JPH04107028A - Data communication connection device, data communication system and data communication method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a data communication connection device and a data communication system, and particularly relates to a line termination on the central office side that communicates data with the central office side via a transmission line. A data terminal device side line terminating device that communicates data between the device and the data terminal device side via a transmission line, and a data terminal device side line terminating device disposed between the central office side line terminating device and the data terminal device side line terminating device. A data communication system consisting of a data communication connection device,
and the data communication connection device used in this data communication system.

[Conventional technology]

As a conventional technique, for example, as described in Japanese Patent Publication No. 64-8943, data signals sent from a central office communication control device via a modulation/demodulation device and a branching device are divided into multiple data signals using a polling/selecting method. All data terminal devices receive the response request signal at the same time, and only the data terminal device that receives the response request signal from the central office communication control device sends out the transmission request signal and time-shares it to establish data communication with the central office communication control device. There are known methods that perform this process.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, no consideration is given to the case where the connection from the branching device to the data terminal device is performed via a modulation/demodulation device. In other words, due to reasons such as a long distance between the branching device and the data terminal device, the connection between the branching device and the data terminal device is connected to the modem, transmission line, or data terminal device connected to the branching side of the branching device. No consideration is given to the case where the connection is made by a connected modem. As a result, in the prior art, when connecting a branching device to a data terminal device via a modulation/demodulation device, there are the following problems. That is, when on/off control of a carrier signal is performed between a modem connected to the branch side of a branching device and a modem connected to a data terminal device, the modem connected to the data terminal device It was necessary to make the transmittable signal output in response to the transmission request signal from the transmitter sufficiently large. That is,
The modem connected to the data terminal equipment determines the time it takes for the data channel reception carrier detection signal that the modem connected to the central office transmission line outputs to the branching equipment to turn on, and the time it takes for the data channel reception carrier detection signal to be transmitted from the modem to the branching equipment. It is necessary to output the transmittable signal for a longer time than the sum of the time until the transmittable signal is turned on. Otherwise, the result will be that the first part of the transmission data transmitted from the data terminal device cannot be transmitted to the central office side.

Next, the above-mentioned problems of the prior art will be explained in more detail with reference to FIGS. 4 and 5.

FIG. 4 is a block diagram showing an example of the configuration of a data communication system in which connection from a branching device to a data terminal device is performed via a modulation/demodulation device, and FIG. 5 is a time chart for explaining its operation. It is. As shown in Figure 4,
A communication control device 2 is connected to a central processing device 1 of a central station,
The communication control device 2 is connected to a transmission line 12 via a modem device 3 . The transmission line 12 is connected to the AC branching device 4
It is connected to transmission line 8!13.14 via. The transmission line 13 is connected to a DC branching device 6 via a modem 5, and the branching side of the DC branching device 6 is connected to a modem 7.
and is connected to a data terminal device 9 via a transmission line 15 and a modem device 8. Furthermore, the transmission line 14 is connected to the data terminal device 11 via the modem 10.

In the communication system shown in FIG. 4, when a polling signal is sent from the communication control device 2 to the data terminal device 9 by the polling/selecting method, the modem device 3, the transmission line 12, the AC branching device 4, the transmission line 5, the data is transmitted to the data terminal device 9 via the DC branching device 6, the modem 7, the transmission line 15, and the modem 8. As a result, the data terminal device 9 and the like respond as shown in FIG. That is, as shown in the timing chart of FIG. 5, the transmission request signal R output from the data terminal device 9
When 8I is turned on, the modulation/demodulation device 8 outputs the training data as a carrier signal CRI to the modulation/demodulation device 7 via the transmission line 15.

Outputting the carrier signal CRI is generally performed in the case of high-speed data transmission. The modulation/demodulation device 7 sets internal fixtures and the like based on the training data in the received carrier signal. The modulator/demodulator 7 then turns on the data channel reception carrier detection signal CD2 and sends it to the DC branching device 6.

Next, the DC branching device 6 receives the data channel reception carrier detection signal CD2, turns on the transmission request signal RS3, and outputs it to the modulation/demodulation device 5.

