multipoint connection device is required, which causes a disadvantage that the system cost becomes very large.

【0012】

Also, considering the progress of the meeting, if all the people participating in the meeting speak at the same time, the meeting will be confused and the proceedings will be delayed. The proceedings proceed.

【0013】

On the other hand, since it is natural that such proceedings are also applied to the video conferencing system, there is no situation in which all the terminal devices make statements at the same time during the conferencing, and therefore, the entire system. The total amount of data per unit time of the transmission data exchanged in is expected to be considerably smaller than the data transmission capacity per unit time of the transmission data possible in the entire system, the utilization efficiency of the ISDN line becomes poor, and the line cost There is a risk that the data will be unnecessarily high.

【0014】

Further, for example, as shown in FIG. 48, consider a case where one video conferencing device 10 and a plurality of seats 11a, 11b, 11c, 11d, 11e, 11f face each other across one conference table 9. .. Further, in this case, the projector 12 is provided behind the video conferencing device 10, and the display content of the display device provided in the main body of the video conferencing device 10 can be enlarged and projected. Further, the video conferencing device 10 is connected to ISDN via the network control terminal device 13.

【0015】

Now, in this case, when a person seated in each of the seats 11a, 11b, 11c, 11d, 11e, 11f speaks, the video camera (not shown) of the video conferencing device 10 is pointed at the speaker. There is a need.

【0016】

On the other hand, as the proceedings progress, people seated in seats 11a and 11f at the ends may speak alternately. In this case, the camera angle of the video camera swings continuously from seat 11a to seat 11f. Will be.

【0017】

In this way, when changing the camera angle of a video camera, if the image in the state of being changed is displayed on the video conferencing device on the other side, the person watching the screen feels uncomfortable, so-called camera sickness. Things can happen.

【0018】

In order to prevent such camera sickness, a video camera that captures each seat 11a, 11b, 11c, 11d, 11e, 11f is provided, and the effective video camera is switched each time the speaker changes, or each seat is used. It is conceivable to install a video conferencing device in each.

【0019】

However, in the former case, it is necessary to construct the video conferencing device 10 according to the number of participants, and as a result of losing the versatility of the video conferencing device 10, the device cost of each video conferencing device 10 is lost. In the latter case, the equipment cost and the line cost of the video conferencing system become enormous.

【0020】

Further, when presenting a still image such as characters, figures and photographs to the other party, the participant needs to keep looking at the still image display device (for example, the projector 12) provided in the video conferencing device, and the participant needs to keep an eye on the still image display device (for example, the projector 12). On the other hand, there may be an inconvenience of forcing an unnatural posture, which causes an unfavorable situation on the man-machine interface.

【0021】

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a control method for an ISDN audiovisual terminal device capable of realizing a video conferencing system at low cost.

【0022】

[Means for solving problems]

The present invention comprises a transmission signal synchronization means for synchronizing transmission signals of each ISDN audiovisual terminal device in a control method of a plurality of ISDN audiovisual terminal devices connected to a passive bus of the same ISDN basic interface. It is equipped with a transmission signal selection means that selectively effectively outputs the transmission signal of the ISDN audiovisual terminal device to the passive bus, and a specific ISDN audiovisual terminal device performs call setting / release procedures with and from the ISDN, and each ISDN. The audiovisual terminal device receives the received signal via the passive bus and outputs the received information, while effectively outputting the transmitted signal by the transmission signal selection means based on the transmission request of each ISDN audiovisual terminal device. The ISDN audiovisual terminal device is selected.

【0023】

In the control method of multiple ISDN audiovisual terminal devices connected to the passive bus of the same ISDN basic interface, the transmission signal synchronization means for synchronizing the transmission signals of each ISDN audiovisual terminal device and each ISDN audiovisual terminal device. Each ISDN audiovisual terminal device is equipped with a communication means for connecting and exchanging control information, and a specific ISDN audiovisual terminal device performs a call setting / release procedure with ISDN, and each ISDN audiovisual terminal device is via a passive bus. While receiving a received signal and outputting the received information, a specific ISDN audiovisual terminal device is controlled to specify an ISDN audio terminal device that effectively outputs a transmitted signal based on a transmission request of each ISDN audiovisual terminal device. The signal is notified to each ISDN audiovisual terminal device via a communication means, and the designated audiovisual terminal device effectively outputs the transmission signal.

【0024】

Select one of the layer 1 signal control means that separates and integrates the received signal and the transmitted signal on the ISDN basic interface and the transmitted signal output from multiple ISDN audiovisual terminal devices and outputs them to the layer 1 signal control means. Each ISDN audiovisual terminal device is provided with a transmission signal selection means for synchronizing the transmission signal of each ISDN audiovisual terminal device, and a specific ISDN audiovisual terminal device performs a call setting / release procedure with ISDN, and each is performed. ISDN audio visual terminal device receives the received signal output from the layer 1 signal control means and outputs the received information, while the transmission signal selection means is used based on the transmission request of each ISDN audio visual terminal device. The ISDN audiovisual terminal device that effectively outputs the transmission signal is selected.

【0025】

Further, the transmission signal synchronization means performs frame synchronization included in the frame data of the transmission signal at a timing when a predetermined delay time elapses from the timing of detecting the frame synchronization signal included in the frame data constituting the data transfer unit of the reception signal. The signal output timing is set.

【0026】

Further, the transmission signal synchronization means is a delay time detection means that detects a delay time based on the difference between the frame synchronization signal detection timing of the received signal and the output timing of the frame synchronization signal of the transmission signal in a specific ISDN audiovisual terminal device. The delay time from the frame synchronization signal detection timing of the received signal to the output timing of the frame synchronization signal of the transmission signal in the ISDN audio visual terminal device other than the specific ISDN audio visual terminal device corresponds to the detection value of the delay time detection means. It is provided with a delay time setting means for setting the time.

【0027】

Further, the transmission signal synchronization means outputs a synchronization signal to each ISDN audiovisual terminal device at a time interval corresponding to the frame repetition cycle of the transmission signal.

【0028】

Further, the transmission signal synchronization means is such that the frame synchronization timing of the transmission signal output from the specific ISDN terminal device is matched with the frame synchronization timing of the transmission signal of the ISDN terminal device other than the specific ISDN terminal device. Is.

【0029】

[Action]

Therefore, since a video conferencing system can be constructed using a plurality of ISDN audiovisual terminal devices connected to the same ISDN basic interface, the line cost of the entire video conferencing system can be reduced. Also, since each participant can occupy and use one ISDN audiovisual terminal device, unfavorable situations that occur in the proceedings, such as camera sickness caused by frequent switching of camera angles, etc. Since it is possible to eliminate the unnatural posture for viewing a still image, the usability of the video conferencing system is improved and the effectiveness of the video conferencing system is improved.

【0030】

[Example]

Hereinafter, examples of the present invention will be described in detail with reference to the accompanying drawings.

【0031】

FIG. 1 illustrates one home station of a video conferencing system according to an embodiment of the present invention.

【0032】

In the figure, the network control terminal device 20 connected to ISDN is connected to the passive bus 21 of the ISDN basic interface, and the passive bus 21 is connected to six audiovisual (hereinafter abbreviated as AV) terminal devices. 22,23,24,25,26,27 are connected. The terminator 28 is for terminating the passive bus 21.

【0033】

These AV terminal devices 22, 23, 24, 25, 26, 27 are equipped with the terminal functions of the narrowband videophone / conference system of TTC Recommendation JT-H.320, and each has a common conference table 29. It is placed on top. In addition, six seats 30,31,32,33,34,35 are arranged toward the conference table 29 at positions corresponding to the AV terminal devices 22,23,24,25,26,27, respectively. There is.

【0034】

Since the AV terminal devices 22,23,24,25,26,27 are lightweight and compact, the participants of the conference seated in the seats 30,31,32,33,34,35 are each AV terminal device 22,23,23, You can adjust the orientation of the 24, 25, 26, 27 screens and video cameras (not shown) to suit your needs.

【0035】

These AV terminal devices 22, 23, 24, 25, 26, 27 are terminal devices that use ISDN as a transmission line, and FIG. 2 (a) shows that the terminal devices connected to ISDN are ISDN. An example of the call control procedure in the circuit-switched mode performed between the two is shown.

【0036】

That is, the outgoing terminal first sets the circuit-switched mode as the transfer mode, and also sends a call setting message SETUP with the incoming terminal as the destination to the ISDN to request the call setting with the incoming terminal, and the ISDN specifies. A call setting message SETUP is sent to the incoming terminal to make a call. In addition, ISDN sends a call setting acceptance message CALL_PROC to the calling terminal to notify the call setting status.

【0037】

When the incoming terminal detects an incoming call, it sends a call message ALERT to ISDN when the local terminal is ready to receive an incoming call, and ISDN sends a call message ALERT to the outgoing terminal to start calling the incoming terminal. Notify.

【0038】

When the incoming terminal answers an incoming call, the incoming terminal sends a response message CONN to ISDN, and the ISDN sends a response message CONN to the outgoing terminal to notify that the incoming terminal has accepted the call.

【0039】

In addition, ISDN sends a response confirmation message CONN_ACK to the incoming terminal to confirm the response of the incoming terminal, and at that point, an information channel (B channel) for data transmission is established between the outgoing terminal and the incoming terminal. ..

【0040】

As a result, data transmission using the information channel between the outgoing terminal and the incoming terminal is executed by the transmission control procedure set in the transmission function of each terminal.

【0041】

Then, when the data transmission is completed, the originating terminal sends a disconnection message DISC to ISDN to request the release of the information channel, and ISDN sends a release message REL to the originating terminal to notify the restoration of the information channel. On the other hand, the ISDN sends a disconnection message DISC to the incoming terminal to request the release of the information channel, and the incoming terminal sends a release message REL to the ISDN to notify the restoration of the information channel.

【0042】

As a result, the outgoing terminal responds to the ISDN with a release completion message REL_COMP notifying the completion of channel disconnection, and the information channel between the outgoing terminal and the ISDN is released. At the same time, ISDN sends a release completion message REL_COMP to the incoming terminal, and the information channel between ISDN and the incoming terminal is released. As a result, the information channel set between the outgoing terminal and the incoming terminal is completely released.

【0043】

In this way, an information channel is set between the outgoing terminal and the incoming terminal, data transmission is performed, and when the data transmission is completed, the information channel is released.

【0044】

In addition, as shown in Fig. 3 (a), each message for ISDN call setting includes a protocol identifier for identifying the protocol specification (format, sequence, etc.) that defines the layer 3 call control message, and the message. A call number to identify which call is involved, a message type to identify the content of each message, required information elements that are always attached to each message, and required for each message. It consists of additional information elements added accordingly. Note that 0,1, or a plurality of essential information elements are set according to the message type, and 0,1, or a plurality of additional information elements are arranged according to the situation.

