JPH07203064A - Call connection control method - Google Patents

Abstract

PURPOSE:To perform the call connection control without deteriorating the circuit application efficiency when the sub-channel multiplex communication is carried out among plural terminals. CONSTITUTION:A telephone system 11 makes an out-bound call to a telephone system 12 and answers the system 12. Thus a channel 21 is connected between both systems 11 and 12. Then the calling system 11 sends a prescribed specific bit pattern to the selected one of sub-channels 22 and 23 included in the channel 21. The system 12 detects the specific bit pattern of the system 11 and switches the selected sub-channel to a control mode. Then the system 11 sends the connection control information via the sub-channel switched to the control mode. The system 12 switches the sub-channel to a communication mode based on the received connection control information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call connection control method, and more particularly, to a communication for dividing a channel connected to a digital communication network into a plurality of sub-channels and performing multiplex communication between a plurality of terminals. The present invention relates to a method of controlling a connection state of subchannels between terminals in a system.

[0002]

2. Description of the Related Art Currently, as a public digital communication network,
So-called ISDN is in service. The basic interface of ISDN consists of two 64 kbps B channels and one 16 kbps D channel. Voice calls and user data are transmitted using the in-band, that is, the B channel, and control information is transmitted using the out-band, that is, the D channel.

By the way, it is conceivable to improve the utilization efficiency of a line by dividing one B channel into a plurality of sub-channels and multiplexing them, encoding voice at a low bit rate and transmitting it in sub-channel units. ing. In such a sub-channel transmission system, a plurality of audio signals can be simultaneously transferred using one B channel.

Conventionally, as a sub-rate connection method using sub-channel multiplexing, a method of fixedly allocating one sub-channel for transmission of connection control information (Information and Communication Research Society, Communication Method Research Group, CS89-23) and , PB signals (push button signals) corresponding to call control signals are transferred in-band (that is, in the B channel) ("Sharp technique", Vol. 53, pp. 11-16).

It should be noted that none of the above-mentioned prior arts mentions only the multiplex communication between two stations, and does not provide the function of performing the detour relay connection to another terminal via the multiplex-connected terminal.

[0006]

In the former conventional example, one sub-channel is fixedly assigned for transmission of connection control information, so that the sub-channel is used for a call or data communication. However, there was a problem in that the utilization efficiency of the line decreased.

On the other hand, in the latter conventional example in which the connection control information is transferred using the PB signal, the start of the connection or disconnection can be notified by defining and transferring the PB signal of connection or disconnection. There is a problem that complicated connection control such as detour connection cannot be performed because more information cannot be sent.

Therefore, an object of the present invention is to provide a call connection control method capable of performing subchannel connection control without degrading the line utilization efficiency when subchannel multiplex communication is performed between a plurality of terminals. is there. Another object of the present invention is to provide a call connection control method capable of realizing detour relay communication using subchannels.

[0009]

The invention according to claim 1 is
In a communication system in which a channel connected to a digital communication network is divided into a plurality of sub-channels and multiplex communication is performed between a plurality of terminals, a method of controlling a connection state of the sub-channels between the terminals is provided. A first step of switching an arbitrary subchannel selected from the channels to a control mode, and a second step of transferring connection control information necessary for connection control of the subchannel via the subchannel switched to the control mode And the third step of controlling the connection state of the sub-channel to which the connection control information is transferred, based on the transferred connection control information.

According to a second aspect of the present invention, in the first aspect of the invention, the second step is to constantly monitor the data transferred on each sub-channel, and detect the data having a predetermined specific bit pattern. When it is detected, the subchannel to which the data is transferred is switched to the control mode.

According to a third aspect of the present invention, in the first aspect of the invention, the third step is to switch to the communication mode after performing a predetermined connection process on the sub-channels switched to the control mode. Characterize.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the communication system has a bypass relay connection function.
When the above-described terminal is provided and the detour relay communication is performed between the first terminal and the third terminal using the second terminal as a relay terminal, the first and second steps are performed with the first terminal. After connecting between the second terminals and between the second terminal and the third terminal by the sub-channels switched to the control mode, the connection control information is transmitted using the sub-channels switched to the control mode. The sub-channels are sequentially transferred from the first terminal to the second and third terminals, and the third step is to switch the control processing for the detour relay connection to the control mode based on the transferred connection control information. After performing the above, each of the sub-channels is switched to the communication mode.

