JP3097016B2 - Communications system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TV conference system, and more particularly to a TV conference system using reservations and ISDN calls.
The present invention relates to a TV conference system that can provide a conference in the same system.

[0002] When a TV conference system is introduced in a corporate network, it is often required to use the TV conference system by reservation operation. There are also requests to use not only the PBX but also the outside line connection with the INS public network, and there is a demand for a TV conference system that can provide these requests by the same system.

[0003]

2. Description of the Related Art As the simplest method of realizing a TV conference operation system using a line reservation, a line reservation system in which a path between terminals is set when an exchange reaches a reservation time has been proposed. In this case, the terminal operates with the dedicated line image.

[0004] In addition to this, if it is desired to simultaneously perform operation using ISDN, the exchange accommodates the terminal by a call control interface including the D channel of ISDN.
In the reserved time zone, a path is established between the terminal and the terminal using the above-mentioned dedicated line image, and in other time periods, a method of enabling operation by ISDN circuit switching by making and receiving a call from the terminal can be considered. .

[0005] Here, H22 of CCITT and TTC
In the case of a design using an ISDN interface, a TV conference terminal conforming to the H.221 and H.242 standards completes a call connection through a call control procedure in accordance with the standardization, and then completes the H.221 and H.24.
It has a procedure of activating two procedures to carry out a TV conference. In the case of a design using a dedicated line interface, the TV conference is conducted by activating the H221 and H242 procedures without using the call control procedure. They differ in that they have procedures.

For this reason, in such a system, the operation of the exchange is performed by a dedicated line or by the ISDN.
It is necessary to switch the mode of the terminal according to whether or not the mode is changed, but the simplest method is to design the terminal to switch the mode by manual operation.

[0007]

However, the operation based on a manual operation requires the operation mode of the leased line terminal and the IS mode.
Switching between the terminal operation modes of the DN is not only complicated but also inconsistent with economic requirements, so a system that can automatically perform such switching is required.

As the simplest means for realizing such a request, a method is conceivable in which the reservation control of the reservation system is directly controlled not only for the exchange but also for the terminal by a separate line. There is a problem that wiring and especially the transmission line of the control line must be secured, which is not always economical.

[0009] The present invention is to solve such a problem of the prior art, and does not complicate the system configuration. Even if the exchange side switches between the dedicated line operation and the ISDN operation, By allowing the mode on the side to automatically follow this, it is possible to use the reservation operation and the outgoing / incoming call operation more economically,
It aims to provide a TV conference system.

[0010]

[Means for Solving the Problems]

(1) FIG. 1 shows the principle configuration of the present invention.
The present invention has a terminal connected via the exchange has a call control function at the interface with the network side, and has a function of transmitting and receiving an in-band signal specific to the terminal service,
In accordance with the control of the reservation management system connected to the exchange, communication is performed by establishing a path between each other in the reserved time zone by using a dedicated line operation, and in other than the reserved time period, establishing a path between each other by the call control operation. In a communication system for performing communication, a terminal recognizes an idle state when a call associated with the terminal does not occur on the call control procedure and does not receive the in-band signal. In the idle state, the terminal continuously searches for the reception of the in-band processing signal specific to the terminal service from the payload signal supplied from the network side, and continues to transmit the in-band signal specific to the terminal service to the payload signal for the network side. Control 101 to identify the reception of an in-band signal specific to the terminal service in the idle state. Automatically recognizes that the terminal has transitioned to the leased line mode state, executes the in-band procedure, establishes communication with the partner device, and automatically activates the terminal service by the leased line procedure operation. In addition to the provision of the dedicated line mode state, when the in-band signal specific to the terminal service is lost for a certain period of time in the leased line mode state, the communication with the partner apparatus is terminated, and the state is shifted to the idle state to recover. Step 102 is performed.

(2) According to the present invention, a terminal connected via an exchange has a call control function at an interface with a network side, and has a function of transmitting and receiving an in-band signal specific to the terminal service. In accordance with the control of the connected reservation management system, communication is performed by establishing a path by using a dedicated line between each other in the reservation time zone, and communication is performed by establishing a path between each other by call control operation in other than the reservation time zone. In the communication system to be performed, the terminal does not generate a call relating to itself in the call control procedure,
And, when the in-band signal is not received, it is recognized as being in the idle state, and in the idle state, the reception of the in-band processing signal specific to the terminal service is searched from the payload signal supplied from the network side. In the idle state, control 101 is performed to continuously transmit an in-band signal specific to the terminal service to the payload signal for the network side. Automatically recognizes that the terminal has transitioned to, and when the connection of the call is completed, the terminal executes the in-band procedure specific to the terminal service and establishes communication with the partner device, thereby automatically performing the call control procedure operation. In addition to providing services, when all calls related to itself are disconnected in the call control mode, communication with the partner device is terminated. To, and controls 103 of the call control mode state to transition to the idle state restoration.

