JP2003069614A - Data transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the restoration time at the time of dada transfer abnormality in comparison with a conventional device. SOLUTION: In a data transmission device 2, a threshold of the counted number of HEC error signals, which is the condition of output of a resynchronizing trigger signal in an HEL counter part 233. When a reception data signal is received, an HEC error is detected by an HEC detection part 232 at each time of receiving a reception ATM cell, and the resynchronizing trigger signal is outputted when the HEC error exceeds the preliminarily set threshold, and a resynchronous detection part 25 generates a synchronization start signal again based on the resynchronizing trigger signal, and a synchronizing signal from an RX signal is detected again from a switching part 262, and synchronization is started again to restore the normal state in order to obtain the reception data signal from the RX signal, and thus the restoration time at the time of data transfer abnormality is made shorter than that in a conventional device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device, and more particularly to a data transmission device connected to an INS network by a bulk communication system, in which data transfer is abnormal due to a change in delay time between time slots in the INS network. The present invention relates to a bulk communication type data transmission device that detects an error and performs recovery processing thereof.

[0002]

2. Description of the Related Art A conventional data transmission apparatus of this type will be described with reference to the drawings.

FIG. 4 is a block diagram showing an example of a conventional bulk transmission apparatus according to the bulk transmission method connected to the INS network, and FIG. 5 shows a connection sequence in the non-frame mode of the conventional bulk transmission apparatus shown in FIG. 6 and 6 are diagrams showing a disconnection sequence due to a delay shift in the non-frame mode of the conventional bulk transmission device shown in FIG.

4 to 5, this conventional example shows the disclosed contents of Japanese Patent Laid-Open No. 10-303890, and after the connection of all channels is completed, the INS network 103 is set for each channel.
Since the delay amount of each INS signal e when passing through is different, the delay correction is performed for each channel on the receiving side to correct the deviation of the delay amount, and after the delay correction is completed, the terminal device 101 _-1 and Communication is performed between the terminal devices 102 _-2 . Note that, for convenience of explanation, the call is made from the terminal device 101 _-1, but the same applies when the call is made from the terminal device 101 _-2 .

In this frame mode (hereinafter referred to as frame mode method) communication, a frame synchronization signal is added to each channel and the delay of each channel is corrected at any time on the receiving side. Therefore, each channel of the INS network 103 Even if the delay amount changes on the way, there is an advantage that the delay can be corrected at any time, but since the frame including the FAW signal h, FC signal i, etc. at the time of bulk transmission must be added, the use efficiency of the transmission path Has the drawback of being bad.

Therefore, in the case of the connection in the non-frame mode, it is the same as the frame mode except that the delay correction of each channel is performed in the non-frame mode at the time of exchanging the capability information. And in non-frame mode, after delay compensation of each channel, the delay amount of each channel is fixed,
Even after the frame synchronization signal of each channel is removed, the delay amount of each channel is maintained as it is. Then, after the frame synchronization signal for bulk transmission is removed and changed to non-frame, communication is performed between the terminal device 101 _-1 and the terminal device 101 _-2 .

In the communication in the non-frame mode (hereinafter referred to as the non-frame mode method), since communication is performed in the absence of a frame signal, the transmission line can be used efficiently.
If the delay amount of each channel of the INS network 103 changes midway, the delay amount cannot be corrected, and the data signal during communication will be in error. Therefore, when the delay amount of the INS network 103 changes and an error of the data signal occurs, a method of disconnecting the communication at the terminal device and reconnecting can be obtained.

In FIG. 6, when the delay amount changes due to INS during normal communication between the terminal device 101 _-1 and the terminal device 102 _-1 , the terminal device 101 _-1 and the terminal device 101 _-2 are changed.
An error occurs in the communication data with the. In this case, therefore, it issues a disconnection notification to the bulk transmission device 102 _-2 terminal device 101 _-2 to cut each channel between the bulk transmission device 102 _-1 and bulk transmission device 102 _2. After the disconnection of all channels is completed, the bulk transmission apparatus 102 _-1 notifies the terminal apparatus 101 _-1 that all channels have been disconnected. For convenience of explanation, but here the cutting notification is assumed to be notified from the terminal apparatus 101 _-2 cutoff notice from the terminal device 101 _-1 is issued, also it goes without saying that if the same operation is performed.

[0009]

In this conventional example, when the delay amount of the INS network changes and an error occurs in the communication data, the terminal device notifies the disconnection to disconnect the communication and reconnect. However, there is a problem that it takes time to recover from such an abnormal data transfer.