The invention according to claim 5 divides a channel connected to a digital communication network into a plurality of sub-channels,
In a communication system that performs multiplex communication between multiple terminals,
The first slave unit registered in the first terminal and the first slave unit registered in the third terminal via the first, second, and third terminals each having the bypass relay connection function. A method for performing bypass relay communication with a second child device, wherein the first terminal is configured such that the address of the second child device registered in the third terminal, which is the destination address, is set as the sub-address. Forwarded call setup message to the second terminal through the out-band of the digital communication network, and the second terminal receives the first sub-address based on the sub-address set in the call setup message received from the first terminal. It is characterized in that sub-channel connection control is executed with the third terminal.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the second terminal is such that the subaddress set in the received call setting message is not the address of the slave unit registered in the own terminal. , A terminal in which a slave unit indicated by the sub-address is registered is searched, and a call setting message is transferred to the searched terminal.

The invention according to claim 7 divides a channel connected to a digital communication network into a plurality of sub-channels,
In a communication system that performs multiplex communication between multiple terminals,
Communication is performed between the first slave unit registered in the first terminal and the second slave unit registered in the second terminal via the first and second terminals. Method, first
Of the second terminal through the outband of the digital communication network to the second terminal via the outband of the digital communication network, the call setting message in which the address of the second handset registered in the second terminal which is the destination address is set as the subaddress. The transfer is performed, and the second terminal executes connection control with the second handset based on the sub-address set in the call setting message received from the first terminal.

[0016]

In the invention according to claim 1, any subchannel selected from the plurality of subchannels is switched to the control mode, and the connection control information is transferred via the subchannel switched to this control mode. Based on the transferred connection control information, the connection state of the sub-channel to which the connection control information is transferred is controlled. As described above, according to the first aspect of the present invention, since the connection control information is transferred via the sub-channel subject to the connection control, the specific sub-channel is dedicated to the connection control information as in the conventional case. Without subchannel connection control. Therefore, all the sub-channels can be used for communication, and the line utilization efficiency can be improved.

According to the second aspect of the present invention, the data transferred on each sub-channel is constantly monitored, and when the data having a predetermined specific bit pattern is detected, the sub-channel to which the data is transferred is selected. Since the control mode is switched to, it is possible to smoothly shift to the control mode without causing confusion with the communication data even if the sub-channel is being used for communication.

According to the third aspect of the invention, the sub-channel switched to the control mode is subjected to a predetermined connection process and then switched to the communication mode.

In the invention according to claim 4, when the bypass relay communication is performed between the first terminal and the third terminal using the second terminal as a relay terminal, the first terminal and the second terminal are connected. while,
After connecting between the second terminal and the third terminal by the subchannels switched to the control mode, the connection control information is transferred from the first terminal to the second terminal by using the subchannels switched to the control mode. Transfer to the third terminal sequentially,
Based on the transferred connection control information, the control process for the bypass relay connection is performed on each sub-channel that has switched to the control mode, and then each sub-channel is switched to the communication mode. Therefore, the bypass relay communication using the sub-channel multiplex communication can be realized without lowering the line utilization efficiency.

In the invention according to claim 5, the first slave unit registered in the first terminal and the third slave terminal are registered via the first, second and third terminals. When performing detour relay communication with the second handset that has been set up, the call setup message in which the address of the second handset registered in the third terminal, which is the destination address, is set as the sub address is displayed. , From the first terminal to the second terminal via the out-band of the digital communication network. Then, the second terminal executes sub-channel connection control with the third terminal based on the sub-address set in the call setup message received from the first terminal. in this way,
According to the invention of claim 5, even when communication is not performed between the first terminal and the second terminal, the second terminal is used as a relay terminal without providing a special procedure using in-band communication. As a result, the bypass relay communication using the sub-channel can be performed between the first slave unit and the second slave unit.

