JPH0457436A - Method and apparatus for communication using isdn line - Google Patents

Abstract

PURPOSE:To attain data communication by using a call setting sequence so as to absorb a delay difference of received data through channels B1 and B2 thereby establishing the synchronization between the channels B1 and B2 and synthesizing the channels B1 and B2. CONSTITUTION:A terminal adaptor 3 sends a call setting message for channels B1 and B2, and when the call setting reception message is received by the channels B1 and B2, a synchronization pattern 1 is sent to each ISDN exchange network 13 through the channels B1 and B2. A terminal adaptor 6 detects a change in a synchronization pattern from the synchronization pattern 2 to the channels B1 and B2 having been received from the terminal adaptor 3 into a synchronization pattern 3 respectively, then the terminal adaptor 6 controls a data buffer or the like based on a transmission delay difference to absorb the transmission delay difference thereby establishing the synchronization between the channels B1 and B2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a communication method using an ISDN line, and in particular, a communication method that uses a plurality of communication channels at the same time and combines the data speeds of the plurality of communication channels. The present invention relates to a communication method and device using an industrial SDN line for performing one communication depending on the communication speed.

[Conventional technology]

The ISDN basic interface is configured to set up one B channel (64 kbpS) with one call connection. Therefore, in a conventional communication method using an ISDN line, the highest data rate of the line that can be transferred by one call connection is the data rate of one B channel (64 kbps), and data at a rate of 64 kbps or higher is transmitted and received. When performing digital communication, a digital leased line or primary rate interface was used.

As a method to solve this problem, the ISDN basic interface uses two channels, B1 and B2, at the same time, thereby making it possible to support communication speeds of up to 128 kbps.

[Problem to be solved by the invention]

However, as described above, both the B1 and B2 channels cannot be set at the same time by one call connection, so it is necessary to connect the B1 channel and the B2 channel individually.

If a call connection is made for each channel in this way, the connection route will be different for each channel. Therefore, a difference occurs in the propagation delay time of each channel, resulting in a problem that the received data and the transmitted data are different.

An object of the present invention is to provide a communication method that can absorb the difference in propagation delay time between the B1 channel and the B2 channel and accurately transmit and receive data even when the B1 channel and the B2 channel are used simultaneously. It is in.

[Means to solve the problem]

The present invention simultaneously sends predetermined data to multiple channels at the time of call setup, and on the side receiving the data, accumulates the data for other channels until the channel that receives the data finally receives the data. However, when the data is received on all channels, this can be achieved by rearranging the data on all channels in a predetermined order and establishing synchronization of all channels.

[Effect]

A sequence for establishing synchronization between the B1 channel and B2 channel is added during the call setup sequence, and in this sequence, the synchronization pattern (Bl channel and B2 channel) from the transmitting side is added.
(transmitted on two channels), the reception timing is detected, the data of the other channel is accumulated until the synchronization pattern is received on the slower channel, and the data is transmitted on both the B1 channel and B2 channel. When channel data is received, the B1 channel and B2 channel are combined into one channel and output.

This allows the B1 channel and B
Absorbs the delay (time) difference in received data between the two channels,
Synchronization between the B1 channel and the B2 channel can be established, and data communication can be performed by combining the B1 channel and the B2 channel.

〔Example〕

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

FIG. 1 is a diagram showing the configuration of a system that simultaneously uses the B1 channel and B2 channel of the ISDN basic interface and transfers image information at a communication speed of 128 kbps.

In FIG. 1, an image signal captured by a video camera 1 is converted from an analog signal to a digital signal by an image codec device 2, and is outputted to an output signal line 4 by a terminal adapter 3.

The signal is sent to the input signal line 5 via the ISDN switching network 13. The terminal adapter 6 outputs the image signal received from the input signal line 5 to the image codec device 7. The image signal is then converted into an analog signal by the image display device 7 and sent to the video monitor 8. Similarly, the image signal captured by the video camera 9 is transmitted to the image codec device 7, the terminal adapter 6, the output signal line 10, the IS, the DN exchange network 13, the input signal line 11, the terminal adapter 3, and the image knee deck. It is outputted via the device 2 to the video monitor 12.