Like the modem/demodulator 8 described above, the modulator/demodulator 5 sends training data as a carrier signal CR3 to the modem/demodulator 3 via the transmission line 13 and the AC branching device 4, and then sends the transmittable signal C33 to the DC branch. Send to device 6. Then, when the transmittable signal C81 is output from the modem 8 to the data terminal device 9, the data terminal device 9 outputs the transmission data signal SD, and the modem 8, the transmission line 15, the modem 7, and the DC branch The device 6, the modem 5, the transmission line 13, the AC branching device 4, and the modem 3
and is transmitted to the central processing unit 1 via the communication control device 2.

However, in the above-described conventional technology, a control signal indicating that data transmission is possible cannot be directly transmitted from the DC branching device 6 to the transmission line 15 via the modulation/demodulation device 7. Therefore, as shown in FIG. 5, in the modulation/demodulation device 8, the time TC51 from when the transmission request signal RSI is turned on until the transmission clear signal C81 is turned on is generally calculated as follows.
The setting is made so that TC3I≧(TCD2+TCS3), so that the beginning of the transmission data signal SD from the data terminal device 9 is not lost in the modulation/demodulation device 5.

Here, TDC2 is the time from when the transmission request signal R8I is turned on until the data channel reception carrier detection signal is turned on, and TCS3 is the time from when the data channel reception carrier detection signal is turned on until the transmission clear signal C33 is turned on. It's time. Therefore, in the prior art, the transmission time of the transmission data signal SD is the time CTC31-(TC
D2+TC, 53)), and furthermore, it takes time and effort to set the time TC5I in the modulator/demodulator 8.

The present invention was made in view of the problems of the prior art described above, and after a transmission request signal is output from a data terminal device,
This eliminates the need to set a sufficiently long time until a ready-to-transmit signal is output from the modulation/demodulator connected to the data terminal equipment (TC8I described above), and allows all data transmitted from the data terminal equipment to be sent to the central processing unit. It is an object of the present invention to provide a data communication connection device and a data communication system that enable normal data transmission.

[Means to solve the problem]

A first data communication connection device of the present invention includes a central office side line termination device that communicates data with the central office side via a transmission line, and a data terminal device side that communicates data via a transmission line. This is applied to a data communication connection device placed between the line terminating device on the data terminal side that communicates, and stores the data transmitted via the line terminating device on the data terminal device side. The present invention is characterized in that it includes means for reading and transmitting the read data to the central office side line terminating device.

A second data communication connection device of the present invention includes a central office side line termination device that communicates data with the central office side via a transmission line, and a data terminal device side that communicates data via a transmission line. The present invention is applied to a data communication connection device disposed between a communicating data terminal device and a line termination device, and has the following characteristics. That is, at least the first means for receiving the data channel reception carrier detection signal transmitted from the data terminal device side line termination device, and the first means receiving the data channel reception carrier signal, the central office side a second means for transmitting a transmission request signal to the line termination device; and a third means for storing data transmitted from the data terminal device when the first means receives the data channel reception carrier signal.
means for reading data from the third means in response to the transmission clear signal from the central office side line terminating device; and fifth means for transmitting data to the side line termination device.

The first data communication system of the present invention also provides a central office, a central office side line termination device that communicates data via a transmission line between the central office, a data terminal device, and a data terminal device. A data communication system consisting of a line terminating device on the data terminal side that communicates data via a transmission line, and a connecting device for data communication placed between the line terminating device on the central office side and the line terminating device on the data terminal side. The line terminating device on the data terminal device side transmits a signal based on the transmission request to the data communication connection device in response to a transmission request from the data terminal device, and After a period of time, a first transmission enable signal is sent to the data terminal device, the data terminal device starts transmitting data in response to the first transmission enable signal, and the data communication connecting device responds to the signal based on the transmission request. In response, a transmission request signal is sent to the line terminating device on the central office side, and the line terminating device on the central office side responds with a second transmission enable signal, thereby establishing the connection for data communication. The apparatus includes a storage means, starts data transmission from the data terminal device to the connection device before the second transmission clear signal and stores the data in the storage means, and the connection means receives the second transmission clearance signal. The present invention is characterized in that the data is read out from the storage means and transmitted to the line termination device on the central office side in response to the above.

Further, the second data communication system of the present invention includes a central office side line termination device that communicates data with the central office side via a transmission line, and provides mutual communication between the data terminal device side and the central office side. It is applied to a data communication system that communicates data with other people, and has the following characteristics. That is,
The central office side line termination device includes a first means for transmitting a transmission enable signal to the data terminal side by receiving a transmission request signal transmitted from the data terminal side; After transmitting the signal, there is a second means for storing the data transmitted from the data terminal device side, and after completion of transmission preparation in the line termination device on the central office side, the data is read from the second means and the data is stored on the central office side. The present invention is characterized in that it includes a third means for transmitting data to.