In the invention according to claim 6, when the subaddress set in the received call setting message is not the address of the child device registered in the own terminal, the second terminal indicates the child indicated by the subaddress. The terminal that the machine is registered is searched, and the call setup message is transferred to the searched terminal.

In the invention according to claim 7, via the first and second terminals, the first slave unit registered in the first terminal and the second slave terminal registered in the second terminal are registered. Second
When communicating with the slave unit of the digital communication network, a call setup message in which the address of the second slave unit registered in the second terminal, which is the destination address, is set as the sub address is sent to the outband of the digital communication network. Via the first terminal to the second terminal. Then, the second terminal executes the connection control with the second handset based on the subaddress set in the call setting message received from the first terminal.

[0023]

First Embodiment FIG. 1 shows a connection control per subchannel in a telephone device (an example of a terminal) in a communication system for realizing a call connection control method according to a first embodiment of the present invention. FIG. 3 is a schematic block diagram showing the configuration of a sub-channel control unit that performs In FIG. 1, a sub-channel control unit 7 includes a demultiplexing unit 1 that divides a channel connected to a digital communication network into sub-channels, and data that has a specific bit pattern by constantly monitoring data transferred for each sub-channel. Pattern detection unit 2, a channel mode control unit 3 that receives notification from the pattern detection unit 2 to control switching of channel modes, and an instruction from the channel mode control unit 3 to specify a subchannel connection destination. Channel switching unit 4
A connection control processing unit 5 that performs sub-channel connection control processing, and a call processing unit 6 that performs data processing during communication. The telephone device also has a sub-channel control unit having the same configuration as in FIG. 1 for other sub-channels. It is multiplexed with the sub-channel controller and one I
Corresponds to the SDN line.

FIG. 2 is a schematic diagram showing an example of the connection state of the telephone device in the communication system which realizes the first embodiment of the present invention. Hereinafter, referring to FIG. 1 and FIG.
The call connection control operation in the first embodiment of the present invention will be described.

(1) Operation when Channel is Connected First, the operation when the channel 21 is connected in the state where communication is not performed between the telephone device 11 and the telephone device 12 shown in FIG. 2 will be described. For example, if the telephone device 11 is the calling side, the telephone device 11 first calls the telephone device 12,
When the telephone device 12 responds, the telephone device 11-the telephone device 1
The channel 21 is connected between the two. At this time, control information is sent from the telephone device 11 to the telephone device 12 out-of-band (that is, D channel), and the connection control of the channel 21 is executed based on this control information. The connection control at this time is the same as that of the conventional ISDN. Therefore, when the telephone device 12 does not respond, the channel 21 is not connected and the billing is not performed.

(2) Operation when sub-channel is connected After the channel 21 is connected, the telephone device 11 on the calling side is connected.
Is a sub-channel 2 which is a division of the connected channel 21.
Of 2 and 23, the sub-channel used for communication is selected. For example, if the sub-channel 22 is selected, the telephone device 11 sends data of a predetermined specific bit pattern onto the sub-channel 22.

On the other hand, the pattern detection unit 2 in the sub-channel control unit 7 (here, the sub-channel 22 is controlled) in the telephone device 12 has the sub-channel 22.
It constantly monitors the bit pattern of the data transferred above. When the pattern detection unit 2 detects the data of the specific bit pattern transmitted by the telephone device 11, it notifies the channel mode control unit 3 to that effect. Upon receiving the notification, the channel mode control unit 3 instructs the channel switching unit 4 to connect the designated sub-channel line to the connection control processing unit 5. The connection control processing unit 5 uses the connected sub-channel 22.
Perform subchannel connection control processing above. When the connection control processing in the connection control processing unit 5 ends, the connection control processing unit 5
Notifies the channel mode control unit 3 that the connection control processing has been completed. Channel mode control unit 3 that received the notification
Instructs the channel switching unit 4 to switch the connection of the sub-channel line from the connection control processing unit 5 to the call processing unit 6.
After that, communication is performed between the users.