(3) In the case of (1) or (2), the terminal has a call control function continuously even in the leased line mode state.

(4) In any of (1) to (3),
Prioritize the use of the leased line mode and the use of the incoming call according to the terminal setting or its design.When using the terminal with the use of the dedicated line mode, the incoming call in the dedicated line mode is received by the call control procedure. If the terminal is rejected and the terminal is used with priority on incoming calls, the communication with the partner device in the leased line mode is terminated by an incoming call in the leased line mode state, and the terminal switches to the call control mode to make a call with the incoming call. If the communication is established and the terminal setting or its design allows the use of the incoming call when using the dedicated line mode, the incoming call in the dedicated line mode is notified to the user and the user is allowed to select whether or not to respond, If the user selects the call rejection, the call is rejected by the call control procedure.If the user selects the call response, the communication with the partner device in the leased line mode is terminated, and the mode is changed to the call control mode to terminate the incoming call. Establish communication with Prioritize the use of leased line mode and outgoing call according to the terminal setting or its design, and when using the terminal with the use of leased line mode, the outgoing call operation in the leased line mode is disabled and the outgoing call is used. When the terminal is used with priority, the originating operation in the leased line mode state terminates the communication with the partner device in the leased line mode state, transits to the call control mode, and establishes the communication for the outgoing call. .

(5) In any of (1) to (3),
The terminal has a call control function of the interface with the network side is ISD
If the service is provided by the N service, the in-band signal transmitted in the idle state is transmitted to a predetermined time slot from a channel other than the D channel in the layer 1 frame transmitted to the network, and the reception search is performed in the idle state. The in-band signal is searched from all the time slots other than the D channel in the layer 1 frame supplied from the network side, or from a predetermined time slot.

(6) In the case of (5), the exchange establishes an I / O with the terminal.
In the leased line mode, the SDN interface provides the terminal with communication data corresponding to the transfer rate from the predetermined time slot out of all the time slots other than the D channel in the layer 1 frame.

(7) In the case of (5), a time slot determined in advance from all time slots other than the D channel in the layer 1 frame is defined as a first time slot, and call control communication and dedicated line communication are performed. Provide coexistence.

(8) In the case of (5), the transfer rate is assigned to all time slot data other than the D channel.

(9) T in any of (1) to (8)
In a V-conference system, a terminal uses a CCITT, TTC standard H21 as an in-band signal specific to a terminal service.
1, H242 is adopted.

(10) In the TV conference system in any one of (1) to (9), the exchange and its reservation management system or the external control device are sometimes called by the user network interface having a call control procedure. After executing the control procedure, a path is established for the terminals. In some cases, a path is established between the terminals without executing the call control procedure by automatic control or manual operation from the reservation system.

[0020]

The terminal in the TV conference system of the present invention performs the following operation. (1) The terminal of the TV conference system according to the present invention has a call control function at an interface with the network side, has a function of transmitting and receiving an in-band signal specific to the terminal service, and has its own function in the call control procedure. A state where it is recognized that the relevant call has not occurred and that the in-band signal has not been received,
It recognizes that the terminal is idle (empty).

(2) If a call related to the terminal itself occurs in the idle state, the terminal automatically recognizes that it has transitioned to the call control mode state of the terminal. The terminal service is automatically provided by the operation of the call control procedure by establishing the communication with the partner apparatus by executing the in-band procedure.

(3) In the call control mode, if all of the calls related to itself are disconnected, the communication with the partner device is terminated, and the system shifts to the idle state to recover.

(4) At least in the idle state, the mobile station continues to search the payload signal supplied from the network side for reception of an in-band processing signal specific to the terminal service. (5) At least in an idle state, an in-band signal specific to the terminal service is continuously transmitted as a payload signal to the network side. (6) In the idle state, if the reception of the in-band signal specific to the terminal service is identified, the terminal automatically recognizes that the terminal has transitioned to the leased line mode state, executes the in-band procedure, and executes the other device. By establishing communication with the terminal, the terminal service is automatically provided by the leased line procedure operation.