(Object of the Invention) An object of the present invention is to transmit data internally in a bulk communication data transmission device using delay calculation for INS network connection mounted in an ATM multiplexer having an ATM cell in an internal data bus. By using the ATM cell parity bit error detection signal and the received ATM cell HEC detection signal to start / stop resynchronization of the delay calculation, and by instructing the control unit that resynchronization is in progress, It is possible to shorten the recovery time in the event of a data transfer error by starting the resynchronization and detecting the resynchronization to restore the data transfer normally without performing the INS network disconnection instruction / reconnection when the transfer error occurs. It is to provide a data transmission device that can perform.

[0011]

A data transmission device of the present invention is a data transmission / reception data transmission / reception transmission device according to a bulk communication method, which is connected to a data transmission / reception terminal and is connected to a destination data transmission device via an INS network. In the transmission device,
For the received data signal obtained by synchronously receiving the received signal from the other party's data transmission device, ITU-T_I.
432-compliant head error check (hereinafter HEC)
And HEC detection means for generating a resynchronization signal for the received data signal when an HEC error is detected by the HEC detection means, the received data signal synchronously received and the Received data signal generating means for generating a resynchronized received data signal by the resynchronized signal from the received signal after detecting an HEC error, and an ATM cell signal for receiving the synchronously received received data signal and the resynchronized received data signal. And a data converting means for transmitting the HEC error, the counting means for counting the number of the HEC errors for each ATM cell when the HEC error is detected, and the counting means for counting the number of the HEC errors. Generates the resynchronization signal to the resynchronization signal generating means when the number of HEC errors exceeds a preset value. A trigger signal generating means for generating a trigger signal so that the trigger signal generating means, when the trigger signal is generated, resynchronizes until the resynchronizing synchronization signal is detected with respect to the connected terminal. The trigger signal generating means includes a PTY checking means for sending a resynchronization notification signal indicating that the transmission is in progress, and performing a parity (hereinafter, PTY) check for the transmission ATM cell signal of the data transmitted from the terminal. The trigger signal is transmitted on condition that the resynchronization notification signal has not been transmitted and there is no PTY error signal from the PTY check means.

The data transmission apparatus of the present invention is a data transmission apparatus which is connected to a terminal for transmitting and receiving data and which transmits and receives the data according to a bulk communication method with a data transmission apparatus of a partner via an INS network. The transmission device generates an parity (hereinafter referred to as PTY) for the transmission data from the terminal through the interface unit that interfaces with the terminal, and transmits a transmission ATM cell signal and a transmission PTY signal, A control unit having a function of receiving a received ATM cell signal and transmitting it to the terminal, a data conversion unit, and a bulk pattern (hereinafter referred to as B
P) for creating and disassembling P), an INS interface for interfacing with the INS network for transmitting and receiving bulk data, a sync detector for detecting a sync signal via the BP, and a data converter. Of the resynchronization trigger signal, the resynchronization unit sends out a resynchronization start signal to the synchronization detection unit, and the data conversion unit detects a PTY error based on the transmission ATM cell signal and the transmission PTY signal. A PTY detection unit that sends out a PTY error signal, creates a transmission data signal and sends it to the BP unit, and an international standard ITU-T_I. A HEC detection unit that performs a head error check (hereinafter, HEC) compliant with H.432, sends an HEC error signal when an HEC error is detected, and creates the received ATM cell signal and sends it to the control unit.
The error signal is counted, and when the preset value is exceeded, the resynchronization trigger signal is sent to the resynchronization unit.
An EC counter unit, wherein the synchronization detection unit continues to send a synchronization activation signal when detecting the input of the resynchronization activation signal from the resynchronization unit until the detection of the input of the synchronization detection signal from the BP unit, When the input of the synchronization detection signal is detected, the re-synchronization detection signal is sent to the re-synchronization unit, and then the transmission of the synchronization signal is stopped, and when the input of the synchronization detection signal is stopped, the transmission of the re-synchronization detection signal is stopped. However, the resynchronization unit outputs the resynchronization start signal to the synchronization detection unit when detecting the input of the retrigger signal, and until the input of the resynchronization detection signal from the synchronization detection unit is detected, The sending of the resynchronization notification signal for notifying the terminal to the control unit is continued.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram showing an example of a bulk communication system to which a data transmission apparatus according to an embodiment of the present invention is applied.