[Effect]

According to the first data communication connection device of the present invention, data transmitted from the line termination device on the data terminal device side is once stored, and then the stored data is read out and transmitted to the line termination device on the central office side. All data can be sent to the central office without missing the beginning of the data.

According to the second data communication connection device of the present invention, after the transmission request signal from the line terminating device on the data terminal device side is turned on, data transmitted from the line terminating device on the data terminal device side is stored, and the data transmitted from the line terminating device on the data terminal device side is stored. After the transmit enable signal from the side line termination device is turned on, it reads the stored data and sends it to the central office side line termination device, so that the data sent from the data terminal device is completely transferred during data communication. The data will be stored in the connecting device and the data will then be transmitted. Therefore, all data can be transmitted to the central station without missing the leading part of the data.

Further, according to the first data communication system of the present invention, after the data terminal device-side line terminating device receives the transmission request signal output from the data terminal device, it sends out a transmission enable signal to the data terminal device. It is possible to provide a data communication system that does not require any configuration.

Further, according to the second data communication system of the present invention, the data transmitted from the data terminal device is completely stored in the line termination device on the central office side, and then the stored data is read out and transmitted to the central office side. Ru. Therefore, all data can be transmitted to the central office without missing the leading part of the data.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing an improved DC branching device which is an embodiment of the data communication connection device of the present invention, and corresponds to the DC branching side 6 of the communication system shown in FIG. In FIG. 1, transmission data SD (data output from data terminal device 9) transmitted from modem 7 on the branch side is taken into jitter absorption circuit 101 together with transmission element timing signal 5T1a, and modulated and demodulated on the central station side. It is output at the output timing of the transmission element timing signal 5T20 output from the device 5. The output transmission data SD is the same as the transmission data O received from another data terminal device (not shown).
The signal is input to the storage unit 103 via the R circuit 102. The storage unit 103 is set to write mode by a write signal output from the write timing control unit 104, and the transmission data SD is stored at an address specified by an address signal output from the write address control unit 105. Ru.

The storage unit 103 is set to the continuous read mode by the read signal output from the continuous timing control unit 106, and the stored transmission data SD is read from the address indicated by the address signal output from the continuous address control unit 107. The read transmission data SD is transmitted to the modem 5 on the central station side.

The data channel reception carrier detection signal CD2 outputted from the branch side modem 7 to the central office side modem 5 is input to the transmission request control section 108 via the carrier reception data OR circuit 109. The transmission request control unit 108 sends a transmission request signal RS3 to the modem device 5 on the central station side.
and receives a transmittable signal CS3 from the modem 5.

The transmission request control unit 108 also controls the write address control unit 1.
05 and the read address control unit 107 to control the sending of the write address signal and the sending of the subsequent address signal. As described above, the write address control section 105 and the read address control section 107 output the write address and read address of the storage section 103, and also control the write timing control section 104 and the successive timing control section 106. As shown in the figure, the transmission element timing signal 5T20 from the modem 5 on the central office side is transmitted not only to the jitter absorption circuit 101 but also to a write timing control section 104, a write address control section 105, and a continuous timing control section 10.
6 is input to the read address control section 107 and used for timing control of each section.

FIG. 2 is a block diagram showing a specific example of the transmission request control section 108 shown in FIG. 1. When the aforementioned data channel reception carrier detection signal CD2 turns on, the write start circuit 20
1 turns on the write start signal to the write address control unit 105, and turns on the transmission request signal R33 output from the transmission request circuit 204. Transmittable signal C from modem 5
53, the continuation start circuit 203 turns on the continuation start signal output to the continuation address control section 107. When the data channel reception carrier detection signal CD2 is turned off, the write start signal output from the write start circuit 201 is turned off. In addition, the address match detection circuit 20
2 detects the match between the addresses of the write address control unit 105 and the successive address control unit 107, and at the time when the address match detection circuit 202 detects the match between the successive address and the final write address, the transmission request circuit 204
turns off the transmission request signal RS3 that had been output until then,
The continuation start circuit 203 is instructed to stop the continuation.