(7) In the leased line mode state, if the in-band signal peculiar to the terminal service has disappeared for a certain period of time, the communication with the partner apparatus is terminated, and the apparatus transitions to the idle state to recover. (8) It has a call control function continuously even in the leased line mode.

(9) Prioritizing the use of the dedicated line mode and the use of the incoming call are performed according to the terminal setting or its design. If the terminal is used with the exclusive use of the dedicated line mode, the incoming call in the dedicated line mode state is not received. , Reject the incoming call according to the call control procedure, and if the terminal is used with priority on the use of incoming call,
By the incoming call in the leased line mode state, the communication with the partner device in the leased line mode state is terminated, and a transition is made to the call control mode to attempt to establish the communication with the incoming call according to the above item (2).

(10) If the incoming call can be used when using the leased line mode according to the terminal setting or its design, if there is an incoming call in the leased line mode, the incoming call is notified to the user to determine whether or not a response is possible. Call, if the user selects rejection, reject the call by the call control procedure,
If the user selects the incoming call response, the communication with the partner device in the leased line mode is terminated, the mode is shifted to the call control mode, and the communication with the incoming call is to be established according to the above item (2).

(11) Prioritizing the use of the dedicated line mode and the use of the outgoing call are performed by setting or designing the terminal, and if the terminal is used in accordance with the use of the dedicated line mode, the outgoing call is made in the dedicated line mode. Operation is invalid,
If the terminal is to be used with the priority of outgoing call use, the outgoing call operation in the leased line mode terminates the communication with the partner device in the leased line mode, transits to the call control mode, and returns to the above item (2). In accordance with the outgoing call.

(12) If the call control function of the interface with the network side is based on the ISDN service,
The in-band signal to be transmitted according to the paragraph (5) is transmitted to a predetermined time slot (TS) from a channel other than the D channel in the layer 1 frame transmitted to the network side.

(13) If the call control function of the interface with the network side is based on the ISDN service, the search for the in-band signal according to the above item (4) is performed in the layer 1 frame supplied from the network side. From all the time slots other than the D channel or from the same predetermined time slot as in the paragraph (12).

The exchange in the TV conference system of the present invention operates as follows. (14) Due to the ISDN interface with the terminal, in the leased line mode, communication data corresponding to the transfer rate is provided to the terminal from the time slot predetermined in accordance with the paragraphs (12) and (13).

The communication system in the TV conference system according to the present invention operates as follows. (15) The time slot determined in advance by the above (12), (13), and (14) is defined as the first time slot, and the call control communication and the dedicated line communication coexist and are provided.

The TV conference terminal or the AV terminal according to the present invention operates as follows. (16) Adopting CCITT and TTC standard H221 and H242 as the in-band signals specific to the terminal services described in the above (1) to (14), and automatically selecting a call control procedure and a dedicated line procedure. I do.

The exchange according to the present invention and its reservation management system or external control device operate as follows. (17) A certain user network interface having a call control procedure executes the call control procedure in some cases, establishes a path to the terminal, and in some cases executes the call control procedure by automatic control or manual operation from the reservation system. Do not execute, establish a path between terminals.

The dedicated line reservation TV conference system according to the present invention operates as follows. (18) Having the functions described in the above (1) to (17),
With TV conference terminal, exchange and reservation management system,
In addition to reservation operation on a dedicated line, ISDN call operation can be freely performed. (19) In the system of the above item (18), the transfer rate is allocated to all the time slot data other than the D channel according to the above item (14).

FIGS. 1 to 4 respectively show T and T in the present invention.
1 shows the flow of the principle of a V conference terminal, (1) to (4). FIG. 1 shows the overall flow, and FIGS. 2 to 4 show control of an idle state, control of a dedicated line mode state, and call control, respectively. 4 shows a flow of control in a control mode state. Hereinafter, the operation of the TV conference terminal according to the present invention will be described with reference to these drawings.

First, the terminal, in its idle state,
As previously described in paragraphs (1), (4), (5), (8), (12), (13), (15), and (16), a predetermined H221 is added to the time slot on the user network interface
The frame is transmitted, and the receiving side performs synchronization search in this time slot.