【0045】

As shown in Fig. (B), the call setting message SETUP has "transmission ability" as an essential information element, and examples of additional information elements include "calling number", "arrival number", and "arrival subaddress". It has information elements such as "low layer integrity", "high layer integrity", and "user-user".

【0046】

The outline of these information elements will be described.

【0047】

The "transmission capability" information element is an information transfer capability that indicates whether the content of the information to be transmitted is voice, unrestricted digital information, restricted digital information, 3.1KHz audio, 7KHz audio, or video. It consists of a transfer mode that indicates whether the exchange function is line exchange or packet exchange, an information transfer speed that indicates the speed of information transfer, information that indicates the form of information transfer, and information that indicates the protocol of user information.

【0048】

The "calling number" information element represents the ISDN number of the calling terminal, and the "arrival number" information element represents the ISDN number of the calling terminal. The "arrival subaddress" information element is for identifying the target one of up to eight terminals connected to the same home wiring (passive bus) on the arrival side.

【0049】

The "low layer consistency" information element is for use in the communicability test with the other terminal, and the basic content is the same as the "transmission ability" information element. In addition, this "lower layer integrity" information element contains more detailed content (eg, CCITT Recommendation H.221 feature).

【0050】

The "higher layer integrity" information element is intended to be used for consistency checking with the other terminal, for example, Group 2 / Group 3 Facsimile, Group 4 Facsimile, Mixed Mode, Teletex, Videotex, Telex, Alternatively, the message handling system or the terminal function such as AV, which terminal function is provided is displayed.

【0051】

The "user-user" information element is intended to be used to convey information between users, and the content of this "user-user" information element is transparently transferred to the other user without being interpreted by ISDN. Be transmitted.

【0052】

By the way, in the AV terminal device, data is exchanged in the multi-frame format specified in TTC Recommendation JT-H.221 on the B channel.

【0053】

As shown in FIG. 4, one multi-frame MFL is composed of eight sub-multi-frames SMF1 to SMF8, and each sub-multi-frame SMF1 to SMF8 is composed of two frames. That is, one multi-frame MFL consists of 16 frames FLM0 to FLM15.

【0054】

As shown in FIG. 5, each frame FLM0 to FLM15 consists of 80 octets of data, and each bit position in which those octets are arranged in bit order constitutes subchannels SCH1 to SCH8.

【0055】

In addition, the 8th bit of the 1st octet to the 8th octet constitutes the Frame Alignment Signal FAS, and the 8th bit of the 9th octet to the 16th octet constitutes the Bit rate Allocation Signal. ) Configure BAS. That is, the sub-channel SCH8 is assigned to the 8th bit of the 17th octet to the 80th octet, and this part is sometimes called the application channel AC (Application Channel). In addition, the data of the encryption channel for exchanging key information for encrypting the data may be set in the 17th to 24th octets of the subchannel SCH8 (optional).

【0056】

In this way, the frame synchronization signal FAS is arranged in 8 bits in one frame FLM1 to FLM16, and the bit allocation is configured in units of multi-frame MFL as shown in FIG.

【0057】

That is, the second to eighth octets of the even frames FLM0, FLM2, ..., FLM14, and the subsequent odd frames FLM1, FLM3, ..., FLM15 consist of an 8-bit data pattern of "00110111". A horizontal synchronization signal is arranged, and a vertical synchronization signal consisting of a 6-bit data pattern of "001011" is arranged in the first octet of odd-numbered frames FLM1, FLM3, ..., FLM11.

【0058】

By detecting the horizontal synchronization signal and the vertical synchronization signal, it is possible to detect the synchronization of one multi-frame MFL.

【0059】

The bits N1, N2, N3, N4, N5 of the first octet of the 0th frame, the 2nd frame, the 4th frame, the 6th frame, and the 8th frame are used for displaying the multi-frame number. Of these, bit N5 is used to indicate whether or not a multiframe number is used. In this way, since the data used for the multi-frame number is 4 bits, the multi-frame number changes in descending order with a value from 0 to 15, and the same multi-frame number appears every 16 multi-frames.

【0060】

In addition, the bits L1, L2, and L3 of the first octet of the 10th frame, the 12th frame, and the 13th frame are connected to the information channel carrying the frame among the currently used information channels. It is used to display the connection number that represents the order. Also, the bit R of the first octet of the 15th frame is reserved (reserved) for future recommendations and is set to 0.

【0061】

Further, the bit TEA of the first octet of the 14th frame is used to indicate that data transmission is not possible due to an internal failure of the data terminal device.

【0062】

Bit A in the third octet of odd-numbered frames FLM1, FLM3, ..., FLM15 is used to indicate whether frame synchronization or multi-frame synchronization has been established, or whether synchronization has occurred.

【0063】

Also, the bits C1, C2, C3, C4 of the 5th octet, 6th octet, 7th octet, and 8th octet of the odd frames FLM1, FLM3, ..., FLM15 are two consecutive frames (that is, It is for displaying the CRC (Cyclic Redundancy Check) code referred to for data error detection (that is, transmission line quality detection) of sub-multiframe), and this odd frame FLM1, FLM3, ..., FM15. Bit E in the 4th octet of is used to indicate that a transmission error has been detected on the receiving side.

【0064】

As for the bit rate allocation signal BAS, as shown in FIG. 7, in the even frame FLM0, FLM2, ..., FLM14, 8-bit data representing the capability BAS or BAS command is arranged, followed by the odd frame FLM1, FLM3. , ..., FLM15 is arranged with a double error correction code for error-correcting the value of the capability BAS or BAS command sent in the immediately preceding frame.

【0065】

In addition, the data of the multi-frame MFL is transmitted in the order of the frame numbers, and each frame FLM0 to FLM15 is sent in the octet order of the 1st octet to the 80th octet as shown in FIG. 8, and each octet is transmitted. , The first bit is sent first.

【0066】

That is, in each frame FLM0 to FLM15, the first bit of the first octet is transmitted first, and the eighth bit of the 80th octet is transmitted last.

【0067】

FIG. 9 shows an example of a transmission procedure when exchanging audio data and video data between AV terminal devices using two information channels. This transmission procedure follows TTC Recommendation JT-H.242 and Recommendation JT-H.320.

【0068】

First, the calling terminal calls the destination terminal, performs a call setting procedure on the signal channel, secures one information channel (hereinafter referred to as the first channel) (Phase A), and then switches on the set first channel. Frame synchronization is performed while exchanging frame data with PCM audio data (A rule or μ rule, 64Kbps) set in (frame mode), and when frame synchronization is established, ability BAS data and command BAS data are exchanged with each other (frame mode). Phase B1-1), the transmission mode to be used at that time is determined, and the additional call setting request for securing the second information channel is started (Phase B1-2).

【0069】

Then, the mode with the highest function common to each other is selected from the contents exchanged with each other at that time (Phase B1-3), and the function is operated from the calling terminal to the called terminal in the selected operation mode. Send a BAS command to specify the terminal function, and set the parameters common to the device functions of the calling terminal and the incoming terminal (Phase B2). As a result, in the first channel, for example, data transmission of audio data (16Kbps) and data transmission of moving image data (46.4Kbps) corresponding to the transmission mode selected at that time are performed (Phase C).

【0070】

When the first channel starts data transmission in frame mode, the call setting procedure is performed on the signal channel for the second information channel (hereinafter referred to as the second channel) (phase CA), and when the second channel is established, the second channel is established. Two channels are used to exchange frame data containing only the frame sync signal FAS and the bit-assigned signal BAS to establish frame sync and multi-frame sync (Phase CB1-11), and then between channels 1 and 2. Establish synchronization (Phase CB1-12).

【0071】

When the synchronization of the two information channels is completed, the BAS command is sent from the calling terminal side to set the transmission mode (Phase CB1-2), and the transmission mode is switched to the set contents (Phase CB1-3), which is common. Set the parameters (Phase CB3).

【0072】

In this way, when the initialization of the second channel is completed, after that, the frame data exchanged on the first channel and the frame data exchanged on the second channel are synchronized, and the two information channels are operated. In use, audio data and video data are data-transmitted at transmission rates of 48 Kbps and 76.8 Kbps, respectively.

【0073】

When ending such data transmission, first disconnect from the second channel. At this time, for audio data transmission performed only on the first channel, a procedure for setting a common mode is performed (phase CD1), and the second channel is mode-switched to mode 0F of the frame mode (phase CD1). Phase CD2). At this time, the first channel and the second channel are asynchronous, and in the second channel, the call is held in the transmission state of only the frame synchronization signal FAS and the bit allocation signal BAS, and the call of the signal channel is disconnected. The release procedure is ready to release the call on channel 2.

【0074】

In addition, in the first channel, between phase CD1 and phase CD2, audio data and video data are transmitted at a total transmission speed of 62.4 Kbps in frame mode, and when the operator of one terminal ends the call, the video is transmitted. End the data transmission, switch to mode 0F to use all the transmission capacity of the first channel including the transmission capacity of this video data for voice transmission (Phase D2), and then disconnect the signal channel call. The release procedure is ready to release the call on channel 1.

【0075】

As a result, for the first channel and the second channel, the call disconnection / release procedure is executed on the signal channel (Phase E), and the AV transmission between the two terminals ends.

【0076】

In this way, in the AV terminal, after first securing one information channel (first channel) and establishing the frame mode, the second information channel (second channel) is secured and the frame mode is established. When the frame mode synchronized with the two information channels is established, audio data and video data are exchanged.

【0077】

Further, when the data transmission is terminated, it is necessary to change from the mode in which the transmission line in which both the first channel and the second channel are synchronized is used to the mode in which only the first channel is used. Therefore, first, each coding rule of audio data and video data is set to a method that optimizes the transmission capacity of 62.4 Kbps of the first channel, and the transmission mode is changed to only the first channel. The synchronization state with the first channel is stopped, the mode shifts to mode 0F in which the user data is in the free transmission state, and the call is disconnected / released according to the call disconnection / release procedure of the signal channel. In addition, after changing from two types of media transmission of audio data and video data to mode 0F, which is a transmission mode of only audio data, the first channel disconnects / releases the call according to the call disconnection / release procedure of the signal channel. .. Note that the first channel can be disconnected / released after the mode is directly changed to mode 0F without switching the mode to two types of media transmission, audio data and video data. In addition, the billing information obtained in the call disconnection / release procedure is managed for each channel.