Next, the operation of the DC branching device shown in FIGS. 1 and 2 will be described in detail using the block diagram of the data communication system shown in FIG. 4 and the timing chart shown in FIG. 3.

First, when a polling signal is sent from the communication control device 2 to the data terminal device 9 using the polling/selecting method, the modem device 3, the transmission line 12, the AC branching device 4, the transmission line 5, the DC branching device 6, modem device 7,
Data terminal device 9 via transmission line 15 and modem device 8
transmitted to.

As a result, the data terminal device 9 and the like respond as shown in FIG.

That is, as shown in the timing chart of FIG.
When the transmission request signal R3I output from the data terminal device 9 is turned on, the modulation/demodulation device 8 outputs the carrier signal CR1 to the modulation/demodulation device 7 via the transmission line 15. As a result, the modulation/demodulation device 8 turns on the transmission enable signal C81 after the elapse of time Tc51 and outputs it to the data terminal device 9.

As a result, the data terminal device 9 receives the transmission data signal SD.
Start sending.

On the other hand, the modulation/demodulation device 7 that has received the carrier signal CRI from the transmission line 15 receives the transmission request signal R3 from the data terminal device 9.
After Tcd2 hours after sending I, the data channel reception carrier detection signal CD2 is turned on. Therefore, the data channel received carrier detection signal CD2 inputted to the DC branching device 6 is inputted to the transmission request control section 108 via the carrier received data OR circuit 109 as described above, and turns on the transmission request signal R83. , and output to the modem 5. At the same time, the transmission data signal SD received from the modulation/demodulation device 7 is input to the jitter absorption circuit 101, and after absorbing the jitter included in the transmission data signal, it is stored in the storage section 103 via the transmission data OR circuit 102. As described above, the write start signal is output from the transmission request control unit 108 to the write address control unit 105, and the write address control unit 105 receives the transmission data signal S.
The address for storing D is counted and outputted to the storage section 103, and the transmission data signal SD is sequentially written into the storage section 103 in response to a write signal from the write timing control section 104.

Next, the DC branching device 6 receives the transmission enable signal CS3 from the modulation/demodulation device 5 after TCS3 time elapses after turning on the transmission request signal R33 and outputting it to the modulation/demodulation device M5.

As a result, as described above, the transmission request control unit 108 of the DC branching device 6 outputs a continuous start signal to the continuous address control unit 107, and the read address control unit 107 starts writing to the storage unit 103. Successive output timing control unit 10 sequentially outputs successive address signals from the address.
The transmission data signal SD is read out from the storage section 103 by the read signal from 6. The transmission data signal SD read out in this manner is transmitted to the communication control device 2 via the modem 5, the transmission line 13, the AC branching device 4, the transmission line 12, and the modem M3.

When the data terminal device 9 finishes transmitting the transmission data signal SD, it turns off the transmission request signal R3I.

As a result, the data channel reception carrier detection signal CD2 outputted from the modulation/demodulation device 7 is turned off, the transmission request signal RS3 outputted from the transmission request control section 108 in the DC branching device 6 is turned off, and the write address control Part 10
5 and the write timing control unit 104 to stop the write address and write signal, thereby causing the storage unit 10
Writing to 3 stops. The read address control unit 107 and the successive timing control unit 106 output write addresses and read signals up to the final write address, and the memory unit 103
The transmission data SD is read out from the transmitter and transmitted to the modulation/demodulation device 5 as a transmission data signal SD.

Therefore, the time Tc5l from when the transmission request signal R3I turns on until the transmission ready signal C3I turns on is Tc5l<
(TcD2+Tc53), the data from the data terminal device 9 can be transmitted normally, and (Tcd2+Tc5
3) Since the transmission data signal SD can be transmitted with only a time delay, an efficient system can be constructed.

Furthermore, since it is not necessary to set the above-mentioned condition of Tc5l≧(Tcd2+Tc53), the effort of setting the time Tc51 can be saved.

In the above embodiment, the case where the present invention is applied to the DC branching device 6 has been described, but the present invention is not limited to this. A similar effect can be obtained by providing . That is, the modulation/demodulation device 5 receives a transmission request signal transmitted from the data terminal device side, and thereby transmits a transmission enable signal to the data terminal device side;
After the first means transmits the clear-to-send signal, the second means stores the data transmitted from the data terminal device side, and receives the clear-to-send signal from the modem 3 on the central station side, and This is realized by providing a third means for reading data from the second means and transmitting the data to the central office side after the preparation for transmission is completed.