Here, if the H221 frame synchronization is established on the receiving side, the mode is changed to the dedicated line mode as described in the above item (6), and communication with the partner terminal is established in accordance with the H242 procedure.

Also, if in this idle state, ISD
When an N-call or ISDN call operation is performed, a call connection is made by the D-channel protocol, and a transition is made to the call control mode (ISDN mode) as described in (2) above.
At the same time, an H221 frame is transmitted in a time slot determined for each call with the exchange, and a synchronization search is performed in this time slot on the receiving side.
The communication with the partner terminal is established according to the 42 procedure.

In any of the communication states of the modes, when it is recognized that the communication has been completed as described in the above items (3) and (7), the current communication mode is initialized and the communication mode is set to the idle state. Recover.

[0040]

FIG. 5 shows a configuration of an embodiment of a TV conference system according to the present invention.
Reference numerals 3 and 4 denote terminals of the branch offices 1 and 2, respectively, and reference numeral 5 denotes a branch terminal. 6 is a subscriber line termination device (DS
U) and 7 are the subscriber line termination units (DSUs) of branch 2 and 8,
9 is a subscriber line termination unit (DSU) corresponding to each of the branch offices 1 and 2 of the head office, 10 is a PBX provided in the head office,
Reference numeral 11 denotes a reservation management system provided in the PBX 10.

At the head office, terminal 1, terminal 2 and PBX 1
0 are connected via extension 1 and extension 2, respectively.
SU8, DSU9 and PBX10 have extensions 3,
It is connected via extension 4. In addition, DSU8 of the head office
The DSU 6 of the branch 1 and the DSU 9 of the head office and the DSU 7 of the branch 2 are respectively connected via dedicated lines. Further, the PBX 10 at the head office and the terminal 5 at the branch office are connected via an INS network from an outside line of the head office.

In FIG. 5, terminals 1 to 4 are TV conference terminals to which the present invention is applied, and terminal 5 may be a TV conference terminal supporting only the ISDN function. The same TV conference terminal may be used. PBX
Reference numeral 10 denotes an exchange having functions as described in (14), (15) and (17) described in the section of operation. The reservation management system 11 is an external control device of the PBX 10 having a function as shown in (17) described in the section of operation.

Extensions 1 to 4 of the PBX 10 are interfaces having a physical speed of 1.544 Mbps according to, for example, the I431 standard, which provide a terminal with an ISDN primary circuit switching service having a D channel in the TS 24. It is. Further, DSU6 to DSU9 are also terminating devices for a leased line having a similar user network interface.

In such a system configuration, as shown in (14) and (15) described in the section of operation, for example, the transfer speed is 384 Kbps (hereinafter referred to as H0), the first time slot is TS1, and Determine it.

For example, here, from 13:00 to 15:00, terminals 1 to
A path is set up between the terminals 4. At 13:00, under the control of the reservation management system 11, the PBX 10 sets a communication path of H0 between the extension 1 to the extension 4, and at this time, TS1 to TS6 are set at the respective extension interfaces as described above. Shall be used.

If the power is turned on, the terminal 1 and the terminal 4 transmit the H221 frame starting from the previously determined TS1 as described above, and on the receiving side,
By performing the synchronization search, the state mutually transits to the H221 synchronization establishment state. Then, according to the H242 procedure, both capacity exchange procedures are performed, the communication mode is determined,
The communication state becomes the dedicated line mode of the TV conference.

On the other hand, if the power is turned on, the terminal 2 and the terminal 4 perform the transmission of the H221 frame and the reception synchronization search similarly to the terminal 1 and the terminal 4, but the PBX 10 must set the communication path. If it is, it is waiting in this idle state.

Here, for example, if the terminal 2 performs a call operation to the terminal 3 by H0, the terminal 2 transmits a call message to the PBX 10 using the D channel. At this time, the PBX 10 transmits an incoming call message to the D channel of the terminal 3 if a time slot corresponding to H0 can be secured in the extension 2, the extension 3 and the PBX by the ISDN circuit switching service.

Terminal 3 waiting in the idle state receives this incoming call message, transmits a response message to PBX 10 via the D channel, transitions to the ISDN mode state, and completes the call connection. State and the PBX 10 sends this response message to the calling terminal 2.
, The terminal 2 also enters the call connection completed state in the ISDN mode state.