FIG. 2 is a diagram showing a signal transmission format between the terminal adapter 6 and the ISDN switching network 13.

This format includes two data transfer channels B1 and B2 with a data rate of 64 kbps, a D channel for call control with a data rate of 16 kbps, and other features such as framing pits, DC balance bits, D echo channel bits,
It consists of auxiliary frame bits, etc. Note that this format is used as the ISDN basic interface.

Figure 3 shows a call control sequence using the D channel for incoming and outgoing calls, and a call control sequence using the B1 channel and B2 channel simultaneously.
FIG. 3 is a diagram showing a sequence when communicating at a data transfer rate of 8 kbps, that is, a sequence for establishing synchronization between a B1 channel and a B2 channel.

FIG. 4 is a block diagram showing the internal configuration of the terminal adapter.

In FIG. 4, 403 is an ISDN interface circuit that interfaces with the ISDN switching network 13;
02 is a synchronization pattern sending circuit that generates a synchronization pattern to be sent on the B channel; 412 is a B channel data storage circuit that temporarily stores data on the B channel; 417
416 is a switching circuit, and 416 is a B channel data storage circuit 412.
406 is a switching circuit controlled by the synchronization pattern sending circuit, 425 is a B1 channel synchronization pattern detection circuit that detects synchronization pattern 1 on the B1 channel, and 426 is a B2 channel synchronization pattern detection circuit.
A B2 channel synchronization pattern 1 detection circuit detects synchronization pattern 1 on the channel, 410 a B1 channel synchronization pattern 2 detection circuit for detecting synchronization pattern 2 on the B1 channel, and 411 a synchronization pattern 2 on the B2 channel.
B2 channel synchronization pattern 2 detection circuit for detecting 41
4 detects synchronization pattern 3 on B1 channel B]-
Channel synchronization pattern 3 detection circuit 415 is a B2 channel synchronization pattern 3 detection circuit for detecting synchronization pattern 3 on the B2 channel, 405.407 to 409.418.
420, 423, 424, and 428 to 430 are signal lines of each circuit.

The operation will be explained below based on FIG.

When calling from terminal adapter 3, call setup message [B1] connects B1 channel by D channel.
, and a call setup message connecting the B2 channel [B1
1 to the ISDN switching network 13. At this time, channel information is set in the information element 1 "subaddress" in the call setting message so that the terminal adapter 6 on the receiving side can determine which channel it corresponds to.

Call setup message sent by terminal adapter 3 [B
11. A call setup acceptance message [B11, [B11] is returned from the ISDN switching network 13 to [B11. As a result, the B1 and B2 channels are connected to the ISDN switching network, and synchronization pattern 1 is sent to the ISDN switching network 13.

On the other hand, the terminal adapter 6 on the called side receives the call setting messages [B11, [B1] from the ISDN switching network 13.
Response message of the same channel as the B channel specified by the information element "Caller subaddress" of No. 1 [B11, [B1
1 information element "channel identifier" and sends it to the ISDN switching network 13. In response to the response message, IS
Response confirmation message from the DN exchange network [B11, [B11
is returned, thereby connecting the B channel to the TSDN switching network 13 and starting a synchronization sequence by the B channel.

Next, the synchronization sequence using the B channel will be explained.

The terminal adapter 3 sends the call setup message for the B1 and B2 channels, and upon receiving the call setup acceptance message for each channel, sends the synchronization pattern 1 from the B1 and B2 channels to the ISDN switching network 13.
Send to.

On the other hand, when the response confirmation message arrives for each channel of B1 and B2, the terminal adapter 6
By sending synchronization pattern 1 from channels 1 and B2, and then sending synchronization pattern 2, terminal adapter 3 confirms that the B channel is connected normally.
Usually.

Here, by switching from synchronization pattern 1 to synchronization pattern 2, information can be notified more reliably.

Note that at this time, the terminal adapter 6 is in a state in which it is receiving the synchronization pattern 1 that continues to be sent out from the terminal adapter 3 (not shown).

