JPH09261444A - Facsimile signal transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly transmit an additional number also in a facsimile main service by releasing the operation of an echo suppressor at the time of detecting a transmission destination signal being the additional number. SOLUTION: A voice coding part 1 consists of an echo suppressor 10 preventing the leakage of a signal by disconnecting the signal which is outputted from a decoding part 2 and creeps to an input terminal as an echo by way of an output terminal 200 and the 4-wire and 2-wire conversion circuit of an exchange, and a PB detector 11, etc., detecting a push button dial signal inputted from the exchange by way of the input terminal 100. The output signal being the PB detecting result of the PB detector 11 at the voice coding part 1 controls the switch 25 and the delay circuit 24 in the voice decoding part 2 and when a PB signal is detected, resets a delay circuit 24 at the same time of switching the switch 25 to the side of the voice decoder and simultaneously stops the operation of the echo suppresor. Thereby the signal inputted from the input terminal 100 is inputted to a voice coder 12 by way of a delay circuit 15 as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile signal transmitter, and more particularly to a device for transmitting a transfer destination signal indicating a transfer destination number to which the facsimile signal should be transferred, in addition to the facsimile signal.

[0002]

2. Description of the Related Art Conventionally, when a telephone band signal is digitized and transmitted, compression coding is performed in order to improve the line efficiency. At this time, if bit-rate voice coding is performed, sufficient quality is obtained when the input is a voice signal, but distortion is increased due to high-efficiency voice coding when a FAX signal is input. However, there is a problem that a normal FAX signal cannot be transmitted due to deterioration of the quality of the reproduced signal. In order to deal with this problem, various methods have been conventionally proposed.

For example, JP-A-64-49470,
JP-A-5-37674, JP-A-64-89652
Japanese Laid-Open Patent Publication No. 2004-242242 detects whether an input signal is a facsimile signal or a voice signal, demodulates the signal in the case of a facsimile signal by a demodulator, and transmits it, and in the case of a voice signal, a voice encoding method such as ADPCM. By 16 [kbit
/ S] has been proposed.

Further, Japanese Patent Laid-Open No. 4-349735 discloses a discrimination circuit for discriminating whether an input signal is a voice signal or a facsimile signal, and a plurality of voice encoders. In the case of a signal, 32 [kbit /
[s] ADPCM encoder performs encoding, and in the case of a facsimile signal, 64 [kbit / s] PCM
A technique has been proposed in which a voice / FAX signal is efficiently ATM-transmitted on the same line by executing encoding by an encoder. Then, the problem of the echo occurring at that time is solved by performing the echo canceller control according to the types of the discrimination circuit and the voice encoder.

However, according to the conventional techniques described in these publications, the process is executed when the input signal is a voice signal.
2 [kbit / s] or 16 [kbit / s] high-efficiency voice coding processing time, and 64 [kbit / s] voice with little quality deterioration or demodulation processing of a facsimile signal executed when the input is a facsimile signal Since the processing time for encoding is different, it is necessary to insert a delay circuit on the encoding or decoding side to absorb the difference in processing time.

Usually, a certain processing time required for encoding / decoding when the input signal is a voice signal requires several milliseconds to several tens of milliseconds (the processing time varies depending on which encoding method is adopted). However, the processing time is uniform when the encoding method is determined), but it takes several hundreds of milliseconds to demodulate / modulate and output the facsimile signal from detection.

If such encoding processing is switched and used according to the input signal without using this delay circuit, the last part of the facsimile signal modulated and output on the decoding side will be deleted, and the normal facsimile operation will be performed. There is a problem that transmission is not possible.

FIG. 5 shows the operation timing of the switch for performing such switching. As shown in the figure, the data input to the decoding unit is from the voice coded data to the FA
At time A when the X coded data is changed, the output of the FAX data detector changes from the low level to the high level. However, as a result of demodulation processing being performed in the decoding unit,
The FAX demodulated signal is delayed by the time T and is output after the time B.

Similarly, the output signal changes from the FAX demodulated signal to the reproduced voice signal after the time when the FAX encoded data changes to the voice encoded data. Therefore, the last part of the facsimile signal output after decoding is cut off, and normal facsimile transmission cannot be performed.

Further, in Japanese Unexamined Patent Publication No. 4-349735, the stable operation of the echo canceller is guaranteed, and the output of the encoding side is stopped during the fax modulation signal output on the decoding side (the cells are not made into cells in ATM transmission). Therefore, an echo canceller control method has been proposed for improving the efficiency of the line. However, when this echo canceller control system is used in combination with the delay circuit described above, the fax mail transfer destination selection number (PB number) is set in the protocol between FAX terminals, as in the fax mail service.
Is input in the application, PB (Push B
There is a drawback that the (uton) signal cannot be normally accumulated.

The reason for this is as follows. That is, when the conventional technique is applied to the processing procedure of the FAX mail service as shown in FIG. 6, the echo canceller is controlled based on the control signal delayed by the delay circuit. Therefore, the DIS (Digital I / F) output from the FAX terminal on the receiving and storing side after the call connection is completed.
The 2'nd dial signal (PB signal) that is input to the encoding side immediately after the transmission of the identification signal is not normally input to the speech encoder and cannot be stored normally.