At this time, in each extension interface (extension 2 and extension 3), according to the D channel protocol, a time slot corresponding to H0 to be used, TS =
TS (y) to TS (y + m-1) are determined. Here, for example, it is assumed that TS7 to TS12 are determined for both. Here, m is the transfer speed, and is 6 in the case of H0.

Here, both terminals (terminal 2, terminal 3)
Is already in the ISDN mode, so the H221 frame transmission and reception synchronization search in the idle state are:
The H221 has been temporarily stopped and newly used in H221 using TS7 to TS12 determined according to the D channel protocol.
After resuming frame transmission and reception synchronization search, synchronization is established with each other. According to the H242 procedure, both capacity exchange procedures are performed, and the communication mode is determined.
The state becomes the ISDN mode communication state of the V conference.

For the communication between the terminals 1 and 4 again, for example, when the reservation end time comes, the PBX 10 controls the extension 1
Release the H0 communication path between them. At this time, the terminal 1 and the terminal 4 initialize the current communication mode by detecting out-of-synchronization of the H221 frame for a fixed time (for example, 1 second) as described in (7) in the section of the operation. Then, after terminating the communication and transiting to the idle state again, the transmission and reception synchronization search of the H221 frame with TS1 at the head is resumed and waits. Thereafter, when the reserved time comes again, the same dedicated line mode communication operation is started, and when the time is outside the reserved time, the same ISDN mode communication by the incoming and outgoing call as the terminal 2 and the terminal 3 is also possible.

For the communication between the terminal 2 and the terminal 3 again, for example, if a disconnection operation from the terminal 2 transfers a disconnection message to the PBX 10 via the D channel of the extension 2, the PBX 10 follows the D channel protocol. By disconnecting the time slot and simultaneously transmitting a disconnection message to the terminal 3, the communication path between the terminal 2 and the terminal 3 is released, and the interface of the extension 2 and the extension 3 is in a release completed state. Will be disconnected and restored

As a result of the disconnection restoration, the terminal 2 and the terminal 3
The H221 that initializes the current communication mode, terminates the communication, transitions to the idle state again as shown in the section (3) described in the section of the operation, and sets the
Resume frame transmission and reception synchronization search and wait. In the subsequent operation, as in the operation of the terminal 1 or the terminal 4 described above, the dedicated line mode communication operation is started when the reserved time comes, and the ISDN mode communication by outgoing / incoming call is also possible outside the reserved time. is there.

FIGS. 6 to 8 are diagrams (1/3) to (3/3) showing examples of the state transition of the TV conference terminal according to the present invention, wherein the priority order = (ISDN call> (dedicated line mode)). , IS
DN incoming call))). 6 to 8
, The state is an idle state, the state and are in the leased line mode state, and the state is
This is the N mode state. The remarks for each figure are as follows.

(1) TS is a time slot on the user network interface. (2) y to y + m-1 of the TS are time slot numbers determined for each call by the Dch protocol, and m is the information transfer speed. (3) Simultaneously with turning on the power, the transmission / reception TS is set to 1 to n, H221 frame transmission / reception search is started, and a transition is made to a state. (4) 1 to n are time slot numbers in the leased line mode determined in advance with the exchange, and n is the information transfer speed.

FIG. 9 and FIG. 10 show D in the TV conference terminal.
FIGS. 6A and 6B show state transition examples of an ISDN call control procedure according to a channel protocol, and FIGS.
9 illustrates an example of a state transition of a part related to ISDN call control in FIG. 8. The remarks for each figure are as follows. (1) Underlined content is recognized by the terminal. (2) SET-UP msg is an outgoing or incoming message. CONN msg is a response message. DISC m
sg is a disconnection message. 9 and 10 show only the processing necessary for explaining the present invention.

First, the terminal sets the transmission / reception time slots to 1 to n at the same time as the power is turned on, starts transmission of the H221 frame and search for reception, and transitions to the state. When the H221 frame synchronization is established in the state, the T1 timer (for example, 10 seconds) is set, the H242 standard capacity exchange procedure is started, and the state transits to the state.

In the state, if the H242 standard capability exchange procedure is completed before the T1 timer expires, T1
The timer is stopped normally, the communication mode is set within the range of the partner capability, the state is transited, and the TV conference communication is started. If the T1 timer expires, the T1 timer is set again and the capability exchange procedure is retried.

In states and states, if H2
When the out-of-synchronization of 21 frames is detected for a certain period of time (for example, 1 second), a process d shown in FIG.