On the other hand, in terminal adapter 3, the B1 channel and
Sync pattern 1 and sync pattern 2 from 2 channels respectively
, and recognizes that the B1 channel and B2 channel are respectively connected normally. Recognizing that the B1 channel and B2 channel are connected normally, the terminal adapter 3 simultaneously sends synchronization pattern 2 to the B1 channel and B2 channel, and then
The synchronization pattern 3 is transmitted simultaneously to the channel and the B2 channel, and the synchronization pattern to be transmitted is switched from the synchronization pattern 2 to the synchronization pattern 3 at the same time. .

The terminal adapter 6 detects that the synchronization pattern 2 for the B1 channel and the B2 channel, which has been continuously being received from the terminal adapter 3, has changed to the reception of the synchronization pattern 3, respectively. At this time, B
If the time when channel 1 changed from synchronization pattern 2 to synchronization pattern 3 is earlier than the time when channel B2 changed from synchronization pattern 2 to synchronization pattern 3, the time when channel B1 changed from synchronization pattern 2 to synchronization pattern 3 is As a reference, the time difference between the times when the B2 channel changes from synchronization pattern 2 to synchronization pattern 3 is calculated and detected, and the calculation result is used as the data transmission delay difference between the B1 channel and the B2 channel. In addition, if the time when the B2 channel changed from sync pattern 2 to sync pattern 3 is earlier than the time when the B1 channel changed from sync pattern 2 to sync pattern 3, the time when the B2 channel changed from sync pattern 2 to sync pattern 3 is As a reference, calculate (detect) the time difference between the times when the B1 channel changes from synchronization pattern 2 to synchronization pattern 3, and use the calculation result as the difference between the B2 channel and the B1 channel.
This is the data transmission delay difference for one channel.

This allows the terminal adapter 6 to recognize the transmission delay difference between the B1 channel and the B2 channel received from the terminal adapter 3.

Then, based on the transmission delay difference, the data buffer etc. are controlled to absorb the transmission delay difference and connect the B1 channel and the B2 channel.
Performs actions to establish channel synchronization.

After that, the terminal adapter 3 displays a communication enable display to the image copier 2 indicating that communication is possible, and sends a synchronization pattern 3 to the terminal adapter 6, requesting the start of communication. The image data received from the image copier 2 is divided into the B1 channel and the B2 channel and sent to the terminal adapter 6.

On the other hand, the terminal adapter 6 is the terminal adapter 3
When the synchronization pattern 3 is received from the B1 channel and the B2 channel from Send the amount to B2 channel at the same time.

When terminal adapter 3 receives synchronization pattern 3, the B1 channel changes from synchronization pattern 2 to synchronization pattern 3.
, and the time when the B2 channel changed from synchronization pattern 2 to synchronization pattern 3, the B1 channel and B2 channel are transmitted from the terminal adapter 6 to the terminal adapter 3 using the same procedure as for the terminal adapter 6 described above. A delay difference is determined, a data buffer, etc. is controlled based on the data transmission delay difference, and synchronization between the B1 channel and the B2 channel is established.

Through the above sequence, synchronization between the B1 channel and the B2 channel is established through bidirectional transmission and reception between the terminal adapter 3 and the terminal adapter 6, and image data is transmitted and received.

When the data communication is completed, the image copier 2 sends disconnection instruction information to the terminal adapter 3. When the terminal adapter 3 detects this disconnection instruction information, it recognizes that the data communication has ended, and sends a disconnection message [B1
], [B2] are sent to the ISDN switching network 13. In response, a release message [B
11. [When B11 is received, the B1 channel and B2 channel are disconnected from the ISDN line, the sending of the communication possible display information to the image copier N2 is stopped, and the I
Release completion message to SDN switching network 13 [B11, [B
11 is sent.