In the first embodiment, channel 2 is used.
When the sub-channel 23 is first connected after the connection of 1, or when the other sub-channel 23 (or 22) is connected while one sub-channel 22 (or 23) is connected, the same procedure as above is performed. Connection control is performed with.

The sub-channel to be used first after the channel 21 is connected may be determined in advance among the telephone devices. In this case, for the connection of the first sub-channel after the connection of the channel 21, the above procedure is omitted and the predetermined sub-channel is automatically connected.

The initial state of the subchannel after the connection of the channel 21 may be set to the control mode, and the subchannel line may be connected to the connection control processing unit 5 in advance.
In this case, the procedure of switching the sub-channel line to the control mode after the channel 21 is connected is omitted, and the connection control information can be sent immediately after the channel is connected.

(3) Operation when disconnecting sub-channel Next, the operation when disconnecting the sub-channel being used for communication will be described. Now, the disconnection request side is the telephone device 11
And the subchannel to be disconnected is subchannel 2
Set to 2. The telephone device 11 sends data of a predetermined specific bit pattern onto the sub-channel 22.
As this bit pattern, the same pattern as that transferred at the time of connection can be used.

On the other hand, the pattern detector 2 of the telephone device 12
Constantly monitors the bit pattern of data transferred on the sub-channel 22 even during communication. Pattern detector 2
When the data of the specific bit pattern transmitted by the telephone device 11 is detected, the channel mode control unit 3 is notified.
Upon receiving the notification, the channel mode control unit 3 instructs the channel switching unit 4 to connect the sub-channel line to the call processing unit 6
To the connection control processing unit 5. Connection control processing unit 5
Performs a subchannel disconnection process on the connected subchannel 22.

When the connection control processing in the connection control processing unit 5 is completed, the telephone device 12 judges the connection status of the subchannel in the channel 21, and disconnects the channel 21 if there is no other subchannel in use. . When disconnecting the last sub-channel included in the channel 21, the control information is sent from one telephone device to the other telephone device out-of-band, and the sub-channel and the channel 21 are sent based on this control information. May be disconnected.

As described above, in the first embodiment, the sub-channel used for communication is switched to the control mode before the communication is started to transfer the connection control information, and then the sub-channel of the sub-channel is transferred based on this connection control information. Since connection control is performed, all subchannels can be used for data communication. Therefore, it is possible to improve the utilization efficiency of the line as compared with the conventional example in which a specific subchannel is dedicated to the transmission of connection control information.

Second Embodiment FIG. 3 is a schematic diagram showing an example of a connection state of telephone devices in a communication system which realizes a call connection control method according to a second embodiment of the present invention. Hereinafter, with reference to FIG. 3, the telephone device 11 and the telephone device 12 are used with the telephone device 13 as a relay station.
A sub-channel connection control operation in the case of performing detour relay communication with and will be described. In addition, such detour relay communication is
For example, if you want to communicate between Osaka (telephone device 11) and Tokyo (telephone device 13) while you are already communicating between Osaka and Yokohama (telephone device 12), you must pass between Tokyo and Osaka (telephone device 12). It is performed when communicating. In this case, since the communication between Osaka and Tokyo is performed using the empty sub-channel in the already connected channel, there is no charge communication and the communication cost can be saved.

Now, the channel 31 is already connected between the telephone device 11 and the telephone device 13, and communication is performed between the telephone device 11 and the telephone device 13 using a sub-channel not shown. I shall. In this case, the telephone device 11 selects an empty subchannel 33 in the channel 31 and sends data of a specific bit pattern to the telephone device 13 using this empty subchannel 33. In response, the telephone device 13 switches the empty subchannel 33 to the control mode. Next, the telephone device 11 transfers the bypass relay connection request including the address of the telephone device 12 to the telephone device 13 by using the empty subchannel 33. Telephone device 13
Receives a bypass relay connection request from the telephone device 11,
The request message is analyzed and the address of the telephone device 12 is extracted.