Next, in the state, when the ISDN call operation is performed, the state transition related to the call control is, as shown in FIG. 9, a SET-UP (call setting) msg indicating a call (or an incoming call). (Message) from U0 to U1
To CALL-PROC (call setting acceptance)
If a message is received, the flow goes to U3. At this time, the terminal indicates the used time slot from the exchange by the CALL PROC message, and the TS (y) to TS (y)
(Y + m-1) is recognized. In U3, if the partner terminal responds to the incoming call, it receives a CONN (response) message, transmits a CONN-ACK (response confirmation) message, transits to U10, and recognizes that the call connection has been completed.

When recognizing the call connection completion state, it executes the process a shown in FIG. 7 and transits to the state. In the state, before the T1 timer expires, if the H221 frame synchronization is established, the H242 standard capacity exchange procedure is started and transition is made to the state, and if the capacity exchange procedure is completed before the T1 timer expires, the T1 timer is expired. Is stopped normally, the communication mode is set within the range of the partner capability, the state is transited, and the TV conference communication is started.

If state, state, T
If one timer expires or if H221 frame out-of-synchronization is detected for a certain period of time (for example, one second), retry processing can be performed. In this case, processing b is executed and the state transitions to the state. I have.

Thereafter, when the ISDN partner disconnection or the self disconnection operation is performed in the state, when the DISC (disconnection) message is received or the disconnection operation is performed in the U10 state shown in FIG. The state transits to U0, executes the processing c shown in FIG. 8, and transits to the state.

In the state, if an ISDN call arrives, the state transitions to U6 since the SET-UP message is received in the state U0 in FIG. 9, and a response request is generated by a user operation or automatically, and the CONN message is generated. Is transmitted, and the process transits to U8. After confirming the reception of the CONN-ACK message, the process transits to U10 and recognizes the completion of the call connection. The time slot TS to be used
(Y) to TS (y + m-1) are displayed from the exchange when the SET-UP message is received, and are stored.

When recognizing the call connection completion state, the processing e shown in FIG. 7 is performed, and the state transits to the state.
N. The state transitions through the same process
Start conference communication.

Next, the conflict between the leased line mode and the use of ISDN will be described. As shown in (8) of the above-mentioned operation section, in the states of FIGS. 6 to 8 as well, since the D-channel processing is continued, the state transitions shown in FIGS. If no has occurred, state U0
Waiting at.

Here, in the present embodiment, the above-described operation section
As an example of (9) to (11), an ISDN call has the highest priority, and a terminal under which an ISDN call and a leased line mode can be used in parallel is reflected in the state transition diagrams of FIGS. 9 and 10. . This is because, in the states and states shown in FIGS. 6 to 8, an ISDN call can be made, and for an ISDN incoming call, a method of notifying the user of the incoming call and selecting whether to answer or not, or terminal setting Automatically reject or respond.

For example, when the state and the state are automatically rejected, the SET in the state U0 in FIG.
-Transit to U6 upon receipt of UP message, but automatically generate disconnection request, REL-COMP (release complete)
This is executed by making a transition to U0 after transmitting the message. Note that the subsequent procedures when the incoming call is answered and the ISDN call is made are the same state transition as the procedure in the state.

Here, (1) in the above operation section
As shown in 9), for example, in the 1.544 Mbps extension interface of the present embodiment, in the system in which the time slots of the extension interface secured by the PBX 10 by the reservation control from the reservation management system 11 are TS1 to TS23, When the terminal in the example is operated, an ISDN incoming / outgoing call during a reservation conference automatically becomes a time slot busy and can be prohibited.

That is, if a call is made to a terminal that is in a reservation conference, all the TSs of the extension interface are in use according to the Q931 standard, so the PBX 10 sends a SET-UP message to the destination terminal. Without transmitting, the calling terminal is notified of the calling failure. This means that the calling terminal receives the DISC (disconnect) message in the U3 state shown in FIG.
This is carried out by transmitting the message and transiting to U19, and then receiving the REL-COMP message and transiting to U0.

Also, when a terminal in a reservation conference makes a call, the PBX 10 similarly issues a SET-UP to the destination terminal because all the time slots are already in use by the extension interface of the calling terminal. Without transmitting the message, the calling terminal is notified of the call failure. This is performed by the process of receiving the REL-COMP message and transitioning to the U0 state in the U1 state shown in FIG. 10 at the calling terminal.