In FIG. 1, a bulk communication system to which the data transmission device of this embodiment is applied is a DTE 1-1, 1-2 for inputting / outputting data, and a data transmission device 2-connected to DTE 1-1. 1 and a data transmission device 2-2 connected to the DTE 1-2, and the data transmission device 2-
Each of 1 and 2 is configured to perform data communication by the bulk communication system of ATM cells via the INS network 3.

The data transmission devices 2-1 and 2-2 are
Resynchronization of delay operation is started / stopped in each inside by using the transmission ATM cell parity bit error detection signal and the reception ATM cell HEC detection signal, and also connected to DET1-1 or 1-2 during resynchronization. By instructing the control unit that resynchronization is in progress, data transfer is normal by starting resynchronization and detecting resynchronization without instructing disconnection / reconnection of the INS network 3 when data transfer is abnormal. The system is designed to shorten the recovery time in the event of a data transfer error compared to the conventional system by recovering to.

FIG. 2 is a block diagram showing a data transmission device according to an embodiment of the present invention.

In FIG. 2, a data transmission device 2 of the present embodiment shows a representative of the data transmission devices 2-1 and 2-2 shown in FIG. 1, and DTE 1-1 or 1-2 (the representative is 1). ), And the DT I / F unit 21 and the DT
Connects to the EI / F unit 21 to notify the resynchronization notification signal and the receiving AT
Transmission AT with M cell signal and call completion signal as input signals
A control unit 224 including a PTY sending unit 221 which internally outputs a transmission PTY signal, using an M cell signal and a transmission PTY signal, a threshold setting signal, and a call instruction signal as output signals;
A transmission ATM cell signal and a transmission PTY signal, a reception data signal, a threshold setting signal, and a resynchronization notification signal are used as input signals,
The reception ATM cell signal, the transmission data signal, and the resynchronization trigger signal are used as output signals, and the transmission ATM cell signal and the transmission PTY signal are used as input signals internally, and the transmission data signal and
A PTY detection unit 231 that outputs a PTY error signal,
An HEC detector 232 that receives a received data signal as an input signal and outputs an HEC error signal, and a PTY error signal and an HE
HEC with C error signal, threshold setting signal and resynchronization notification signal as input signals and resynchronization trigger signal as output signal
A data conversion unit 23 including a counter unit 233, a resynchronization trigger signal, a resynchronization detection signal as an input signal, and a resynchronization unit 24 having a resynchronization notification signal and a resynchronization start signal as output signals, and a call origination A synchronization detection unit 25 that uses an instruction signal, a resynchronization activation signal, a synchronization detection signal, and a confirmation signal as input signals, and uses a call completion signal, a resynchronization detection signal, a synchronization activation signal, and a call signal as output signals, and a transmission data signal. , RX signal and synchronous activation signal as input signals, received data signal, TX signal and synchronization detection signal as output signals, and BP section 26 with synchronous activation signal, synchronous transmission signals and transmission data signals as input signals. Switching unit 26 that uses the TX signal as an output signal
1, a synchronization start signal in the BP unit 26, and RX
A switching unit 262 that uses a signal as an input signal and a synchronous reception signal and a received data signal as an output signal; a BP transmission unit 263 that internally outputs a synchronous transmission signal as an output signal by using a synchronous start signal as an input signal; A BP unit 26 including a synchronous start signal and a synchronous reception signal as input signals and a BP detection unit 264 having a synchronous detection signal as an output signal inside the unit 26, a TX signal and a call signal as input signals, and an RX signal and A confirmation signal is used as an output signal, and an INS I / F unit 27 connected to the INS network 3 is provided.

FIG. 3 is a timing chart of main signals inside the device showing the operation of the data transmission device of the present embodiment shown in FIG.

Next, the operation of the data transmission apparatus of this embodiment will be described with reference to FIGS. 1, 2 and 3.

First, as a determination value for the HEC counter section 233 to output the resynchronization trigger signal from the DTE (1-1 or 1-2) connected to bring the data transmission device 2 into the operating state. If the threshold setting value is input in a predetermined format, this threshold setting value is D
It is stored in the HEC counter unit 233 as a threshold value setting signal from the control unit 22 via the TE I / F unit 21.

Next, the operation for transmitting data will be described.

In the present embodiment, in FIG.
Data transmission / reception between DTE1-1 and DTE1-2 will be described.