【0078】

As shown in FIG. 10, the AV terminal devices 22,23,24,25,26,27 connected to the passive bus 21 are one master AV (audiovisual) terminal device MSR and other slave AVs. (Audiovisual) Terminal devices SLV1 to SLVm (in this case, m = 5; see Fig. 1). Here, all or part of the master AV terminal device MSR and the slave terminal devices SLV1 to SLVm are referred to as home stations, and the AV terminal device or multipoint connection device that is the communication partner is referred to as the partner station.

【0079】

This master AV terminal device MSR performs a call setting operation for establishing two information channels with the partner station that holds a video conference, frame synchronization of the information channel, and a call disconnection / release operation, and also performs a call disconnection / release operation with the partner station. The slave AV terminal devices SLV1 to SLVm receive the received signal from the passive bus 21 and output the contents to the output device of the own terminal, and the transmission right (described later). When the data is obtained, the input data obtained from the input device of the own terminal is converted into data in a format corresponding to each input device and sent to the passive bus 21.

【0080】

At this time, only one of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm connected to the passive bus 21 can send a transmission signal to the passive bus 21. Then, when the operator operates the input devices (described later) provided on the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm, the right to transmit the transmission signal (hereinafter referred to as the transmission right) will be granted. It can be set on the terminal device.

【0081】

Further, since the transmission signal needs to maintain the frame synchronization state established with the partner station, in this embodiment, the master AV terminal device MSR and the slave AV terminal are as follows. The transmission signals of the devices SLV1 to SLVm can maintain the same frame state.

【0082】

That is, first, all of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm receive the multiframe with the multiframe number "0" of the received signal, and then transmit it when a predetermined delay time elapses. By forming the multi-frame transmission timing of the signal multi-frame number 0, the frame synchronization states of the transmission signals of the terminal devices are matched.

【0083】

Then, when it is detected that the own terminal has acquired the transmission right by the operation of the operator and when it is detected that the own terminal relinquishes the transmission right, the first multi-frame number from the timing when the operation is detected, respectively. At the timing of the transmission signal of "0", the terminal device that detects the acquisition of the transmission right starts the output of the transmission signal, and the terminal device that detects the abandonment of the transmission right ends the output of the transmission signal.

【0084】

As a result, even when the transmission right is exchanged between the two terminal devices, the partner station can receive the frame data of consecutive multi-frame numbers, so that the frame between the home station and the partner station. The synchronization state is maintained, and stable data communication operation can be performed.

【0085】

When the frame synchronization status is the same between two terminal devices connected to the same passive bus and the transmission right is exchanged between the two terminal devices, the frame between the two terminal devices and the other station In order to maintain the synchronization state, it is sufficient that the frame synchronization signal FAS and the bit rate allocation signal BAS are consistent, so the transmission signal may be switched in sub-multiframe units (see FIG. 11).

【0086】

Therefore, as described above, even when the transmission signal is switched at the timing of the multi-frame number "0", the frame synchronization state with the partner station can be maintained.

【0087】

FIG. 12 shows a configuration example of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm (hereinafter collectively referred to as AV terminal devices).

【0088】

In the figure, the transformer 40 AC-connects the signals of the passive bus 21 connected via the socket 41, and the other connection end is connected to the bus interface circuit 42.

【0089】

The bus interface circuit 42 separates the received signal of the passive bus 21 and outputs it to the layer 1/2 control device 43, and sends the transmission signal output from the layer 1/2 control device 43 to the passive bus 21. The layer 1/2 controller 43 controls the signals of layer 1 and layer 2 of the ISDN basic interface, and separates the signals of the two information channels and one signal channel multiplexed in the transmission / reception signals. It has a function to integrate, the signal on the signal channel is exchanged with the D channel layer 3 control unit 44, and the signal on the two information channels is with the multiplexing / separation control device 45. It is being exchanged between.

【0090】

Here, from the layer 1/2 control device 43 to the multiplexing / separation control device 45, the reception signal RD1 of the B1 channel, the reception signal RD2 of the B2 channel, the bit clock CPb representing the bit timing of the reception signals RD1 and RD2, and the bit clock CPb representing the bit timing of the reception signals RD1 and RD2, and , The octet clock CPo indicating the octet timing of the received signals RD1 and RD2 is output, and the multiplexing / separation controller 45 to the layer 1/2 controller 43 of the B1 channel transmission signal TD1 and the B2 channel The transmission signal TD2 is output.

【0091】

The D-channel layer 3 control unit 43 is for exchanging data between the call control unit 46 that performs call control procedure processing with ISDN and the layer 1/2 control device 43 (interface means). ..

【0092】

The multiplexing / separation control device 45 separates the audio data, video data, and two general-purpose data multiplexed on the received signals RD1 and RD2 and outputs them to the audio CODEC47, the video CODEC48, and the external device, respectively. At the same time, the audio CODEC47, the video CODEC48, and the audio data, the video data, and the two general-purpose data input from the external device are incorporated into the frame data of the predetermined format, and the transmission signals TD1 and TD2 of the frame data are layer 1 /. 2 Output to the control device 43. In addition, a synchronization signal SYC is output for the terminal device that processes general-purpose data.

【0093】

The multiplexing / separation control unit 49 inputs the frame synchronization signal FAS and the bit rate allocation signal BAS detected by the multiplexing / separation control device 45, and controls the operation mode of the multiplexing / separation control device 45. Is.

【0094】

The voice CODEC47 converts the voice signal and the voice data into each other according to a predetermined conversion rule, and the connection end on the voice signal side uses the switch 50 to transmit the handset 51 for a call and various tone signals. It is switched and connected to either the tone generator 52 for output or the input terminal on the 4-wire side of the 2 / 4-wire converter 53. A group 3 facsimile machine 54 for transmitting and receiving original images is connected to the input terminal on the 2-wire side of the 2 / 4-wire converter 53.

【0095】

The video CODEC48 converts the video signal and the video data to each other according to a predetermined conversion rule, and the video signal output end is added to the video monitor device 56 via the video output circuit 55, whereby the video signal output terminal is added to the video monitor device 56. , The image corresponding to the received video data is displayed on the video monitor device 56. Further, the video signal output from the video camera device 57 for inputting video is applied to the video signal input end of the video CODEC 48 via the video input circuit 58.

【0096】

The input device 59 is for the operator to operate the AV terminal device, and is a numeric keypad for dial input, a terminal switching key for inputting acquisition / waiver of transmission right, and various other function keys. The operation signal is applied to the system control unit 60. Further, the system control unit 60 controls the operation of the AV terminal device, and the display device 61 displays various control information such as information indicating the terminal state from the AV terminal device to the operator. belongs to.

【0097】

The power supply device 63 forms a DC power supply from a commercial power supply, and the switch 64 selects the DC power supply output from the power supply device 63 when the power is turned on, and is phantom-powered from the station line in the event of a power failure. The purpose is to select a DC power supply that is installed and supply the selected DC power supply to the DC / DC converter 65. The DC / DC converter 65 uses the added DC power supply to supply various DC power required for this AV terminal device. It is for forming a power source.

【0098】

The part surrounded by the alternate long and short dash line in FIG. 12 is a part that can be operated by the DC power supply supplied from the DC / DC converter 65 even during a power failure.

【0099】

Therefore, this AV terminal device can perform a call operation using the handset 51, a still image transmission / reception operation using the group 3 facsimile device 54, and a video information transmission / reception operation using the video monitor device 56 and the video camera device 57. Therefore, a call operation and a video information transmission / reception operation can be performed at the same time, and a still image transmission / reception operation and a video information transmission / reception operation can be performed at the same time.

【0100】

In addition, general-purpose data can be used to transmit data between other data terminal devices, for example, personal computers and telewriting terminals.

【0101】

FIG. 13 shows an example of the multiplexing / separation control device 45.

【0102】

In the figure, the bit clock CPb and the octet clock CPo are added to the synchronous control unit 70 that controls the operation of each unit of the multiplexing / separation control device 45. The received signals RD1 and RD2 are added to the loopback unit 71, and the transmitted signals TD1 and TD2 are output to an external device via the loopback unit 72.

【0103】

The loopback unit 71 selectively adds the received signals RD1 and RD2 to the loopback unit 72 or the synchronization unit 73,74 based on the control signal from the synchronization control unit 70. The frame synchronization signal FAS included in the input reception signals RD1 and RD2 is extracted to detect and hold the frame / multi-frame synchronization, and the FAS data DDf representing the contents of the frame synchronization signal FAS is output to the external device. In addition, the bit rate allocation signal BAS is extracted from the input received signals RD1 and RD2, and the BAS data DDb representing the contents is output to the BAS decoder 75. In the state where frame synchronization is maintained, received frame data is extracted from the input received signals RD1 and RD2 and output to the data buffers 76 and 77, respectively.

【0104】

Further, when the synchronization units 73 and 74 detect the multi-frame number 0, the multi-frame detection signal DD1 is generated, and the multi-frame detection signal DD1 is the time corresponding to n bits of the bit clock CPb by the delay circuit 78. In the delayed state, it is added to the data multiplexing unit 79 as a multi-frame timing signal DDm.

【0105】

Further, the synchronization units 73 and 74 form a frame synchronization signal at the extracted frame timing and form a multi-frame synchronization signal at the extracted multi-frame timing, and the frame synchronization signal and the multi-frame synchronization signal (multi-frame number). Is output to the synchronization control unit 70, and the multi-frame synchronization signal is output to the inter-channel synchronization unit 80. Further, the synchronization units 73 and 74 output the synchronization signal SYC at the frame synchronization timing.

【0106】

The BAS decoder 75 converts the BAS data DDb into the corresponding internal data, and the converted data is output to the external device as the received BAS data DDb'via the BAS buffer 81.

【0107】

The interchannel synchronization unit 80 receives frame data of the B1 channel added via the data buffer 76 based on the input frame synchronization signal and multi-frame synchronization signal in a state of being synchronized with the clock signal applied from the synchronization control unit 70. The purpose is to match the synchronization deviation of the received frame data in multi-frame units so that the multi-frame number and the multi-frame number of the received frame data of the B2 channel added via the data buffer 77 match. The B1 channel receive frame data FD1 and the B2 channel receive frame data FD2 matched in multi-frame units are added to the channel exchange unit 82.

【0108】

When the channel exchange command from the synchronization control unit 70 is output, the channel exchange unit 82 outputs the received frame data FD2 as the received frame data FD1a of the B1 channel, and also outputs the received frame data FD2 as the received frame data FD2a of the B2 channel. When the FD1 is output and the channel exchange command is not output from the synchronization control unit 70, the received frame data FD1 is output as the received frame data FD1a and the received frame data FD2 is output as the received frame data FD2a. These received frame data FD1a and FD2a are added to the data separation unit 83.

【0109】

The timing data generation unit 84 generates timing data TTb for data separation based on the control signal SS1 input from the external device and outputs the timing data TTb to the data separation unit 83, and also outputs the timing data TTg for data multiplexing. Is generated and output to the data multiplexing unit 79.