FIG. 11 shows a configuration example of a TV conference terminal. This configuration is exactly the same as the configuration example of a general TV conference terminal that supports only the ISDN, and the present invention can be realized only by changing the control software of the TV conference terminal. Also, FIG.
This shows the configuration of one frame, in which F indicates a frame bit and TS24 is a D channel.

In FIG. 11, an I431 reception / synchronization separation section 21 terminates an I431 frame from the PBX or DSU to perform decoding of a B8ZS code and synchronization separation, and performs layer 2 processing of ISDN layer 2. The D channel is separated into the processing unit 30, and the frame pulse is passed to the reception-side effective CLK generation unit 25. Receiving-side valid CLK generator 2
5 is an effective T based on the effective TS control from the CPU 31.
The clock corresponding to S is passed to the H221 synchronization separation unit 23.

The H221 sync separation unit 23 reads the received data for the valid TS, synchronizes the H221 frame,
The BAS code in the H221 frame is notified to the CPU 31, and the speech code and the image code are appropriately separated under the control of the CPU 31. Voice DECODER 27 and H
The H.261 standard image CODEC 29 decodes audio and images under the control of the CPU 31.

Also, the audio coders 28 and H261
Under the control of the CPU 31, the standard image CODEC 29 performs audio input and image input encoding processing, and passes the encoded data to the H221 multiplexing unit 24. The H221 multiplexing unit 24 controls the H221
It multiplexes frames and inserts transmission BAS codes.

The transmission-side effective CLK generation unit 26
By the effective TS control from 1, a clock corresponding to the effective TS is passed to the H221 multiplexing unit 24 and a frame pulse is passed to the I431 multiplexing / transmission unit 22. I
The 431 multiplexing / transmission unit 22 transmits the transmission data and the transmission D
The channel is multiplexed into an I431 frame, subjected to B8ZS encoding, and transmitted.

The H242 standard capacity exchange procedure and mode setting are controlled by the CPU 31 according to H221.
This is carried out with the partner terminal via the BAS code in the frame.

[0079]

As described above, according to the present invention, switching between the leased line mode and the ISDN mode can be performed automatically following the mode of the exchange without relying on manual operation. It is possible to provide a TV conference terminal capable of providing a TV conference by using the same system for reservation use and ISDN incoming / outgoing call use.

The TV conference terminal according to the present invention uses the conventional IS
Since it can be realized only by changing the control software without changing the hardware configuration of the DN-compatible TV conference terminal, there is an advantage that it can be realized easily and economically.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle flow (1) of a TV conference terminal according to the present invention.

FIG. 2 is a diagram showing a principle flow (2) of the TV conference terminal according to the present invention.

FIG. 3 is a diagram showing a principle flow (3) of the TV conference terminal according to the present invention.

FIG. 4 is a diagram showing a principle flow (4) of the TV conference terminal according to the present invention.

FIG. 5 is a diagram showing a configuration of a TV conference system according to an embodiment of the present invention.

FIG. 6 is a diagram (1/3) showing an example of state transition of a TV conference terminal according to the present invention;

FIG. 7 is a diagram (2/2) showing a state transition example of the TV conference terminal according to the present invention;

FIG. 8 is a diagram (3/3) showing an example of state transition of the TV conference terminal according to the present invention.

FIG. 9 is a diagram showing an example of state transition of an ISDN call control procedure according to a D channel protocol in a TV conference terminal (1/1);
2).

FIG. 10 is a diagram showing an example of a state transition of an ISDN call control procedure according to a D channel protocol in a TV conference terminal (2 /
2).

FIG. 11 is a diagram illustrating a configuration example of a TV conference terminal.

FIG. 12 is a diagram illustrating a configuration of an I431 frame.

[Explanation of symbols]

 101 Control of idle state 102 Control of leased line mode state 103 Control of call control mode state

Claims (10)