For example, in the initial state where the DTE 1-1 has not yet made a call, the control unit 22 of the data transmission device 2-1 has not received the call instruction signal, so the synchronization detection unit 25 receives the call from the control unit 22. When the synchronization start signal is turned off, the synchronization start signal, which is an output signal from the synchronization detection unit 25, is output to the switching unit 2.
The TX signal is selected for 61, and the INS I / F unit 2
7 becomes a state in which the transmission data signal can be transmitted, and the switching unit 262 selects the RX signal from the INS I / F unit 27 so that the reception data signal can be received.

Further, the BP transmission section 263 outputs a high fixed signal, the BP detection section 264 is disabled, and the synchronization detection signal which is its output signal outputs a signal in the OFF state.

Next, when the control unit 22 detects via the DTE I / F unit 21 that the DTE 1-2 is in the calling state, it outputs a calling instruction signal, and the synchronization when the calling instruction signal is detected. The detection unit 25 turns on the output of the synchronous start signal.
Then, while this synchronous activation signal is ON, the BP transmitter 2
63, the switching unit 261 selects this synchronous transmission signal as the TX signal synchronous transmission signal, the switching unit 262 selects the RX signal synchronous reception signal from the INS I / F unit 27, and BP The detection unit 264 receives the synchronization reception signal that is enabled and selected, detects the synchronization, and
The output synchronization detection signal is turned on.

Next, the transmission signal from DTE1-1 is DT.
Received by the control unit 22 via the EI / F unit 21 and transmitted A
It is output as a TM cell signal, and the PTY sending unit 221
At, a parity bit is generated and output as a transmission PTY signal.

The transmission ATM cell signal and the transmission PTY signal are subjected to parity calculation in the PTY detection unit 231 of the data conversion unit 23 and output as a transmission data signal if normal, and the switching unit 261 performs synchronous transmission from the BP transmission unit 263. The signal is combined with the signal and output to the INS network 3 via the INS I / F unit 27 as a TX signal.

In the present embodiment, the synchronization detecting section 25 has the DTE I / F section 21 when the DTE 1-1 makes a call.
When the ON of the calling instruction signal from the control unit 22 is detected via the, the calling completion output signal is turned OFF and the control unit 22
The resynchronization start signal from the resynchronization unit 24 is ignored. After that, the call signal to the INS I / F unit 27 is turned on.
After the confirmation signal from the INS I / F unit 27 turns ON,
Turn off the calling signal, turn on the synchronous start signal, and continue to output the synchronous start signal as ON until the ON of the synchronous detection signal is detected. If the synchronous detection signal is turned on, after turning off the synchronous start signal, The call completion signal is turned on and transmitted to the control unit 22.

Further, while the calling instruction signal at the time of receiving the RX signal is OFF, the OF of the resynchronization start signal from the resynchronization unit 24 is set.
When the change from F to ON is detected, the synchronization start signal is turned on.
After being set to N and sent to the switching unit 262, the BP detection unit 264
The sync start signal continues to be output as it is until ON of the sync detection signal is detected, and if the sync detection signal is turned on, the re-sync detection signal is turned on to the re-synchronization unit 24 and then the sync start signal is output. Is turned off, and if the synchronization detection signal is turned off, the resynchronization detection signal is turned off.

Next, the operation for receiving data will be described.

In the present embodiment, in FIG.
A case where data is transmitted from DTE1-2 to DTE1-1 will be described.

The switching unit 262 in the BP unit 26 uses INSI /
When the RX signal from the INS network 3 is received via the F unit 27, the synchronous reception signal is selected from the RX signals, and the BP detection unit 264 detects the synchronization signal based on this synchronous reception signal and outputs the synchronization detection signal. The synchronization detection unit 25 that outputs and receives this synchronization detection signal sends a synchronization activation signal to the switching unit 262,
The switching unit 262 receives the RX signal based on the received synchronization start signal and sends it to the data conversion unit 23 as a received data signal.

The data conversion section 23 includes an HEC detection section 232.
, ITU-1_ for the received data signal received
I. HEC error is detected according to H.432 and HE
If no C error is detected, the received data is the received ATM
The cell signal is sent from the control unit 22 to the DTE 1-1 via the DTE I / F unit 21.

Next, when an abnormality occurs in the received data signal, H
The case where an EC error is detected will be described below.

The HEC detecting section 232 detects the ITU-T_I. When an HEC error is detected according to H.432, an HEC error signal is output.