On the other hand, when the terminal adapter 6 receives the disconnection message [B11, [B11] from the ISDN switching network 13,
At the same time as disconnecting the B1 channel and B2 channel from the IS'DN line, the output of communication enable display information to the image copier 7 is stopped, and release messages [B11, [B11] are sent to the ISDN switching network 13, and the ISDN switching network 1
3 receives the release completion message [B11, [B11], and ends the communication.

Next, the operation of the terminal adapter shown in FIG. 4 when making a call will be explained.

First, the image cooperating device connects the I
Activates transmission to the SDN interface circuit 4C)3. In response to the activation request, the ISDN interface circuit 403 sequentially sends a call setting message [B11] and a call setting message [B11] to the ISDN switching network 13 via a signal line (transmission line) 404. On the contrary,
When the DSN interface circuit 403 receives the call setup acceptance message [B11] from the ISDN switching network 13 via the signal line (receiving line) 422, it sends activation information to the synchronization pattern sending circuit 402 via the signal line 405. The synchronization pattern sending circuit 402 is activated, and a call setting acceptance message [B11 is sent via the signal line 422]
When the SDN interface circuit 403 receives the activation information, it sends activation information to the synchronization pattern transmission circuit 402 via the signal line 423, and activates the synchronization pattern transmission circuit 402. Furthermore, the ISDN interface circuit 403
The signal line 404 and the signal line 402 are connected, and the signal line 422 and the signal line 408 are connected, respectively.

The synchronization pattern sending circuit 402 controls the switching circuit 406 using a signal B420, and connects the signal line 430 and the signal line 407. Next, the synchronization pattern sending circuit 402
It is sent from the N interface circuit 4゜3 and is connected to the signal line 42.
synchronization pattern 1 (8-bit data all') for the corresponding B channel in synchronization with the signal transmitted via
0') is sent out continuously.

Next, when the ISDN interface circuit 403 receives a signal in the format shown in FIG. The signal is recognized, converted into the format shown in FIG. 2, and sent to the signal line 404.

Further, the ISDN interface circuit 403 is connected to the signal line 4.
The signal received from 22 is converted into a signal in the format shown in FIG.
B2 channel synchronization pattern detection circuit 426, B1 channel synchronization pattern 2 detection circuit 410, B2 channel synchronization pattern detection circuit 411, B1 channel synchronization pattern 3 detection circuit 414, B2 channel synchronization pattern 3 detection circuit 4
15, and the B channel data storage circuit 412.

Note that each circuit to which the signal line 424 is connected can identify the B1 channel and the B2 channel based on the signal sent from the signal line 424.

When the B1 channel synchronization pattern 1 detection circuit 425 and the B2 channel synchronization pattern 2 detection circuit 426 detect 'n1' octets of synchronization pattern 1 (8-bit data all '0'), the B1 channel synchronization pattern 2 detection circuit 425
10 and B2 channel synchronization pattern 2 detection circuit 411 is activated.

Furthermore, when the B1 channel synchronization pattern 2 detection circuit 410 and the B2 channel synchronization pattern 2 detection circuit 411 detect 'n2' octets of synchronization pattern 2 (8-bit data all '1'), the B1 channel synchronization pattern 3 detection circuit 414, B2 channel synchronization pattern 3 detection circuit 41
5 and the synchronization pattern sending circuit 402 is activated.

When the synchronization pattern sending circuit 402 receives activation requests from both the B1 channel synchronization pattern 2 detection circuit 410 and the B2 channel synchronization pattern detection circuit 411, the synchronization pattern sending circuit 402 simultaneously switches the synchronization pattern 2 to both the B1 channel and the B2 channel. 406, 'n2' octets are sent to the signal line 404 via the ISDN interface circuit 403, and then synchronization pattern 3 (8-bit data all 'O') is sent.
') is simultaneously sent to both the B1 channel and the B2 channel in the same way as 'n3' octets.

Furthermore, after sending out the synchronization pattern 2, the synchronization pattern sending circuit 402 displays a communication enable display to the image copier through the signal line 419, and controls the switching circuit 406 via the signal line 420 to transmit the image from the image copier. Data is transferred to the signal line 421, switching circuit 406, signal line 40
7 and the ISDN interface circuit 403 to enable transmission to the signal line 404. Note that the image copier 7 transmits the image data after the time for transmitting n3' octets has elapsed after receiving the communicable indication.