【0110】

The data separation unit 83 synchronizes with the clock signal applied from the synchronization detection unit 70, and based on the timing data TTb, receives audio data ODr, received video data VDr, and received general-purpose data PDra, from received frame data FD1a and FD2a. PDrb is extracted, and these received audio data ODr, received video data VDr, and received general-purpose data PDra and PDrb are output to an external device.

【0111】

The BAS encoder 85 forms a transmission BAS signal SS2 corresponding to the transmission BAS data DDba applied from an external device, and the transmission BAS signal SS2 is added to the data multiplexing unit 79.

【0112】

The data multiplexing unit 79 synchronizes with the clock signal applied from the synchronization detection unit 70, and based on the timing data TTg, the transmission voice data ODt, the transmission video data VDt, and the transmission general-purpose data PDta, PDtb added from the external device. Are multiplexed to form B1 channel transmission frame data FT1a and B2 channel transmission frame data FT2a.

【0113】

At the same time, the data multiplexing unit 79 arranges the transmission BAS signal SS2 in the bit rate allocation signal BAS of each frame data FT1a and FT2a, and transmits the transmission FAS signal SS3 input from the synchronization control unit 70 in each frame data FT1a. , FT2a frame synchronization signal Place in the corresponding bit position of FAS. The CRC bits included in the bit rate allocation signal BAS and the frame synchronization signal FAS are formed inside the data multiplexing unit 79, and these CRC bits correspond to each of the frame synchronization signal FAS and the bit rate allocation signal BAS. Place it at the bit position to be used.

【0114】

Then, when the transmission permission signal SS4 is output from the synchronization detection unit 70, the data multiplexing unit 79 outputs the formed transmission frame data FT1a and FT2a to the channel exchange unit 86. Further, when the transmission permission signal SS4 is not output from the synchronization detection unit 70, the transmission frame data FT1a and FT2a are not output to the channel exchange unit 86.

【0115】

When the channel exchange command is output from the synchronization control unit 70, the channel exchange unit 86 outputs the transmission frame data FT2a as the transmission frame data FT1 of the B1 channel and the transmission frame data FT1a as the transmission frame data FT2 of the B2 channel. Is output, and when the channel exchange command is not output from the synchronization control unit 70, the transmission frame data FT1a is output as the transmission frame data FT1 and the transmission frame data FT2a is output as the transmission frame data FT2. These transmission frame data FT1 and FT2 are output to an external device as transmission signals TD1 and TD2 via the loopback unit 72.

【0116】

Further, when the loopback command signal SS5 is output from the synchronization control unit 70, the loopback unit 72 returns the received signals RD1 and RD2 output from the loopback unit 71 as transmission signals TD1 and TD2.

【0117】

Therefore, when the reception operation is started, the reception signals RD1 and RD2 are added to the synchronization units 73 and 74 via the loopback unit 71, whereby the frame data of the reception signals RD1 and RD2 are added by the synchronization units 73 and 74. Frame synchronization detection operation is performed.

【0118】

In the synchronous detection state, as shown in FIG. 14, the synchronization units 73 and 74 output the multi-frame detection signal DD1 at the timing when the multi-frame number 0 is detected, and thereby the delay circuit 78 outputs the multi-frame detection signal DD1. , The multi-frame timing signal DDm is output to the data multiplexing unit 79 at the timing corresponding to n bits of the bit clock CPb elapses from the output timing.

【0119】

Here, since the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm receive the same received signal, the multiplexing / separation control device of the respective master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm. In 45, the multi-frame number 0 is detected at the same timing, and therefore, in the multiplexing / separation control device 45 of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm, the multi-frame timing signal is detected at the same timing. DDm is output.

【0120】

As a result, the transmission timings of the multi-frame numbers "0" of the transmission signals TD1 and TD2 match in all of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm, whereby all the master AV terminal device MSR and the slave AV terminal device MSR and The frame timings of the transmission signals TD1 and TD2 in the slave AV terminal devices SLV1 to SLVm are the same.

【0121】

FIG. 15 shows an example of processing performed by the master AV terminal device MSR at the start of transmission.

【0122】

First, the master AV terminal device MSR sets the multiplexing / separation control device 45 to the transmission permitted state, executes the call setting procedure for calling the partner station (process 110), and establishes the first channel. After establishing frame synchronization on the first channel (process 111) (process 112), data transmission using the first channel is started (process 113).

【0123】

Then, the additional call setting procedure is executed (process 114), the second channel is established (process 115), the frame synchronization on the second channel is established (process 116), and then the data transmission using the second channel is performed. Is started (process 117).

【0124】

In this way, first, with the master AV terminal device MSR having the transmission right, two information channels are established with the partner station, and data transmission using the two information channels is performed.

【0125】

FIG. 16 shows the processing performed by the slave AV terminal devices SLV1 to SLVm at the start of transmission.

【0126】

First, when the slave AV terminal devices SLV1 to SLVm are instructed to start data communication, the multiplexing / separation control device 45 is set to the transmission disallowed state, and only the reception operation is performed.

【0127】

Next, the master AV terminal device MSR performs a call setting operation for establishing the first channel, and when the first channel is established, the received signal of the first channel is obtained. Therefore, the received signal RD1 of the first channel is obtained. Frame synchronization detection / establishment operation is performed (process 121).

【0128】

As a result, the slave AV terminal devices SLV1 to SLVm start the reception operation of the same reception signal as the master AV terminal device MSR for the first channel (process 122).

【0129】

Then, the master AV terminal device MSR performs an additional call setting operation for establishing the second channel, and when the second channel is established, the received signal of the second channel is obtained. Therefore, the received signal RD2 is obtained for the second channel. Frame synchronization detection / establishment operation is performed (process 123).

【0130】

As a result, the slave AV terminal devices SLV1 to SLVm start the reception operation of the same reception signal as the master AV terminal device MSR for the second channel (process 124).

【0131】

In this way, the slave AV terminal devices SLV1 to SLVm are in the mode of monitoring the received signals RD1 and RD2 of the first channel and the second channel at the start of transmission, and the same audio and video as the master AV terminal device MSR are displayed. It is output.

【0132】

When the data transmission is started in this way, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm perform the processing of FIG. 17 to acquire / abandon the transmission right.

【0133】

That is, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm monitor that the operator operates the terminal switching key of the input device 59 (judgment 131), and the operator operates the terminal switching key to make a judgment. When the result of 131 becomes YES, it is determined whether or not the transmission is disabled until immediately before that and the transmission right is acquired by the terminal switching key (judgment 132).

【0134】

If the terminal switching key is operated while the transmission disabled state is set and the result of judgment 132 is YES, set the transmission permission state in the multiplexing / separation control device 45 (process 133), and then set the transmission permission state (process 133). Set the state so that the data transmission operation by the terminal can be performed, and return to the judgment 131.

【0135】

If the terminal switching key is operated while the transmission permission state is set and the result of the determination 132 is NO, the transmission disabled state is set in the multiplexing / separation control device 45 (process 134). , The state in which the data transmission operation by the own terminal cannot be performed, that is, the own terminal is set to the monitor mode, and the determination returns to 131.

【0136】

Therefore, in the data communication state, for example, when the transmission right is passed from the master AV terminal device MSR to the slave AV terminal device SLV1, the operator of the master AV terminal device MSR and the operator of the slave AV terminal device SLV1 are appropriate. Operate the terminal switching key of the input device 59 at the timing.

【0137】

As a result, for example, as shown in FIGS. 18 (a), (b), and (c), the master AV terminal device MSR and the slave AV terminal device SLV1 have a multi-frame number 3 and a multi-frame number 1, respectively. The operation timing of the terminal switching key occurs at the timing of.

【0138】

As a result, the multiplexing / separation control device 45 of the master AV terminal device MSR is set to the transmission disabled state at the timing of the multi-frame number "3", and the multiplexing / separation control unit 45 of the slave AV terminal device SLV1 is set. , The transmission permission status is set at the timing of the multi-frame number "1".

【0139】

As a result, the synchronization control unit 70 of the multiplexing / separation control unit 45 of the master AV terminal device MSR outputs the transmission permission signal SS4 output to the data multiplexing unit 79 at the timing of the next multi-frame number 0. The synchronization control unit 70 of the multiplexing / separation control device 45 of the slave AV terminal device SLV1 stops and outputs the transmission permission signal SS4 to the data multiplexing unit 79 at the timing of the next multi-frame number 0. ..

【0140】

As a result, as shown in Fig. (D), the content of the transmission signal output to the passive bus 21 at the timing of the multi-frame number "0" is changed from the transmission signal of the master AV terminal device MSR to the slave AV. The signal is switched to the transmission signal of the terminal device SLV1, and the operator of the slave AV terminal device SLV1 can communicate with the partner station.

【0141】

Further, when the transmission right is passed from the slave AV terminal device SLV1 that has acquired the transmission right to another slave AV terminal device SLV2 to SLVm or the master AV terminal device MSR, the same operation is performed to acquire the transmission right. / Abandonment is done properly.

【0142】

Here, when the B channel is used, the transmission time of one data frame is 10 milliseconds, so that the transmission time of one multi-frame is 160 milliseconds, and the 16-multi-frame interval is 2.56 seconds. Therefore, in the case of this embodiment, the time delay required from the operation of passing the transmission right by the operator to the actual transfer of the transmission right is a maximum of 2.56 seconds.

【0143】

As described above, in the present embodiment, the operators using the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm can appropriately obtain the right to speak and speak, so that the conference can proceed smoothly. it can.

【0144】

In addition, since multiple people can participate in the conference using one ISDN basic interface, the number of ISDN lines required to build a video conferencing system is significantly reduced, and the line cost is low. Can be realized.

【0145】

Further, since each master AV terminal device MSR and slave AV terminal devices SLV1 to SLVm can be realized with almost the same configuration as the videophone terminal, the device cost of the entire system can be reduced.

【0146】

Also, when the speaker changes, the camera angle does not change, so the image of the state in which the camera angle is being changed is not displayed on the video conferencing device on the other side, and therefore, a situation that causes camera sickness may occur. It does not occur and can prevent the participants of the conference from feeling uncomfortable.

【0147】

By the way, in the above-described embodiment, in order to match the frame synchronization states of the transmission signals of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm, the reception signal is transmitted with reference to the timing of the multi-frame number "0". The timing of the multi-frame number "0" of the signal is formed, but the method of matching the frame synchronization state of the transmitted signal is not limited to this.