Next, the telephone device 13 uses the same procedure as in the first embodiment to establish a channel 32 with the telephone device 12.
Connected, and empty subchannel 3 in channel 32
4 is used to send data of a specific bit pattern to the telephone device 12. In response, the telephone device 12 switches the empty subchannel 34 to the control mode. Next, the telephone device 13 uses the idle subchannel 34 to
The incoming call request of the detour call from the telephone device 11 is transferred to the telephone device 2.
In response to this, the telephone device 12 performs the connection processing of the empty sub-channel 34. When the subchannel connection processing from the telephone device 11 to the telephone device 12 is completed, the subchannel 33,
The sub-channel 34 is switched to the communication mode, and communication is started between the telephone device 11 and the telephone device 12 via the telephone device 13.

In the second embodiment, the procedure for disconnecting the sub-channel used for communication is the same as the above-mentioned first procedure.
It may be similar to the embodiment of.

As described above, in the second embodiment, the sub-channel is used by switching it between the control channel and the communication channel, so that a specific signaling connection (sub-channel dedicated to connection control information transmission) is not provided. It is possible to perform connection control processing for the bypass relay connection. Therefore, the bypass relay communication can be realized without deteriorating the use efficiency of the line.

Third Embodiment FIG. 4 is a schematic diagram showing an example of a connection state of telephone devices in a communication system which realizes a call connection control method according to a third embodiment of the present invention. FIG. 5 is a diagram showing the stored contents of a storage unit (not shown) that stores the position information of the child device in the telephone device 13 of FIG. Hereinafter, the connection control operation of the sub-channel when the bypass relay communication is performed between the slaves will be described with reference to FIGS. 4 and 5.

In FIG. 4, the telephone device 12 and the telephone device 1
3 and between the telephone device 12 and the telephone device 14, channels are connected from the child device 41 to the child device 4 via the telephone device 11, the telephone device 13, and the telephone device 12.
A case of connecting to No. 2 will be described.

First, the slave unit 41 is connected to the telephone unit 11 by the slave unit 4.
Send a call request addressed to 2. Accordingly, the telephone device 11
In order to connect a sub-channel with the telephone device 12,
A call setup message is transmitted to the telephone device 12 out of band. At this time, since the telephone device 12 is using both of the B channels, the telephone device 12 returns a release completion message to the telephone device 11 and rejects the call. FIG. 6 shows an example of the format of the release completion message. As shown in FIG. 6, as the reason display of the release completion message, the addresses of the telephone devices 13 and 14 which are the connection destinations of the channels are set and the telephone device 11 is notified.

The telephone device 11 analyzes the reason display for rejecting the call in the release completion message and extracts the addresses of the telephone devices 13 and 14. After that, the telephone device 11
One of the two extracted addresses is selected as the relay destination terminal. Various methods can be considered for selecting the relay destination terminal, but the relay destination terminal is preferably selected so that a route with a low call charge can be established. The case where the telephone device 13 is selected as the relay destination terminal will be described below.

The telephone device 11 is different from the telephone device 13 in that
Send call setup messages out-of-band. FIG. 7 shows an example of the format of the call setup message. As shown in FIG. 7, the address of the telephone device 13 which is the connection destination of the channel is set in the called number information element, and the address of the slave device 42 which is the connection destination of the sub-channel is set in the sub address information element.

Upon receiving the call setup message from the telephone device 11, the telephone device 13 analyzes the sub-address information element contained therein and extracts the address of the child device 42.
When the handset device 42 is not registered in its own terminal, the telephone device 13 compares the position information of each handset device shown in FIG. 5 with the address of the handset device 42, and selects the handset device in which the handset device 42 is registered. Search for. According to the position information of FIG. 5, since it is the telephone device 12 that the cordless handset 42 is registered, the telephone device 13
Switches the idle subchannel with the telephone device 12 to the control mode in the same procedure as in the first embodiment. Then, the telephone device 13 adds the telephone number 12 to the called number information element.
, And the call setup message in which the address of the telephone device 42 is set in the sub-address information element, is transmitted to the telephone device 12 via the empty subchannel switched to the control mode.
Transfer to.