Next, when either the B1 channel synchronization pattern 3 detection circuit 414 or the B2 channel synchronization pattern 3 detection circuit 415 detects the synchronization pattern 3, the other B channel detects the synchronization pattern based on the detected time. 3 (detected) time difference (Bl channel and B
The data storage input/output control circuit 406 detects the data transmission delay difference between the two channels, and controls the B channel data storage circuit 412 based on the data transmission delay difference.

The B channel data storage circuit 412 absorbs the data transmission delay difference between the B1 channel and the B2 channel under the control of the data storage input/output control circuit 406, and
Establish synchronization with 2 channels. Note that a detailed explanation of the operation for establishing this synchronization will be given later.

When the data communication is completed and the ISDN interface circuit 403 receives a disconnection instruction from the image copier via the signal line 401, the ISDN interface circuit 403
3 sends a disconnection message etc. to the signal line 404 and performs the disconnection process according to a predetermined procedure.

Next, the operation of the terminal adapter when receiving a call will be explained.

First, the ISDN interface circuit 403 connects the signal line 4
22, when a call setting message [BI3 and call setting message [B2] is received, a response message [BI3
and a response message [B2] is sent from the signal line 404. In response, when the ISDN switching network sends a response confirmation message [BI3 and response confirmation message [B2] and receives it via the signal line 422, the signal line 405 activates the synchronization pattern sending circuit 402, and the signal line 404 and signal line 407 and signal line 422 and signal line 4
08 respectively.

When activated by the ISDN interface circuit 403, the synchronization pattern sending circuit sends out `01' octets of the synchronization pattern 1 to the B1 channel and the B2 channel, respectively, and then continuously sends out the synchronization pattern 2.

Note that at this time, the B1 channel synchronization pattern 1 detection circuit 425 and the B2 channel synchronization pattern 1 detection circuit 426
detects the synchronization pattern 1, and then the B1 channel synchronization pattern 2 detection circuit 410 and the B2 channel synchronization pattern 2 detection circuit 411 detect the synchronization pattern 2.

Next, when the B1 channel synchronization pattern 3 detection circuit 414 or the B2 channel synchronization pattern 3 detection circuit 415 detects the synchronization pattern 3, the data accumulation input/output control circuit 4
16. The operation of the data storage input/output control circuit 416 is controlled by connecting the signal line 403 to the ISDN interface circuit 403.
It differs depending on the relationship between the B1 channel and the B2 channel input via 8.

The operation of the data storage input/output control circuit 416 will be explained below with reference to FIGS. 6, 7, and 8.

First, FIG. 6 is a diagram illustrating a case where there is no difference in reception delay (time) between data on the B1 channel and the B2 channel. When the data accumulation input/output control circuit 416 determines that there is no reception delay difference between the B1 channel and the B2 channel, it activates the switching circuit 417 via the signal line 428,
Signal line 408 and signal line 427 are logically directly connected.

Next, FIG. 7 shows that the B2 channel is compared to the B1 channel,
FIG. 6 is a diagram illustrating a case where a message is received with a delay. When activated by the B1 channel synchronization pattern 3 detection circuit 414, the data accumulation input/output control circuit 416 activates the B channel data accumulation circuit 412 via the signal line 418, and data D1, B3 after receiving the synchronization pattern of the B1 channel. ,・
Accumulate... After that, B2 channel synchronization pattern 3
When the detection circuit 415 detects synchronization pattern 3 and is activated by the synchronization pattern 3 detection circuit 415, the B channel data storage circuit 412 is activated through the signal line 409, and the switching circuit 417 is activated through the signal line 428. . The B channel data storage circuit 412 also controls the stored data D1 under control from the signal line 409.
, B3, . . . are sequentially output to the signal line 429. The switching circuit 417 alternately connects the signal line 429 and the signal line 408 to the signal line 427 under control from the signal line 428, and outputs the received data (image data) to the image copier.