【0148】

For example, the time difference between the multi-frame number "0" of the received signal and the multi-frame number "0" of the transmitted signal on the master AV terminal device MSR is detected, and the multi-frame number "0" of the slave AV terminal devices SLV1 to SLVm is detected. By matching the time difference of the multi-frame number "0" of the transmission signal with the detected time difference, the frame synchronization states of the transmission signals of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm can be matched.

【0149】

FIG. 19 shows a configuration example of the multiplexing / separation control device 45 of the master AV terminal device MSR in this embodiment. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

【0150】

In the figure, the synchronization control unit 70 forms a multi-frame synchronization signal DDk at the timing of the multi-frame number 0 independently of the multi-frame timing of the received signal, and data-multiplexes the multi-frame synchronization signal DDk. It is output to unit 79 and delay amount detection unit 87.

【0151】

The delay amount detection unit 87 bit clocks the time from the detection of the multi-frame detection signal DD1 output from the synchronization units 73 and 74 to the detection of the multi-frame synchronization signal DDk output from the synchronization control unit 70. It is detected as the number of bits of CPb, and the detection result is output as the delay amount detection value DLd.

【0152】

This delay amount detection value DLd is transferred to the system control unit 60 via the multiplexing / separation control unit 49, whereby the system control unit 60 sets the value corresponding to the input delay amount detection value DLd to the current value. It is displayed on the display device 61 as the delay amount in the communication state.

【0153】

FIG. 20 shows a configuration example of the multiplexing / separation control device 45 of the slave AV terminal devices SLV1 to SLVm. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

【0154】

In the figure, delay amount setting values DLs are added to the delay circuit 88 by the multiplexing / separation control unit 49, and the delay circuit 88 outputs the multi-frame detection signal DD1 from the synchronization units 73 and 74. When input, the multi-frame timing signal DDm is output at the timing when the number of bits of the bit clock CPb corresponding to the delay amount set value DLs has elapsed from the input timing.

【0155】

With the above configuration, when the call setting operation by the master AV terminal device MSR is performed and the data transmission operation by the two information channels is started, the multiplexing / separation control unit 49 of the master AV terminal device MSR is multiplexed. / Input the delay amount detection value DLd output from the separation control device 45 and transfer it to the system control unit 60.

【0156】

As a result, the system control unit 60 displays the value corresponding to the input delay amount detection value DLd on the display device 61 as the delay amount in the current communication state.

【0157】

The operator who confirmed this display notifies the displayed delay amount for each operator of the slave AV terminal devices SLV1 to SLVm, and each operator of the slave AV terminal devices SLV1 to SLVm operates the input device 59 of the own terminal. And enter the notified delay amount.

【0158】

As a result, the system control unit 60 of each slave AV terminal device SLV1 to SLVm multiplexes / separates the delay amount set value DLs corresponding to the input delay amount via the multiplexing / separation control unit 49. Output to.

【0159】

As a result, the value of the delay amount setting value DLs input to the delay circuit 88 of the multiplexing / separation control device 45 of each slave AV terminal device SLV1 to SLVm is the detection timing of the multi-frame detection signal DD1 in the master AV terminal device MSR. The value corresponds to the delay time from to the detection timing of the multi-frame synchronization signal DDk, and as a result, the frame timing of the transmission signals TD1 and TD2 output from each slave AV terminal device SLV1 to SLVm is the master AV terminal device MSR. It matches the frame timing of the transmission signals TD1 and TD2 output from.

【0160】

FIG. 21 shows the configuration of a home station of a video conferencing system according to another embodiment of the present invention. In the figure, the same parts as those in FIG. 10 and the corresponding parts are designated by the same reference numerals.

【0161】

In the figure, the master AV terminal device MSR outputs the timing signal TMt representing the multi-frame number 0 of the transmission signal to each slave AV terminal device SLV1 to SLVm, and each slave AV terminal device SLV1 to SLVm. Then, in synchronization with this timing signal TMt, the timing of the multi-frame number "0" of the transmission signal of the own terminal is set.

【0162】

FIG. 22 shows a configuration example of the master AV terminal device MSR of FIG. In the figure, the same parts as those in FIG. 12 and the corresponding parts are designated by the same reference numerals.

【0163】

In the figure, the multiplexing / separation control device 45 outputs a timing signal TM at the timing of the multi-frame number 0 of the transmission signal, and this timing signal TM is transmitted to each slave via the output circuit 90. It is output as a timing signal TMt to the AV terminal devices SLV1 to SLVm.

【0164】

FIG. 23 shows a configuration example of the multiplexing / separation control device 45 of the master AV terminal device MSR of FIG. 21. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

【0165】

In the figure, the synchronization control unit 70 independently performs a synchronization operation, forms a multi-frame synchronization signal DDl at the timing of the multi-frame number 0 in the operation, and uses this multi-frame synchronization signal DDl as a data multiplexing unit. In addition to adding to 79, it is output to an external device as a timing signal TM.

【0166】

The slave AV terminal devices SLV1 to SLVm of FIG. 21 have the same configuration as the AV terminal device shown in FIG. 12, and a configuration example of the multiplexing / separation control device 45 thereof is shown in FIG. In the figure, the same parts as those in FIG. 13 and the corresponding parts are designated by the same reference numerals.

【0167】

In the figure, the timing signal TMt applied from the master AV terminal device MSR is added to the data multiplexing unit 79 as a multi-frame synchronization signal, whereby the data multiplexing unit 79 is multiplexed by the master AV terminal device MSR. It operates at the same frame timing as the data multiplexing unit 79 in the conversion / separation control device 45.

【0168】

As a result, the frame timings of the transmission signals TD1 and TD2 output from the slave AV terminal devices SLV1 to SLVm match the frame timings of the transmission signals TD1 and TD2 output from the master AV terminal device MSR.

【0169】

FIG. 25 shows the configuration of a home station according to another embodiment of the present invention. In the figure, the same parts as those in FIG. 10 and the corresponding parts are designated by the same reference numerals.

【0170】

In this embodiment, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm are connected via the local area network LAN, and various information is exchanged using the local area network LAN.

【0171】

In this case, as shown in FIG. 26, the signal format of the information exchanged via the local area network LAN (hereinafter referred to as command data) is the destination identification information for specifying the reception destination of this command data, and this command data. It consists of source identification information that represents the terminal that sent the command, command identification information that represents the command type, and additional information that represents additional information required for the command.

【0172】

The command identification information consists of two-digit hexadecimal numbers, and Fig. 27 shows an example of the relationship between the command type and the command identification information.

【0173】

In this case, the data 41H (H represents a hexadecimal number; the same applies hereinafter) represents the "send permission" command that passes the transmission right to the terminal device of the identification information set in the additional information, and the data 42H is set in the additional information. Represents the "delay amount notification" command that specifies that the set value is set to the delay time from the reception of the multi-frame number "0" of the received signal to the output of the transmission signal of the multi-frame number "0".

【0174】

The signal format of the command data is not limited to this. Further, the above-mentioned types of command types are presented only for the portion related to this embodiment, and moreover, many types of commands (for example, history storage of the terminal state) can be provided.

【0175】

FIG. 28 shows a configuration example of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm shown in FIG. In the figure, the same parts as those in FIG. 12 and the corresponding parts are designated by the same reference numerals.

【0176】

In the figure, the LAN interface circuit 91 realizes functions (signal transmission / reception function, protocol function, etc.) for exchanging various data via a local area network LAN, and is connected to the system control unit 60. ing.

【0177】

Here, in this embodiment, the multiplexing / separation control device 45 includes the same one as shown in FIG. 13, whereby the transmission signals of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm are transmitted. The frame timing is the same.

【0178】

That is, in this case, the transmission signal with the multi-frame number "0" is output at the timing when the delay time corresponding to n bits of the bit clock CPb elapses after the multi-frame number "0" of the received signal is detected. Will be done.

【0179】

Further, in this embodiment, the master AV terminal device MSR notifies the slave AV terminal devices SLV1 to SLVm of the transfer of transmission right using the local area network LAN, and the master AV terminal device MSR in that case. A processing example of is shown in FIG.

【0180】

In the figure, the master AV terminal device MSR monitors whether the input device 59 is operated and the operator requests switching of the transmitting terminal (NO loop of judgment 201), and the operator of the master AV terminal device MSR. When (that is, the chairman or the proceedings) performs an operation of passing the transmission right to the transmitting terminal of the speaker (including himself / herself) in order to change the speaker, the result of the judgment 201 becomes YES and the master AV terminal device. The MSR creates the command data of the "permit transmission" command to be sent on the local area network LAN (process 202).

【0181】

In this case, the destination identification information is set to specific terminal identification information for designating all terminals, the source identification information is set to the terminal identification information representing the own terminal, and the command identification information is "send permission". Set the data 41H that represents the command, and set the terminal identification information that represents the newly specified transmitting terminal in the additional information.

【0182】

Then, the created command data is sent to the local area network LAN via the LAN interface circuit 91 (process 203).

【0183】

On the other hand, when the slave AV terminal devices SLV1 to SLVm receive the command data from the local area network LAN, they perform the processing as shown in FIG.

【0184】

That is, the slave AV terminal devices SLV1 to SLVm are monitoring the reception of command data from the local area network LAN (NO loop of judgment 211), and receive the command data from the local area network LAN and the result of judgment 211. If is YES, check whether the command data is a "send allow" command (judgment 212).

【0185】

When the result of judgment 212 is YES, it is checked whether the terminal identification information set in the additional information matches the terminal identification information of the own terminal (judgment 213), and when the result of judgment 213 is YES, It is determined that the local terminal has acquired the transmission right, and the data transmission permission state is set in the multiplexing / separation control device 45 via the multiplexing / separation control unit 49 (process 214).

【0186】

When the result of the determination 213 is NO, it is determined that the own terminal does not acquire the transmission right, and the data transmission disabled state is set in the multiplexing / separation control device 45 via the multiplexing / separation control unit 49. (Processing 215).

【0187】

If the received command data is other than the "permit transmission" command and the result of judgment 212 is NO, the process corresponding to the received command data is performed (process 216).

【0188】

In this way, when the master AV terminal device MSR specifies the terminal device to newly acquire the transmission right by the "transmission permission" command and notifies each slave AV terminal device SLV1 to SLVm via the local area network LAN. , The slave AV terminal devices SLV1 to SLVm specified at that time start transmitting the transmission signal at the timing of the next multi-frame number "0" after receiving the command data, and the other slave AVs. The terminal devices SLV1 to SLVm stop transmitting the transmission signal from the timing of the next multi-frame number "0" after receiving the command data.

【0189】

When the master AV terminal device MSR acquires the transmission right, the master AV terminal device MSR starts transmitting the transmission signal at the timing of the next multi-frame number "0" after transmitting the command data. When the transmission right is transferred from the master AV terminal device MSR to the other slave AV terminal devices SLV1 to SLVm, the master AV terminal device MSR sends the command data and then the next multi-frame number "0". The transmission of the transmission signal is stopped at the timing of.