In the HEC counter section 233 which receives the HEC error signal and counts it, the DET is performed while the PTY error signal from the PTY detection section 231 is OFF.
When the resynchronization notification signal for 1-1 has already been transmitted and is in the ON state, the resynchronization trigger output signal is in the OFF state by continuing the clear state of the HEC counter unit 233, but the PTY error signal is output. When the HEC error signal is detected to be ON while the resynchronization notification signal is also OFF, the HEC counter unit 233 causes the one reception ATM when the HEC error signal continues to be ON.
The counter is incremented for each cell, and the count value is DTE.
When the preset threshold is exceeded from 1-1, the re-trigger signal is turned on and output.

When the counter value is less than the threshold value and the HEC error signal changes from ON to OFF, the HEC error signal is not generated, or the PTY error signal is detected
In the N state, the resynchronization trigger signal is in the OFF state.

When the resynchronization trigger signal is output from the HEC counter section 233, the resynchronization section 24 sends the resynchronization notification signal to the ON state and sends it to the control section 22. After the sending, the resync start signal is sent. To the ON state.

The synchronization detecting section 25 which has detected the ON of the re-synchronization starting signal again sends the synchronization starting signal to the switching section 262, and the BP detecting section 264 receives the synchronization receiving signal again and detects the synchronization again. The signal can be sent to the synchronization detection unit 25, the synchronization start signal can be sent again to the switching unit 262, and the RX signal can be normally received to obtain the reception data signal.

The resynchronization unit 24 continues to output the resynchronization start signal in the ON state until it detects that the detection signal from the synchronization detection unit 25 is ON again, and when the resynchronization detection signal is detected, the resynchronization start signal is started. After the signal is turned off, the resynchronization notification signal is turned off.

As described above, in the data transmission device 2 of the present embodiment, the HEC counter section 233 stores the threshold value of the count number of the HEC error signal as a condition for outputting the resynchronization trigger signal. When a received data signal is received, the HEC detector 232 detects an HEC error each time a received ATM cell is received, and when the HEC error exceeds a preset threshold value, a resynchronization trigger signal is output, and this resynchronization trigger signal is output. Based on the above, the synchronization detection unit 25 again generates the synchronization start signal, detects the synchronization signal from the RX signal again from the switching unit 262, restarts the synchronization, and obtains the reception data signal from the RX signal. By recovering normally as much as possible, the disconnection instruction / reconnection of the INS network is not performed as in the conventional case, so that the recovery time when the data transfer is abnormal can be shortened as compared with the conventional case.

[0043]

As described above, the present invention relates to a data transmission device which is connected to a terminal which transmits and receives data and which transmits and receives data by bulk communication with a data transmission device of a partner via an INS network. For the received data signal obtained by synchronously receiving the received signal from the other party's data transmission device, ITU-T_I. HEC detection means for performing a head error check (hereinafter referred to as HEC) conforming to H.432, and resynchronization signal generation means for generating a resynchronization signal for a received data signal when an HEC error is detected by this HEC detection means. A reception data signal generating means for generating a resynchronization reception data signal by a resynchronization signal, and a reception data signal synchronously received and a resynchronization reception data signal. By providing a data converting means for converting to an ATM cell signal and transmitting it, the data transfer is normal by starting the re-synchronization and detecting the re-synchronization without instructing the INS network disconnection / reconnection at the time of the data transfer abnormality. Since the data is restored to the normal state, there is an effect that the restoration time when the data transfer is abnormal can be shortened as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an example of a bulk communication system to which a data transmission device according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a data transmission device according to an embodiment of the present invention.

FIG. 3 is a timing diagram of internal signals showing the operation of the data transmission device of the present embodiment shown in FIG.

FIG. 4 is a block diagram showing an example of a conventional bulk transmission device according to a bulk transmission system connected to an INS network.

5 is a diagram showing a connection sequence in the non-frame mode of the conventional bulk transmission device shown in FIG.

FIG. 6 is a diagram showing a disconnection sequence due to a delay shift in the non-frame mode of the conventional bulk transmission device shown in FIG.