The 2'nd dial signal in FIG. 6 is the operator on the originating FAX terminal side (that is, the person trying to store and register the fax information in the fax mail terminal).
However, the 2'nd dial is input after listening to the DIS signal from the recipient's fax mail terminal. Therefore, the PB signal may be input to the encoding side during transmission of the DIS signal. In such a case, a normal PB signal is not input to the voice encoder by the operation of the echo canceller regardless of the presence or absence of the delay circuit described above, and therefore the 2'nd dial signal cannot be transmitted.

In the figure, "DCS" is Dig.
ital Command Signal, "TCF"
Is a Training Check Flag, "CF
"R" stands for Confirmation to Receive
e, "PIX" is Picture, "EOP" is End
of Procedure, “MCF” is Messa
ge Confirmation, “DCN” is Dis
It is connect.

[0014]

In the facsimile mail service, a general facsimile terminal transmits image information to a terminal for facsimile mail having a facsimile information storage function, stores the image information, and then stores it in a designated destination. It is a service that transfers faxes. Such services are becoming widespread for the purpose of transmitting faxes in the corporate communication network at night when traffic is light. Here, in the fax storage terminal, the facsimile number (image information) is given to the delivery destination (transfer destination) telephone number (2'nd
Dial signal; also called additional dial).

In this facsimile mail service, a facsimile communication protocol (ITU-TT.3) is once provided.
After entering 0), it has a sequence for designating the destination by the additional dial of the PB signal. When the conventional voice encoding / decoding device is used for the transmission line of the facsimile mail service, the PB signal of the additional dial in the sequence of FIG. 6 is treated as the voice encoding process.

However, in the configuration in which the delay circuit described above generates a constant delay time, since the switching timing from the fax encoding / decoding processing to the voice encoding / decoding processing is delayed, the echo suppressor on the encoding side causes the PB. The input of the signal to the speech coding means is suppressed. Therefore, there is a problem that a normal additional dial cannot be transmitted. Therefore, the conventional technique cannot be applied to the facsimile mail service in which the PB signal of the additional dial is inserted into the facsimile protocol.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and its object is to apply to a facsimile mail service in which a PB signal of an additional dial is inserted in a facsimile protocol. It is an object of the present invention to provide a facsimile signal transmitting device that can be used.

[0018]

A facsimile signal transmitting apparatus according to the present invention is a facsimile signal transmitting apparatus for transmitting a transfer destination signal indicating a transfer destination number to which the facsimile signal should be transferred, in addition to the facsimile signal. A signal suppressing unit provided in a transmission side transmission line for transmitting a transfer destination signal and blocking a signal from the reception side transmission line to the transmission side transmission line to prevent signal leakage, and in response to the input of the transfer destination signal. And a control unit for canceling the signal cutoff by the signal suppressing unit.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention is as follows.

When the signal indicating the transfer destination number to which the facsimile signal is to be transferred is detected, the signal cutoff by the echo suppressor for cutting off the signal to the transmitting side and preventing the signal leakage is released. As a result, the operation of the echo suppressor can be stopped when the additional dial in the facsimile mail service is detected, and the PB signal of the additional dial can be sent normally.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a first embodiment of a facsimile signal transmitting apparatus according to the present invention. In the figure, the facsimile signal transmitting apparatus according to the present embodiment has an input terminal 100 and an output terminal 20 for inputting / outputting with a switchboard.
Input terminal 1 for input / output between 0 and digital transmission line
01 and an output terminal 201.

The speech encoding unit 1 intercepts the signal output from the decoding unit 2 as an echo passing through the output terminal 200 and the four-wire / two-wire conversion circuit (hybrid) of the exchange to the input terminal 100, and leaks the signal. An echo suppressor 10 for preventing the noise, a PB detector 11 for detecting a push button dial signal input from the exchange through the input terminal 100, and a high-efficiency voice encoder for encoding a voice signal at a low bit rate. 12, a FAX demodulator 13 for detecting and demodulating a FAX signal, a switcher 14, and a voice encoder 1
The delay circuit 15 delays the signal input to the echo suppressor 10 and the delay circuit 15 that delays the signal input to the echo suppressor 10 for a predetermined time.

The role of the echo suppressor 10 will be described with reference to FIG. As shown in the figure, the input terminal 100 of the encoding unit 1 is output from the output terminal 200 of the decoding unit 2 via the hybrid 300 in the exchange 30.
Then, the signal leaks as indicated by arrow Y. Therefore, the echo suppressor 10 temporarily shuts off the transmission side transmission line in order to prevent signal leakage from the decoding unit 2, that is, the signal reception side transmission line to the encoding unit 1, that is, the signal transmission side transmission line. -ing

When the signal is not cut off, the signal from the facsimile terminal (FAX) 400 can be applied to the input terminal 100, which can be encoded and transmitted to the player side.

The input terminal 100 is connected to the PB detector 11 and also to the echo suppressor 1 via the delay circuit 16.
Connected to 0. The output of the echo suppressor 10 is
In addition to being input to the FAX demodulator 13, it is also input to the high-efficiency speech encoder 12 via the delay circuit 15.