【0190】

As described above, in this embodiment, since the transfer of the transmission right is notified via the local area network LAN, the operator of the slave AV terminal devices SLV1 to SLVm at the time of the transfer of the transmission right does not need to be troubled.

【0191】

By the way, in the above-described embodiment, the transmission signal having the multi-frame number 0 is transmitted at the timing when the delay time corresponding to n bits of the bit clock CPb elapses after the multi-frame number 0 of the received signal is detected. Although it is intended to be transmitted, the slave AV terminal device determines the delay time from the detection of the multi-frame number "0" of the received signal on the master AV terminal device MSR to the transmission of the transmission signal of the multi-frame number "0". It may be set to SLV1 to SLVm.

【0192】

In this case, the configuration of the multiplexing / separation control device 45 of the master AV terminal device MSR is the same as that of FIG. 19, and the configuration of the multiplexing / separation control device 45 of the slave AV terminal devices SLV1 to SLVm is It will be the same as shown in FIG.

【0193】

In this case, FIG. 31 shows an example of processing when the master AV terminal device MSR notifies the slave AV terminal devices SLV1 to SLVm of the delay time.

【0194】

First, when the call connection with the partner station is completed, the master AV terminal device MSR waits until the frame synchronization of the information channel is established (NO loop of judgment 220), and the synchronization establishment is completed and the result of judgment 220 is When YES, the delay amount detection value DLd output from the multiplexing / separation control device 45 is input (process 221) via the multiplexing / separation control unit 49, and the delay amount sent on the local area network LAN is sent. Create command data for the "Notification" command (process 222).

【0195】

In this case, specific terminal identification information for designating all terminals is set in the destination identification information, terminal identification information representing the own terminal is set in the source identification information, and "delay amount" is set in the command identification information. Set the data 42H that represents the "notification" command, and set the input delay amount detection value DLd value in the additional information.

【0196】

Then, the created "delay amount notification" command is sent to the local area network LAN via the LAN interface circuit 91 (process 223).

【0197】

The master AV terminal device MSR performs the same processing as in FIG. 29 when the transfer of the transmission right is specified, as in the above-described embodiment.

【0198】

FIG. 32 shows an example of the processing performed by the slave AV terminal devices SLV1 to SLVm when the command data is received via the local area network LAN.

【0199】

The slave AV terminal devices SLV1 to SLVm are monitoring the reception of command data via the local area network LAN (NO loop of judgment 231), and when the result of judgment 231 is YES after receiving the command data, Check whether the received command data is a "delay amount" command (judgment 232).

【0200】

When the result of determination 232 is YES, the value set in the additional information of the command data is notified to the multiplexing / separation control device 45 as the delay amount set value DLs via the multiplexing / separation control unit 49. (Processing 233).

【0201】

As a result, in the slave AV terminal devices SLV1 to SLVm, the delay time from the detection of the multi-frame number "0" of the received signal to the transmission of the transmission signal of the multi-frame number "0" is determined in the master AV terminal device MSR. It becomes equal to the delay time, and the synchronization timing of the transmission signals of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm matches.

【0202】

Also, when the received command data is not a "delay amount notification" command and the result of judgment 232 is NO, it is checked whether the received command data is a "send permission" command (judgment 234).

【0203】

When the result of judgment 234 is YES, it is checked whether the terminal identification information set in the additional information matches the terminal identification information of the own terminal (judgment 235), and when the result of judgment 235 is YES, it is self. It is determined that the terminal has acquired the transmission right, and the data transmission permission state is set in the multiplexing / separation control device 45 via the multiplexing / separation control unit 49 (process 236).

【0204】

When the result of the determination 235 is NO, it is determined that the own terminal does not acquire the transmission right, and the data transmission disabled state is set in the multiplexing / separation control device 45 via the multiplexing / separation control unit 49. (Processing 237).

【0205】

If the received command data is other than the "delay amount notification" command or the "send permission" command and the result of judgment 234 is NO, the process corresponding to the received command data is performed (process 238).

【0206】

The operation of moving the transmission right of the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm in this embodiment is the same as that in the above-described embodiment.

【0207】

FIG. 33 shows the system configuration of the home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 25 and the corresponding parts are designated by the same reference numerals.

【0208】

In this embodiment, the master AV terminal device MSR and the slave AV terminal devices SLV1 to SLVm are connected via the local area network LAN, and the transmission signal is transmitted from the master AV terminal device MSR to each slave AV terminal device SLV1 to SLVm. The timing signal TMt that represents the timing of the multi-frame number "0" is output.

【0209】

FIG. 34 shows the configuration of the master AV terminal device MSR in this embodiment. In the figure, the same parts as those in FIG. 28 and the corresponding parts are designated by the same reference numerals. Further, the configurations of the slave AV terminal devices SLV1 to SLVm in this embodiment are the same as those in FIG. 28.

【0210】

In the figure, the multiplexing / separation control device 45 outputs a timing signal TM at the timing of the multi-frame number 0 of the transmission signal, and this timing signal TM is transmitted to each slave via the output circuit 90. It is output as a timing signal TMt to the AV terminal devices SLV1 to SLVm.

【0211】

Further, the configuration of the multiplexing / separation control device 45 of the master AV terminal device MSR in this embodiment is the same as that of FIG. 23, and the configuration of the multiplexing / separation control device 45 of the slave AV terminal devices SLV1 to SLVm. Is the same as that of FIG.

【0212】

Further, also in this embodiment, the method of instructing the slave AV terminal devices SLV1 to SLVm from the master AV terminal device MSR to acquire / abandon the transmission right via the local area network LAN is the same method as in the above-described embodiment. Can be used (see Figures 29 and 30).

【0213】

In the above-described embodiment, the case where a wired local area network LAN is used as the local area network LAN has been described, but a wireless local area network LAN can also be used. In that case, the signal delay amount in the local area network LAN becomes almost 0. Therefore, for example, the timing signal indicating the timing of the multi-frame number "0" from the master AV terminal device MSR to the slave AV terminal devices SLV1 to SLVm. Is transmitted via the local area network LAN, and the slave AV terminal devices SLV1 to SLVm transmit the transmission signal with the multi-frame number "0" at the timing that matches the timing signal, thereby transmitting the master AV terminal device MSR and The frame timings of the transmission signals of the slave AV terminal devices SLV1 to SLVm can be matched.

【0214】

FIG. 35 shows the system configuration of the home station according to still another embodiment of the present invention.

【0215】

In the figure, the network control terminal device 92 terminates the ISDN basic interface and is connected to the line interface circuit 94 via the transformer 93.

【0216】

The line interface circuit 94 separates the received signal of the ISDN basic interface and outputs it to the layer 1/2 control device 95, and sends the transmission signal output from the layer 1/2 control device 95 to the ISDN basic interface. is there.

【0217】

The layer 1/2 controller 95 controls the signals of layer 1 and layer 2 of the ISDN basic interface, and separates / integrates the signals of the two information channels and one signal channel multiplexed on the transmitted / received signals. The signal SDc on the signal channel is output to a plurality of AV terminal devices ATE1 to ATEm.

【0218】

In addition, the received signal RD1 of the B1 channel, the received signal RD2 of the B2 channel, the bit clock CPb representing the bit timing of the received signals RD1 and RD2, and the octet of the received signals RD1 and RD2 separated by the layer 1/2 controller 95. The octet clock CPo that represents the timing is output to the AV terminal devices ATE1 to ATEm, respectively.

【0219】

Further, the B1 channel transmission signal TD1 and the B2 channel transmission signal TD2 output from the AV terminal devices ATE1 to ATEm are added to the selection circuit 96 and the selection circuit 97, respectively.

【0220】

The selection circuit 96 and the selection circuit 97 select the transmission signal TD1 and the transmission signal TD2 output from the AV terminal devices ATE1 to ATEm based on the selection signal SLa output from the control unit 98, and select them respectively. The transmitted transmission signal TD1 and transmission signal TD2 are output to the layer 1/2 control device 95 as transmission signal TD1a and transmission signal TD2a. Further, the timing of switching the selected transmission signals TD1 and TD2 is performed at the beginning of any of the sub-multiframes as described above. This sub-multiframe timing is output from one of the AV terminal devices ATE1 to ATEm to the selection circuits 96 and 97 (not shown).

【0221】

The operation display unit 99 selects and operates the AV terminal devices ATE1 to ATEm that give the transmission right and displays the selected state. The operation signal is output to the control unit 98 and the control unit. The display signal has been added since 98.

【0222】

The control unit 98 forms a selection signal SLa for selecting the designated AV terminal devices ATE1 to ATEm based on the operation signal output from the operation display unit 99, and outputs the selection signals to the selection circuits 96 and 97. , A display signal for displaying the selected state is formed and output to the operation display unit 99.

【0223】

FIG. 36 shows a configuration example of the AV terminal devices ATE1 to ATEm. In the figure, the same parts as those in FIG. 12 and the corresponding parts are designated by the same reference numerals.

【0224】

In the figure, the D channel layer 3 control unit 44 exchanges the signal SDc on the signal channel with the layer 1/2 control device 95, and the multiplexing / separation control device 45 has layer 1 /. 2 Received signals RD1 and RD2, bit clock CPb and octet clock CPo output from the control device 95 are added, and transmission signals TD1 and TD2 output from the multiplexing / separation control unit 45 are selected circuits 96 and 97, respectively. It is output to.

【0225】

Here, as a method of matching the frame timings of the transmission signals of the AV terminal devices ATE1 to ATEm, when a time corresponding to n bits of the bit clock CPb elapses from the timing of the multi-frame number "0" of the reception signal, When the method of transmitting the transmission signal of the multi-frame number 0 is used, the one shown in FIG. 13 can be used as the multiplexing / separation control unit 45.

【0226】

With the above configuration, when performing video conference communication between the home station and the partner station, the chairman of the conference or the proceedings operator operates the operation display unit 99 to select, for example, the AV terminal device ATE1.

【0227】

As a result, the control unit 98 outputs the selection signal SLa for selecting the AV terminal device ATE1, causes the selection circuits 96 and 97 to select the transmission signals TD1 and TD2 of the AV terminal device ATE1, respectively, thereby causing the AV terminal device ATE1. The transmission signals TD1 and TD2 of the above are added to the layer 1/2 control device 95 as transmission signals TD1a and TD2a, respectively, and the AV terminal device ATE1 can operate the communication.

【0228】

At the same time, the control unit 98 forms a display signal indicating that the AV terminal device ATE1 is selected and outputs the display signal to the operation display unit 99, whereby the AV terminal device ATE1 is output to the operation display unit 99. Is displayed as being selected.