When the telephone device 12 receives the call setup message from the telephone device 13, the telephone device 12 analyzes the sub-address information element contained therein and extracts the address of the slave unit 42.
When the child device 42 is registered in the own terminal, the telephone device 12 transmits a call request to the child device 42 and notifies the incoming call.

Thereafter, in the same procedure as in the first embodiment described above, the empty subchannel between the telephone device 11 and the telephone device 13 and the empty subchannel between the telephone device 13 and the telephone device 12 communicate with each other. Switched to the mode, telephone device 1
A communication path is established between the telephone device 11 and the telephone device 12 using 3 as a relay terminal. After that, through this communication path,
Communication is started between the child device 41 and the child device 42.

In the third embodiment, the procedure for disconnecting the subchannel used for communication is the same as the above-described first procedure.
It may be similar to the embodiment of.

In the third embodiment described above, the position of the slave unit is determined from the position information stored in the telephone unit 13. However, according to the numbering plan, the telephone unit is set in advance in the address of the slave unit. You may make it judge the position of a subunit | mobile_unit by this including the content shown. Further, the sub-address may be transferred including the address of the telephone device. If the telephone device also has a tracking connection function for the child device, position registration information for tracking connection may be used as the position information in FIG.

As described above, in the third embodiment, the destination address is set as the sub address in the call setup message, so that no special procedure is required.
A bypass relay connection can be realized between the slaves.

[0051]

According to the invention of claim 1, since the connection control information is transferred through the selected arbitrary sub-channel, the connection control information is transmitted through the specific sub-channel as in the conventional example. Sub-channel connection control can be performed without dedicated allocation. Therefore, all the sub-channels can be used for communication, and the line utilization efficiency can be improved.

According to the second aspect of the present invention, the data transferred on each sub-channel is constantly monitored, and when the data having a predetermined specific bit pattern is detected, the sub-channel to which the data is transferred is detected. Is switched to the control mode, it is possible to smoothly shift to the control mode without causing confusion with the communication data even if the sub-channel is being used for communication.

According to the invention of claim 4, when the bypass relay communication is performed between the first terminal and the third terminal using the second terminal as a relay terminal, the first terminal and the second terminal Between the first terminal and the second terminal and the third terminal by subchannels switched to the control mode, and connection control information from the first terminal using the subchannels switched to the control mode. After sequentially transferring to the second and third terminals and performing the control processing for the bypass relay connection on each sub-channel that has been switched to the control mode based on the transferred connection control information, each sub-channel is switched. Since the mode is switched to the communication mode, the bypass relay communication using the sub-channel multiplex communication can be realized without lowering the utilization efficiency of the line.

According to the invention of claim 5, the first, second
And bypass relay communication is performed between the first slave unit registered in the first terminal and the second slave unit registered in the third terminal via the third terminal. In this case, the call setup message in which the address of the second child device registered in the third terminal, which is the destination address, is set as the sub address is sent to the first out via the outband of the digital communication network.
Of the second terminal based on the subaddress set in the received call setup message.
Is configured to execute sub-channel connection control with the third terminal, even if the first terminal and the second terminal
Even if communication is not being performed with the other terminal, the second terminal can be used as a relay terminal without providing a special procedure.
By-pass relay communication using subchannels can be realized between the first slave unit and the second slave unit.

According to the invention of claim 7, the first slave unit registered in the first terminal and the first slave unit registered in the second terminal are passed through the first and second terminals. When sub-channel multiplex communication is performed with the second handset, a call setup message in which the address of the second handset registered as the destination address of the second handset is set as the sub-address is transmitted by digital communication. Transferred from the first terminal to the second terminal via the out-band of the network, and based on the sub-address set in the received call setup message, the second terminal communicates with the second handset. Since the connection control is executed, it is possible to realize slave unit-slave unit communication using the sub-channel without performing a special procedure such as in-band communication.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a configuration of a sub-channel control unit that performs connection control per sub-channel in a telephone device in a communication system that realizes a call connection control method according to a first embodiment of the present invention. is there.