Furthermore, a similar effect can be obtained by providing a data communication connection device having a function of accumulating transmission data signals between the modulation/demodulation device 5 and the DC branching device 6.

〔Effect of the invention〕

According to the data communication connection device and data communication system of the present invention, storage of the transmission data signal is started by the data channel reception carrier detection signal received from the data terminal device side, and readout is started by the transmission enable signal from the central office side. This eliminates the need to set a sufficiently long time period after the transmission request signal is output from the data terminal equipment until the transmission clear signal is output from the modem connected to the data terminal equipment. It is possible to normally transmit all data transmitted from the terminal device to the central processing unit.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a DC branching device which is an embodiment of the data communication connection device of the present invention, FIG. 2 is a block diagram showing a specific example of the transmission request control section shown in FIG. 1, and FIG. 4 is a time chart for explaining the operation when the DC branching device shown in FIGS. 1 and 2 is applied to the data communication system shown in FIG. FIG. 5 is a block diagram showing one configuration example of a data communication system performed through a modulation/demodulation device, and a time chart for explaining the operation of the data communication system shown in FIG. 4. 1... Central processing unit, 2... Communication control device, 3, 5
゜7.8.10...Modulation/demodulation device, 6...DC branching device, 9.11...Data terminal device, 103...Storage unit, 104...Write timing control unit, 105...・
Write address control unit, 106... Read timing control unit, 107... Successive address control unit, 108... Transmission request control unit, 201... Write start circuit, 202...
・Address-number construction circuit, 203...reading start circuit,
204...Transmission request circuit. Agent Patent Attorney Masami Akimoto

Claims (1)

[Claims] 1. A central office side line termination device that communicates data with the central office side via a transmission line, and a data terminal device that communicates data with a data terminal device side via a transmission line. A data communication connection device placed between the data terminal equipment and the data terminal equipment stores the data sent via the data terminal equipment, reads the stored data, and sends it to the central office equipment. What is claimed is: 1. A data communication connection device characterized by comprising means for: 2. A line termination device on the central office side that communicates data with the central office side via a transmission line, and a line termination device on the data terminal device side that communicates data with the data terminal device side via a transmission line. In the data communication connection device disposed between the devices, at least a first means for receiving a data channel reception carrier detection signal transmitted from the line termination device on the data terminal device side; a second means for transmitting a transmission request signal to the central office side line terminating device by receiving the signal; a fourth means for receiving a send clear signal from the central office side line terminating device; and a fourth means for receiving a send clear signal from the central office side line terminating device; A fifth device that reads data from and sends it to the central office side line termination device.
1. A data communication connection device comprising: means. 3. A central office, a central office side line termination device that communicates data via a transmission line between the central office, and a data terminal device;
A data terminal device side line termination device that communicates data with the data terminal device via a transmission line, and a data communication connection device placed between the central office side line termination device and the data terminal device side line termination device. In the data communication system, the data terminal device-side line termination device transmits a signal based on the transmission request to the data communication connection device in response to a transmission request from the data terminal device, and After a period of time, a first transmission enable signal is sent to the data terminal device, the data terminal device starts transmitting data in response to the first transmission enable signal, and the data communication connecting device responds to the signal based on the transmission request. In response, a transmission request signal is sent to the line terminating device on the central office side, and the line terminating device on the central office side responds with a second transmission enable signal, thereby establishing the connection for data communication. The apparatus includes a storage means, starts data transmission from the data terminal device to the connection device before the second transmission clear signal and stores the data in the storage means, and the connection means receives the second transmission clearance signal. A data communication system characterized in that the data is read from the storage means and transmitted to the central office side line termination device in response to the above. 4. In a data communication system that includes a central office side line termination device that communicates data with the central office side via a transmission line, and that mutually exchanges data between the data terminal equipment side and the central office side, The station-side line termination device receives the transmission request signal transmitted from the data terminal device side, and includes a first means for transmitting a transmission enable signal to the data terminal side; After transmission, there is a second means for storing the data transmitted from the data terminal device side, and after completion of transmission preparation in the central office side line termination device, the data is read from the second means and sent to the central office side. A data communication system characterized by comprising a third means for transmitting.