【0229】

After confirming this display, the chairman or the proceedings operator operates the AV terminal device ATE1 to call the partner station, whereby the call setting procedure is performed between the AV terminal device ATE1 and the partner station. Two information channels are sequentially established, and frame synchronization on each information channel is detected and established.

【0230】

On the other hand, the other AV terminal devices ATE2 to ATEm receive the received signals RD1 and RD2 output from the layer 1/2 control device 95, and each AV terminal device ATE2 to ATEm independently transmits the transmission signals TD1 and TD1. Performs TD2 output operation.

【0231】

As a result, the same audio signal as the AV terminal device ATE1 is output to the AV terminal devices ATE2 to ATEm, and the video is displayed and output.

【0232】

Then, for example, when a conference participant using the AV terminal device ATE2 requests a statement and it is accepted by the chairman or the proceedings, the chairman or the proceedings operates the operation display unit 99. Select the AV terminal device ATE2.

【0233】

As a result, the control unit 98 outputs the selection signal SLa for selecting the AV terminal device ATE2, whereby the selection circuits 96 and 97 select the transmission signals TD1 and TD1 at the start timing of the submultiframe immediately after. Switch the TD2 from that of the AV terminal device ATE1 to that of the AV terminal device ATE2.

【0234】

As a result, the transmission signals TD1 and TD2 of the AV terminal device ATE2 are set to be added to the layer 1/2 control device 95 as transmission signals TD1a and TD2a. Further, before and after the switching of the transmission signals TD1 and TD2, the synchronization state of the transmission signals TD1 and TD2 is not disrupted.

【0235】

At the same time, the control unit 98 forms a display signal indicating that the AV terminal device ATE2 is selected and outputs the display signal to the operation display unit 99, whereby the AV terminal device ATE2 is output to the operation display unit 99. Is displayed as being selected. In this way, the transmission signals TD1 and TD2 from the AV terminal device ATE2 of the participant who requested the remark are transmitted to the partner station, and the remark content of the speaker is output to the partner station.

【0236】

In this way, in this embodiment, the AV terminal devices ATE1 to ATEm perform transmission / reception operations in a synchronized state, and the transmission signal of any one AV terminal device ATE1 to ATEm is effectively output to the partner station. Will be done.

【0237】

By the way, as a method of matching the frame timings of the transmission signals of the AV terminal devices ATE1 to ATEm, for example, the multi-frame number "0" of the received signal and the multi-frame number "0" of the transmission signal in the specific AV terminal device ATE1. It is possible to use a method of detecting the time difference between the two and matching the time difference between the multi-frame number "0" of the other AV terminal devices ATE2 to ATEm and the multi-frame number "0" of the transmission signal to the detected time difference. In that case, the one shown in FIG. 19 is used as the multiplexing / separation control device 45 of the specific AV terminal device ATE1, and FIG. 20 is used as the multiplexing / separation control device 45 of the other AV terminal devices ATE2 to ATEm. Use the one.

【0238】

Then, the specific AV terminal device ATE1 performs the call setting and frame synchronization detection / establishment operation of the information channel, and when the frame synchronization is completed, the value of the delay time displayed on the display device 61 of the AV terminal device ATE1 is set. A user of other AV terminal devices ATE2 to ATEm inputs using the input device 59.

【0239】

As a result, in the AV terminal devices ATE2 to ATEm, the value of the delay time input by the system control unit 60 is set in the multiplexing / separation control unit 45 via the multiplexing / separation control unit 49, and as a result, all The frame timings of the transmission signals match in the AV terminal devices ATE1 to ATEm.

【0240】

FIG. 37 shows the system configuration of the home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 35 and the corresponding parts are designated by the same reference numerals.

【0241】

In the figure, the control unit 98 generates a timing signal TMm at a time interval (= 2.56 seconds) corresponding to a 16 multi-frame interval, and the timing signal TMm is added to the AV terminal devices ATE1 to ATEm, respectively.

【0242】

FIG. 38 shows a configuration example of the AV terminal devices ATE1 to ATEm. In the figure, the same parts as those in FIG. 36 or the parts corresponding to those in FIG. 36 are designated by the same reference numerals.

【0243】

In the figure, a timing signal TMm output from the control unit 98 is added to the multiplexing / separation control device 45. Further, in this case, as the multiplexing / separation control device 45, the one having the same configuration as that in FIG. 24 is used.

【0244】

That is, in this embodiment, the control unit 98 generates a timing signal TMm that defines the timing of the multi-frame number 0 and adds it to the AV terminal devices ATE1 to ATEm, so that each AV terminal device ATE1 to ATEm The frame timings of the transmitted signals are matched.

【0245】

Since the selection operation and communication operation of the AV terminal devices ATE1 to ATEm in this case are the same as those shown in FIG. 35, the description thereof will be omitted.

【0246】

FIG. 39 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 35 and the corresponding parts are designated by the same reference numerals.

【0247】

In the figure, the transmission signal synchronization units 101 and 102 perform the multi-frame number 0 of the other AV terminal devices ATE2 to ATEm at the timing of the multi-frame number 0 of the transmission signals TD1 and TD2 output from the AV terminal device ATE1. The transmission signals TD1 and TD2 of the AV terminal devices ATE2 to ATEm are buffered and output to the selection circuits 96 and 97 so that the timings of "" match.

【0248】

Therefore, the transmission signals TD1 and TD2 of the AV terminal devices ATE1 to ATEm are output to the selection circuits 96 and 97 in a state where the timing is adjusted so that the frame timings match.

【0249】

Further, in this case, the AV terminal devices ATE1 to ATEm can output the transmission signals TD1 and TD2 at independent timings, and the multiplexing / separation control device 45 applied to the AV terminal devices ATE1 to ATEm. An example is shown in FIG. In the figure, the same parts as those in FIG. 23 are designated by the same reference numerals.

【0250】

In the figure, the synchronization control unit 70 independently performs a synchronization operation, forms a multi-frame synchronization signal DDl at the timing of the multi-frame number 0 in the operation, and uses this multi-frame synchronization signal DDl as a data multiplexing unit. Add to 79.

【0251】

Since the selection operation and communication operation of the AV terminal devices ATE1 to ATEm in this case are the same as those shown in FIG. 35, the description thereof will be omitted.

【0252】

FIG. 41 shows a system configuration of a home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 10 and the corresponding parts are designated by the same reference numerals.

【0253】

In the figure, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm are connected to the passive bus 21, and the master AV terminal device MTR to the slave AV terminal devices SLA1 to SLAm have two information channels. The above received signal RD, bit clock CPb and octet clock CPo are added, and the transmission signal TD on the two information channels is added from the slave AV terminal devices SLA1 to SLAm to the master AV terminal device MTR.

【0254】

FIG. 42 shows a configuration example of the master AV terminal device MTR. In the figure, the same parts as those in FIG. 12 and the corresponding parts are designated by the same reference numerals.

【0255】

In the figure, the socket 105 connects the master AV terminal device MTR to the passive bus 21, and the received signals RD1 and RD2, the bit clock CPb, and the octet clock CPo output from the layer 1/2 control device 43 are , It is added to the multiplexing / separation control device 45, and is output to the slave AV terminal devices SLA1 to SLAm.

【0256】

Further, the transmission signals TD1 and TD2 output from the multiplexing / separation control device 45 are added to the transmission signal selection circuit 106, and the transmission signal selection circuit 106 is connected to the slave AV terminal devices SLA1 to SLAm. The output transmission signal TD is added.

【0257】

FIG. 43 shows a configuration example of the slave AV terminal devices SLA1 to SLAm. In the figure, the same parts as those in FIG. 42 and the corresponding parts are designated by the same reference numerals.

【0258】

In the figure, the signal switch 107 is a reception signal RD1 and RD2 output from the layer 1/2 control device 43, a bit clock CPb, an octet clock CPo, and a reception signal RD1 output from the master AV terminal device MTR. , RD2, bit clock CPb, and octet clock CPo are switched and added to the multiplexing / separation control device 45 as received signals RD1, RD2, bit clock CPb, and octet clock CPo, respectively, and the multiplexing / separation control device. The transmission signals TD1 and TD2 output from 45 are output to either the layer 1/2 control device 43 or the master AV terminal device MTR. When the layer 1/2 control device 43 is selected, the signal SDc on the signal channel output from the layer 1/2 control device 43 is exchanged with the D channel layer 3 control unit 44.

【0259】

Further, in this embodiment, the multiplexing / separation control device 45 of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm is used as shown in FIG.

【0260】

With the above configuration, when performing video conference communication between the home station and the partner station, the user of the master AV terminal device MTR (for example, the chairman or the proceedings) sets his own terminal as the transmitting terminal. In addition, the user of each slave AV terminal device SLA1 to SLAm is set to connect to the master AV terminal device MTR.

【0261】

As a result, in the master AV terminal device MTR, the system control unit 60 selects the transmission signals TD1 and TD2 output from the multiplexing / separation control device 45 by the transmission signal selection circuit 106, and sets the layer 1/2 control device 43. It outputs, and as a result, the data communication operation by the master AV terminal device MTR becomes possible.

【0262】

Further, the slave AV terminals SLA1 ~ SLAM, master AV terminal device system control unit 60 by the signal switching device 107 selects the location MTR, thereby, the multiplexing / demultiplexing control unit 45, via the signal switching device 107 The reception signals RD1 and RD2 from the master AV terminal device MTR, the bit clock CPb, and the octet clock CPo are added, and the transmission signals TD1 and TD2 output from the multiplexing / separation control device 45 are signal switch 107. It is output to the master AV terminal device MTR via.

【0263】

At this time, the signal SDc is not exchanged between the D channel layer 3 control unit 44 of the slave AV terminal devices SLA1 to SLAm and the layer 1/2 control device 43, so that the slave AV terminal devices SLA1 to SLAm are not exchanged. Cannot perform independent call setting operations.

【0264】

In this state, the master AV terminal device MTR calls the other station, the call setting operation is performed, the two information channels are established, and the frame synchronization detection / establishment of the two information channels is performed.

【0265】

On the other hand, the slave AV terminal devices SLA1 to SLAm perform the reception operation of the received signal RD and, as described above, independently perform the transmission operation at the same frame timing as the master AV terminal device MTR. However, in this case, only the transmission signal TD of the master AV terminal device MTR is selected and output to the passive bus 21.

【0266】

Therefore, the transmission operation by the master AV terminal device MTR is effectively performed, and the slave AV terminal devices SLA1 to SLAm output the same audio as that received by the master AV terminal device MTR and display and output the video. Will be done.