[Explanation of symbols]

1-1, 1-2 DTE 2,2-1,2-2 data transmission device 3 INS network 21 DTEI / F section 22 Control unit 23 Data converter 24 Resynchronization section 25 Sync Detector 26 BP section 27 INS I / F section 221 PTY sending unit 231 PTY detector 232 HEC detector 233 HEC counter section 261,262 Switching unit 263 BP transmitter H.264 BP detector

Continued front page    F term (reference) 5K030 GA11 HA10 HC02 JA08 JL08                       JT03 KA01 KA14 KA22 LA08                       LA12 MA04 MB01 MD01                 5K034 AA16 EE07 EE13 FF02 HH02                       HH09 HH10 MM01                 5K047 AA01 AA11 BB16 BB17 HH01                       HH12 HH21 HH43 HH57 MM56

Claims (7)

[Claims] 1. A device for connecting to a terminal for data transmission / reception and IN
In a data transmission device that transmits and receives the data by a bulk communication method with a data transmission device of a partner via an S (registered trademark) network, a reception data signal obtained by synchronously receiving a reception signal from the data transmission device of the partner To the international standard ITU-T_I. HEC detection means for performing a head error check (hereinafter referred to as HEC) conforming to H.432, and a resynchronization signal generation means for generating a resynchronization signal for the received data signal when an HEC error is detected by the HEC detection means. Reception data signal generating means for generating a resynchronization reception data signal by the resynchronization signal, the reception data signal being synchronously received, and the reception signal after the HEC error is detected; ATM receiving resynchronized received data signal
A data transmission device, comprising: a data conversion means for converting the cell signal and transmitting the cell signal. 2. The HEC detecting means, when detecting the HEC error, counts the number of the HEC error for each ATM cell, and the counting means presets the number of the HEC error. 2. The data transmission apparatus according to claim 1, further comprising a trigger signal generating means for generating a trigger signal to cause the resynchronization signal generating means to generate the resynchronization signal when the set value is exceeded. 3. When the trigger signal generating unit generates the trigger signal, the resynchronization notification indicating that the resynchronization is in progress is given to the connected terminal until the resynchronization synchronization signal is detected. The data transmission device according to claim 2, wherein a signal is transmitted. 4. Transmission A of data to be transmitted from the terminal
The PTY check means for performing a parity (hereinafter referred to as PTY) check on the TM cell signal is provided, the trigger signal generating means does not send the resynchronization notification signal, and the PTY error signal from the PTY check means. The data transmission device according to claim 3, wherein the trigger signal is transmitted on condition that there is no signal. 5. An IN connecting to a terminal for transmitting and receiving data
In a data transmission device that transmits and receives the data by a bulk communication method with a data transmission device of a partner via an S network, the data transmission device includes an interface unit for interfacing with the terminal, and the interface unit for interfacing with the terminal. A control unit having a function of generating a parity (hereinafter, PTY) for the data transmitted from the terminal, transmitting a transmission ATM cell signal and a transmission PTY signal, receiving a reception ATM cell signal and transmitting the reception ATM cell signal to the terminal; BP that creates and disassembles the data conversion unit and bulk pattern (BP)
Unit, an INS interface unit that interfaces with the INS network to transmit and receive bulk data, a synchronization detection unit that detects a synchronization signal via the BP unit, and a resynchronization trigger signal from the data conversion unit. A resynchronization unit that sends a resynchronization start signal to the synchronization detection unit,
The data conversion unit transmits the transmission ATM cell signal and the transmission P
When a PTY error is detected based on the TY signal, a PTY error signal is sent out and a transmission data signal is created to generate the BP.
And a received data signal from the BP section to the ITU-T_I. A head error check (hereinafter, HEC) conforming to 432 is performed,
When an HEC error is detected, an HEC error signal is sent out, an HEC detection unit that creates the received ATM cell signal and sends it to the control unit, and the resynchronization when the error signal is counted and exceeds a preset value. A HEC counter unit for sending a trigger signal to the resynchronization unit, the data transmission device. 6. The synchronization detection unit, when detecting the input of the resynchronization activation signal from the resynchronization unit, outputs a synchronization activation signal,
It continues sending until the input of the sync detection signal from the BP unit is detected, and when the input of the sync detection signal is detected, the re-sync detection signal is sent to the re-sync unit, and then the sending of the sync signal is stopped. The data transmission device according to claim 5, wherein when the input of the synchronization detection signal is stopped, the sending of the resynchronization detection signal is stopped. 7. The re-synchronization unit outputs the re-synchronization start signal to the synchronization detection unit when detecting the input of the re-trigger signal, and detects the input of the re-synchronization detection signal from the synchronization detection unit. 6. The data transmission apparatus according to claim 5, wherein the control unit continues to send the resynchronization notification signal for notifying the terminal.