Finally, FIG. 8 is a diagram illustrating a case where the B1 channel receives data later than the B2 channel. When the data accumulation input/output control circuit 416 is activated by the B2 channel synchronization pattern 3 detection circuit 415, the signal line 41
8 activates the B channel data storage circuit 412, and
Data D2, B after receiving synchronization pattern 3 of 2 channels
4. Accumulate... After that, when the B1 channel synchronization pattern 3 detection circuit 414 detects the synchronization pattern 3 and is activated by the synchronization pattern 3 detection circuit 414, the B channel data storage circuit 412 is activated by the signal line 409, and switching is performed by the signal line 428. Activate circuit 417. The B channel data storage circuit 412 also stores data D2, which is stored under control from the signal line 409.
B4, . . . are output to the signal line 429. Switching circuit 417
Under the control of the signal line 428, the signal line 429 and the signal line 408 are alternately connected to the signal line 427, and data (image data) is output to the image copier.

Through the above operations, the data reception delay difference between the B1 channel and the B2 channel is absorbed, synchronization between the B1 channel and the B2 channel is established, and data is transferred.

Next, the data communication is completed and the ISDN
N interface circuit 403 disconnects message [B1]
and disconnection message [B2] is received, the signal line 40
1, a signal is sent to the image copier to stop displaying that communication is possible, and a disconnection process is performed according to a predetermined procedure.

The above operations establish synchronization between the B1 channel and the B2 channel, and it becomes possible to perform communication using both the B1 channel and the B2 channel by dividing one data (128 kbps).

〔Effect of the invention〕

According to the present invention, it is possible to absorb the difference in received data transmission delay time between the B1 channel and the B2 channel. This makes it possible to perform data communication at a maximum transmission speed of 128kbps by using both the B1 channel (64kbps) and B2 channel (64kbps) as one channel, so the basic interface ISDN
Lines can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing the configuration of an image information transfer system that is an embodiment of the present invention, FIG. 2 is a diagram showing the signal format of the ISDN line of the basic interface, and FIG.
4 is a block diagram showing the internal structure of the terminal adapter of the present invention; FIG. 5 is a diagram showing the format of the B channel in the terminal adapter of the present invention; FIG. 6, FIG. 7, and FIG. 8 are diagrams for explaining the operation of the terminal adapter of the present invention when receiving data. l, 9...Video camera, 8.12...Video monitor, 3.6...Terminal adapter, 2.7...Image copier, 4.5.10.11...Subscriber line, 403...ISDN interface circuit, 402...
・Synchronization pattern sending circuit, 406.417...Switching circuit, 425...B1 channel synchronization pattern 1 detection circuit, 4
26...B2 channel synchronization pattern 1 detection circuit, 41
0...B1 channel synchronization pattern 2 detection circuit, 411
... B2 channel synchronization pattern 2 detection circuit, 414.
...B1 channel synchronization pattern 3 detection circuit, 415...
・B2 channel synchronization pattern 3 detection circuit, 412...
B channel data accumulation circuit, 416... data accumulation input/output control circuit.

Claims (1)

[Claims] 1. At the time of call setup, predetermined data is simultaneously sent to multiple channels, and on the side receiving the data, the data is sent to other channels until the channel that receives the data finally receives the data. A communication system using an ISDN line, which is characterized in that when data is accumulated on all channels and the data is received on all channels, the data on all channels is rearranged in a predetermined order to establish synchronization of all channels. 2. Means for simultaneously transmitting predetermined data to a plurality of channels; means for accumulating data on other channels until the last channel to receive the data receives the data; and means for receiving the data on all channels. IS characterized by providing means for rearranging the data of all the channels in a predetermined order when the IS
A communication device using a DN line. 3. In a communication device using an ISDN line connected to an ISDN line, a B channel data communication circuit is provided with a data storage means and a means for identifying the beginning of received data, and the means for identifying the beginning includes: A communication device using an ISDN line, characterized by controlling a data storage means and transmitting data from the data storage means at a fixed timing.