(57) [Claims] A terminal connected via an exchange has a call control function at an interface with a network side, has a function of transmitting and receiving an in-band signal specific to the terminal service, and has a reservation connected to the exchange. A communication system in which communication is performed by establishing a path between each other in a reserved time zone based on the control of the management system by using a dedicated line, and in other than the reserved time period, communication is performed by establishing a path between each other by a call control operation. In the above, the terminal recognizes that the terminal concerned is in an idle state when no call associated with the terminal occurs in the call control procedure and does not receive the in-band signal. While continuing to search for the reception of in-band processing signals specific to the terminal service from the supplied payload signals, The signal, the control idle continue to send its terminal service-specific in-band signals (10
Performing 1), in the idle state, when the reception of the in-band signal specific to the terminal service is identified, the terminal automatically recognizes that the terminal has transitioned to the leased line mode state, executes the in-band procedure, and By establishing communication with the device, the terminal service is automatically provided by the leased line procedure operation, and when the in-band signal specific to the terminal service is lost in the leased line mode for a certain period of time, the partner A communication system characterized by performing control (102) of a leased line mode state for terminating communication with a device, transiting to an idle state, and restoring. 2. A terminal connected via an exchange has a call control function at an interface with a network side, has an in-band signal transmission / reception function specific to the terminal service, and has a reservation connected to the exchange. A communication system in which communication is performed by establishing a path between each other in a reserved time zone based on the control of the management system by using a dedicated line, and in other than the reserved time period, communication is performed by establishing a path between each other by a call control operation. In the above, the terminal recognizes that the terminal concerned is in an idle state when no call associated with the terminal occurs in the call control procedure and does not receive the in-band signal. While continuing to search for the reception of in-band processing signals specific to the terminal service from the supplied payload signals, The signal, the control idle continue to send its terminal service-specific in-band signals (10
1) is performed, and in the idle state, when a call related to the terminal itself occurs, the terminal automatically recognizes that the terminal has transitioned to the call control mode state, and when the call connection is completed, the in-band specific to the terminal service. By performing the procedure and establishing communication with the partner device, automatically providing the terminal service by the call control procedure operation, and in the call control mode state, when all of the calls related thereto are disconnected, A communication system characterized by performing control (103) of a call control mode state for terminating communication with a partner apparatus, transiting to an idle state, and restoring. 3. The communication system according to claim 1, wherein the terminal has a call control function continuously even in a leased line mode state. 4. The communication system according to claim 1, wherein priorities are assigned to the use of the dedicated line mode and the use of the incoming call according to the terminal setting or the design thereof, and the terminal is assigned priority in the use of the dedicated line mode. When using, the incoming call in the leased line mode state is rejected by the call control procedure. Terminates communication with the partner device, transitions to the call control mode, establishes communication with the incoming call, and if the terminal setting or its design allows the use of incoming calls when using the dedicated line mode, the dedicated line mode Incoming calls in the state, notify this to the user and select whether to answer,
When the user selects the call rejection, the call is rejected by the call control procedure.When the user selects the call response, the communication with the partner device in the leased line mode is terminated, and the mode is changed to the call control mode to receive the call. Establish communication with the call, prioritize the use of leased line mode and outgoing call by terminal setting or its design. When the terminal is used with outgoing call priority, the call operation in the leased line mode state terminates the communication with the partner device in the leased line mode state, and transitions to the call control mode to place the call. A communication system for establishing communication by a call. 5. The in-band communication system according to claim 1, wherein the terminal transmits in the idle state if a call control function of an interface with the network side is based on an ISDN service. A signal is transmitted from a channel other than the D channel to a predetermined time slot in a layer 1 frame transmitted to the network side, and an in-band signal to be received and searched in an idle state is transmitted in a layer 1 frame supplied from the network side. A communication system for searching from all the time slots other than the D channel or from a predetermined time slot. 6. The communication system according to claim 5, wherein the exchange uses the ISDN interface with the terminal to set a predetermined time slot from all time slots other than the D channel in the layer 1 frame in the leased line mode. A communication system characterized in that the communication data is provided to the terminal at the transfer speed at the head. 7. The communication system according to claim 5, wherein a time slot determined in advance from all time slots other than the D channel in the layer 1 frame is defined as a first time slot, and call control communication and a dedicated line are performed. A communication system characterized by providing communication and coexistence. 8. The communication system according to claim 5, wherein a transfer rate is assigned to all time slot data other than the D channel. 9. The communication system according to claim 1, wherein the terminal uses a CCITT, TTC standard H211, as an in-band signal specific to the terminal service.
A TV conference system employing H242. 10. The communication system according to claim 1 or the video conference system according to claim 9,
The exchange and its reservation management system or external control device execute the call control procedure once and extend the path to the terminal by the user network interface having the call control procedure, and in some cases automatic control from the reservation system A TV conference system wherein a path between terminals is established without executing a call control procedure by manual operation.