FIG. 2 is a schematic diagram showing an example of a connection state of telephone devices in the communication system that realizes the first exemplary embodiment of the present invention.

FIG. 3 is a schematic diagram showing an example of a connection state of telephone devices in a communication system that realizes a call connection control method according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing an example of a connection state of telephone devices in a communication system that realizes a call connection control method according to a third embodiment of the present invention.

5 is a diagram showing stored contents of a storage unit that stores position information of a child device in the telephone device 13 of FIG.

6 is a diagram showing an example of a message format of a release completion message used in the communication system of FIG.

7 is a diagram showing an example of a message format of a call setup message used in the communication system of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Demultiplexing unit 2 ... Pattern detection unit 3 ... Channel mode control unit 4 ... Channel switching unit 5 ... Connection control processing unit 6 ... Call processing unit 11-14 ... Telephone device 21 ... Channel 22, 23 ... Sub-channel 41, 42 …Cordless handset

Claims (7)

[Claims] 1. A method for controlling a sub-channel connection state between terminals in a communication system in which a channel connected to a digital communication network is divided into a plurality of sub-channels and a plurality of terminals perform multiplex communication. And a first step of switching an arbitrary subchannel selected from the plurality of subchannels to a control mode, and a connection required for connection control of the subchannel via the subchannel switched to the control mode. A second step of transferring control information; and a third step of controlling the connection state of the sub-channel to which the connection control information is transferred, based on the transferred connection control information.
And a call connection control method. 2. The second step constantly monitors data transferred on each of the sub-channels, and when data having a predetermined specific bit pattern is detected, the sub-channel to which the data is transferred is detected. The call connection control method according to claim 1, further comprising: switching the control mode to the control mode. 3. The call according to claim 1, wherein in the third step, the sub-channel switched to the control mode is switched to a communication mode after performing a predetermined connection process. Connection control method. 4. The detour relay communication between the first terminal and the third terminal, wherein the communication system includes three or more terminals having a detour relay connection function, and the second terminal is a relay terminal. In the first and second steps, the control mode is switched between the first terminal and the second terminal and between the second terminal and the third terminal, respectively. After connecting by the sub-channel, the connection control information is sequentially transferred from the first terminal to the second and third terminals using the sub-channel switched to the control mode, the third step, Based on the transferred connection control information, after performing a control process for a bypass relay connection on each sub-channel that has switched to the control mode, switch each sub-channel to a communication mode, Claim 1 The call connection control method described in. 5. A communication system in which a channel connected to a digital communication network is divided into a plurality of sub-channels and multiplex communication is performed between a plurality of terminals, each of which has a bypass relay connection function. By way of the detour relay communication between the first slave unit registered in the first terminal and the second slave unit registered in the third terminal via the third terminal. Then, the first terminal sends a call setup message in which the address of the second child device registered in the third terminal, which is a destination address, is set as a sub-address to the out-band of the digital communication network. Between the second terminal and the third terminal based on the sub-address set in the call setup message received from the first terminal. In subchannel And executes the connection control, call connection control method. 6. The second terminal, if the sub-address set in the received call setup message is not the address of the slave unit registered in the self-terminal, registers the slave unit indicated by the sub-address. The call connection control method according to claim 5, further comprising: searching a terminal that is present and transferring the call setup message to the searched terminal. 7. In a communication system in which a channel connected to a digital communication network is divided into a plurality of sub-channels and multiplex communication is performed between a plurality of terminals, the first and second terminals are used to pass the first communication. Is a method for performing communication between a first slave unit registered in the second terminal and a second slave unit registered in the second terminal, wherein the first terminal is a destination address. A call setup message in which the address of the second child device registered in the second terminal is set as a sub-address is transferred to the second terminal via the outband of the digital communication network, The second terminal executes connection control with the second handset based on the sub-address set in the call setting message received from the first terminal. Call connection control method.