【0267】

In this state, for example, when the user of the slave AV terminal device SLA1 requests and accepts a statement and the user of the master AV terminal device MTR operates and inputs to switch to the slave AV terminal device SLA1, the master AV terminal device The system control unit 60 of the MTR switches the selected transmission signal TD from the multiplexing / separation control device 45 to the transmission signal TD of the slave AV terminal device SLA1 by the transmission signal selection circuit 106 at the start timing of the sub-multiframe.

【0268】

As a result, the transmission signal TD of the slave AV terminal device SLA1 used by the speaker is output to the passive bus 21 and received at the partner station.

【0269】

In this way, the transmission signal TD of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm is selected by the transmission signal selection circuit 106 according to the speaker, whereby the master AV terminal device MTR and the slave AV terminal are selected. The remarks of the users of the devices SLA1 to SLAm can be transmitted to the partner station.

【0270】

In addition to the video conferencing communication described above, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm can also perform communication operations independently.

【0271】

In this case, the user of the slave AV terminal devices SLA1 to SLAm commands the passive bus 21 to be connected by using the input device 59.

【0272】

As a result, the control unit 60 of the slave AV terminal devices SLA1 to SLAm multiplexes the received signals RD1 and RD2, the bit clock CPb, and the octet clock CPo output from the layer 1/2 control device 43 by the signal switch 107. The transmission signals TD1 and TD2 output from the multiplexing / separation control device 45 are added to the layer 1/2 control device 43 while being added to the conversion / separation control device 45. At the same time, the signal SDc on the signal channel can be exchanged between the layer 1/2 control device 43 and the D channel layer 3 control unit 44.

【0273】

As a result, the slave AV terminal devices SLA1 to SLAm are in a state where they can independently perform the call setting operation and the data transmission operation.

【0274】

By the way, as a method of matching the frame timings of the transmission signals of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm, for example, the multi-frame number "0" of the received signal in the master AV terminal device MTR and the multi-transmission signal are multi. A method is used in which the time difference of the frame number "0" is detected and the time difference between the multi-frame number "0" of the slave AV terminal devices SLA1 to SLAm and the multi-frame number "0" of the transmission signal is matched with the detected time difference. In that case, the one shown in FIG. 19 is used as the multiplexing / separation control device 45 of the master AV terminal device MTR, and FIG. 20 is used as the multiplexing / separation control device 45 of the slave AV terminal devices SLA1 to SLAm. Use the one.

【0275】

Then, the master AV terminal device MTR performs call setting and frame synchronization detection / establishment operation of the information channel, and when the frame synchronization is completed, the delay time value displayed on the display device 61 of the master AV terminal device MTR is set to the slave. The user of the AV terminal devices SLA1 to SLAm inputs using the input device 59.

【0276】

As a result, in the slave AV terminal devices SLA1 to SLAm, the system control unit 60 sets the input delay time value to the multiplexing / separation control unit 45 via the multiplexing / separation control unit 49, and as a result, the result is as follows. The frame timings of the transmission signals match in the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm.

【0277】

FIG. 44 shows a configuration example of the master AV terminal device MTR according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 42 are designated by the same reference numerals. Further, this embodiment is applied to a home station having the same system configuration as that shown in FIG. 41.

【0278】

In the figure, the transmission signal synchronization selection circuit 108 has the multi-frame numbers of the slave AV terminal devices SLA1 to SLAm at the timing of the multi-frame number 0 of the transmission signals TD1 and TD2 output from the multiplexing / separation control device 45. The transmission signals TD of the slave AV terminal devices SLA1 to SLAm are buffered so that the timing of "0" matches, and the transmission signals TD1 and TD2 and the slave AV terminal device SLA1 output from the multiplexing / separation control device 45 are buffered. The transmission signal TD output from ~ SLAm is selected and output to the layer 1/2 controller 43.

【0279】

Further, in this case, the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm can output the transmission signals TD1 and TD2 at independent timings, and therefore, the master AV terminal device MTR and the slave AV terminal. As the multiplexing / separation control device 45 applied to the devices SLA1 to SLAm, the same configuration as that shown in FIG. 40 can be used.

【0280】

FIG. 45 shows the system configuration of the home station according to still another embodiment of the present invention. In the figure, the same parts as those in FIG. 41 and the corresponding parts are designated by the same reference numerals.

【0281】

In this embodiment, the master AV terminal device MTR generates a timing signal TMm at the timing of the multi-frame number 0, and the timing signal TMm is added to the slave AV terminal devices SLA1 to SLAm.

【0282】

In this case, as the multiplexing / separation control device 45 of the master AV terminal device MTR, the one having the same configuration as that shown in FIG. 23 can be used, and the multiplexing / separation of the slave AV terminal devices SLA1 to SLAm. As the control device 45, one having the same configuration as that shown in FIG. 24 can be used.

【0283】

Since the operations of the master AV terminal device MTR and the slave AV terminal devices SLA1 to SLAm in this embodiment are the same as those shown in FIG. 41, the description thereof will be omitted.

【0284】

By the way, in the above-described embodiment, the home station directly connected to the basic interface of ISDN has been described, but the present invention also applies to the home station connected to the basic interface on the extension side of the premises exchange device. Can be applied.

【0285】

Further, the configuration of each AV terminal device is not limited to the one described above. Further, in the above description, the description of the portion not directly related to the present invention is omitted.

【0286】

[Effect of the invention]

As described above, according to the present invention, a video conferencing system can be constructed using a plurality of ISDN audiovisual terminal devices connected to the same ISDN basic interface, so that the line cost of the entire video conferencing system can be reduced. Can be done. Also, since each participant can occupy and use one ISDN audiovisual terminal device, unfavorable situations that occur in the proceedings, such as camera sickness caused by frequent switching of camera angles, etc. Since it is possible to eliminate the unnatural compulsion of a posture for viewing a still image, the usability of the video conferencing system is improved and the effectiveness of the video conferencing system is improved.

[Simple explanation of drawings]

[Figure 1]

The schematic diagram which shows the schematic structure of the video conferencing system which concerns on one Example of this invention.

[Figure 2]

A time chart showing an example of a call control procedure for an ISDN terminal device.

[Fig. 3]

The schematic diagram which shows an example of the signal format of a call setting signal.

[Fig. 4]

The schematic which shows an example of a multi-frame configuration.

[Fig. 5]

The schematic which shows an example of a frame structure.

[Fig. 6]

The schematic diagram which illustrated the signal format of the frame synchronization signal.

[Fig. 7]

The schematic diagram which illustrated the signal format of the bit rate allocation signal.

[Fig. 8]

A time chart for explaining the transmission order of frame data.

[Fig. 9]

A time chart showing a procedure example of TTC Recommendation JT-H.320.

[Fig. 10]

The block diagram which shows the system configuration of the home station which concerns on one Example of this invention.

[Fig. 11]

A timing chart for explaining the switching timing of the transmission signal.

[Fig. 12]

The block diagram which shows an example of the configuration of the master AV terminal device and the slave AV terminal device of FIG.

[Fig. 13]

The block diagram which shows an example of the multiplexing / separation control apparatus of FIG.

[Fig. 14]

A timing diagram for explaining the output timing of the multi-frame number 0 of the transmission signal.

[Fig. 15]

The flowchart which shows the processing example at the time of transmission start of the master AV terminal apparatus.

[Fig. 16]

The flowchart which shows the processing example at the time of transmission start of a slave AV terminal apparatus.

[Fig. 17]

The flowchart which shows the processing example of the terminal switching operation during the data transmission of the master AV terminal device and the slave AV terminal device.

[Fig. 18]

The timing diagram for demonstrating the switching operation of a transmission signal.

[Fig. 19]

The block diagram which shows the structural example of the master AV terminal apparatus which concerns on another Example of this invention.

[Fig. 20]

The block diagram which shows the structural example of the slave AV terminal apparatus which concerns on other Embodiment of this invention.

[Fig. 21]

The block diagram which shows the other Example of the system configuration of the home station which concerns on this invention.

[Fig. 22]

The block diagram which shows the configuration example of the master AV terminal apparatus of FIG.

[Fig. 23]

The block diagram which shows the configuration example of the slave AV terminal apparatus of FIG.

[Fig. 24]

The block diagram which shows still another configuration example of the slave AV terminal apparatus of FIG.

[Fig. 25]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 26]

The schematic diagram which shows an example of the signal format of the command data exchanged over a local area network.

[Fig. 27]

The schematic which shows an example of a command data.

[Fig. 28]

The block diagram which shows the configuration example of the master AV terminal apparatus and the slave AV terminal apparatus shown in FIG.

[Fig. 29]

The flowchart which shows the processing example of the master AV terminal apparatus shown in FIG.

[Fig. 30]

The flowchart which shows the processing example of the slave AV terminal apparatus shown in FIG.

[Fig. 31]

The flowchart which shows the other processing example of the master AV terminal apparatus shown in FIG.

[Fig. 32]

The flowchart which shows the other processing example of the slave AV terminal apparatus shown in FIG.

[Fig. 33]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 34]

The block diagram which shows the configuration example of the master AV terminal apparatus shown in FIG. 33.

[Fig. 35]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 36]

The block diagram which shows the configuration example of the AV terminal apparatus of FIG. 35.

[Fig. 37]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 38]

The block diagram which shows the configuration example of the AV terminal apparatus shown in FIG. 37.

[Fig. 39]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 40]

The block diagram which shows the configuration example of the multiplexing / separation control device of the AV terminal device of FIG. 39.

[Fig. 41]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 42]

The block diagram which shows the configuration example of the master AV terminal apparatus of FIG. 41.

[Fig. 43]

The block diagram which shows the configuration example of the slave AV terminal apparatus of FIG. 41.

[Fig. 44]

The block diagram which shows the other configuration example of the master AV terminal apparatus of FIG. 41.

[Fig. 45]

FIG. 3 is a block diagram showing still another embodiment of the system configuration of the home station according to the present invention.

[Fig. 46]

The schematic diagram which shows the conventional example of the video conferencing system.

[Fig. 47]

The schematic which shows the other conventional example of a video conferencing system.

[Fig. 48]

The schematic diagram which shows the conventional example of the system configuration of the home station of a video conferencing system.

[Explanation of symbols]

MSR, MTR master AV terminal device SLV1 ~ SLVm, SLA1 ~ SLAm Slave AV terminal device 45 Multiplexing / Separation Controller 70 Synchronous control unit 78,88 Delay circuit 87 Delay amount detector LAN local area network 91 Local Area Network Interface Circuit ATE1 ~ ATEm AV terminal device 95 Layer 1/2 controller 96,97 selection circuit 98 Control unit 100,101 Transmission signal synchronization unit 106 Transmission signal selection circuit 107 Signal switch 108 Transmission signal synchronization selection circuit