The high-efficiency voice encoder 12 encodes the voice signal input via the echo suppressor 10 and the delay circuit 15 into low bit rate digital data, and outputs it to the switch 14.

Further, the FAX demodulator 13 detects whether the signal input via the echo suppressor 10 is a modulated signal from the FAX terminal, controls the switching unit 14 according to the detection result, and at the same time, inputs the FAX. After the modulated signal from the terminal is demodulated and converted into digital data, the switch 14
Output to

The switching device 14 is the F from the FAX demodulator 13.
According to the AX signal detection result, either one of the low bit rate speech coded data output from the speech coder 12 and the demodulated digital data output from the FAX demodulator 13 is selected, and is output via the output terminal 101. And output to the digital transmission line.

On the other hand, the decoding unit 2 receives the data signal received from the digital transmission line through the input terminal 201 from the FA terminal.
FAX for discriminating between X-coded data and voice-coded data
A data detector 21 and a voice decoder 23 for decoding and outputting reproduced voice when the received data is voice coded data,
A FAX modulator 22 that modulates and outputs received data according to a detection result of the FAX data detector 21, and a delay circuit 24 that delays the detection result of the FAX data detector 21 by a predetermined time.
And a switch 25 for selecting and outputting either the output of the voice decoder 23 or the output of the FAX modulator 22 according to the output of the delay circuit 24.

The input terminal 201 is a FAX data detector 2
1, a FAX modulator 22, and a voice decoder 23. The audio signal decoded by the audio decoder 23 is output to the output terminal 200 through the switch 25. Similarly, the output of the FAX modulator 22 is also output to the output terminal 200 as a FAX modulation signal through the switch 25.

The FAX data detector 21 discriminates whether the received data is encoded voice data or FAX encoded data, and F is detected only when the received data is FAX encoded data.
The AX modulator 22 is operated, and at the same time, a control signal indicating that FAX data is being detected is output to the delay circuit 24. The control signal during FAX data detection controls the switch 25 and the echo suppressor 10 in the encoding unit 1 after being delayed for a certain time in the delay circuit 24.

The switch 25 receives the output control signal from the delay circuit 24, and after a certain time elapses from the FAX data reception, the FA switch receives the FA data.
The output signal from the X modulator 22 is selected, and in other cases, the output of the speech decoding unit 23 is selected.

The output control signal of the delay circuit 24 controls the echo suppressor 10, and while the decoding side is outputting the FAX modulated signal, the echo is output by the voice encoder 12 and the FA.
It is controlled so that it is not input to the X demodulator 13.

The output signal which is the PB detection result of the PB detector 11 in the voice encoding unit 1 controls the switch 25 and the delay circuit 24 of the voice decoding unit 2, and switches when the PB signal is detected. The switching circuit 25 is switched to the voice decoding side and the delay circuit 24 is reset at the same time, and at the same time, the operation of the echo suppressor 10 is stopped. As a result, the input terminal 100
The signal input from the above is directly input to the speech encoder 12 via the delay circuit 15.

The switch 25 is connected to the PB as described above.
The output signal of the detector 11 and the output signal of the delay circuit 24 are used as control inputs. In this case, it is assumed that the switch 25 is controlled by the result of the logical sum of both output signals.

In addition, the delay circuit 24 has the F
While delaying the output signal of the AX data detector 21,
It is reset by the output signal of the PB detector 11. This operation is shown in a time chart in FIG.

That is, the output signal of the delay circuit 24 changes from the low level to the high level with a delay of the time t from the input signal thereof. Further, at the timing when the PB detector 11 is input, the output signal of the delay circuit 24 is reset and changes from the high level to the low level ().

The delay circuit 24 includes, for example, a well-known RS.
Type flip-flop is used. Then, the output signal of the FAX data detector 21 may be input to the set input side via a delay line that delays by the time t.
Further, the output signal of the PB detector 11 may be directly input to the reset input side.

Next, the operation of the apparatus of this embodiment will be described in detail with reference to FIG.

In the sequence of the fax mail service shown in FIG. 6, when this apparatus is installed in the transmission line section, the following operation is performed.

First, a dial signal (PB signal) for call connection is input to the input terminal 100 of the voice encoding / decoding device 1 installed on the transmitting FAX terminal side. This PB signal is input to the echo suppressor 10 via the delay circuit 16. The output of the echo suppressor 10 is input to the audio encoder 12 via the delay circuit 15, encoded into a low bit rate digital signal, and then output from the output terminal 101 to the digital transmission line through the switcher 14. It

Since the echo suppressor 10 has no signal output from the output terminal 200 on the decoding side, the signal input to the terminal 100 is directly input to the delay circuit 1.
It is input to the voice encoder 12 via 5. Also, FA
The input signal to the X demodulator 13 is V.X. from the FAX terminal.
21, V.I. 27ter, V.A. 29, V.I. 17, V. 33
Protocol signal (modulated signal) between facsimile terminals such as
Therefore, the detection result of the FAX signal becomes undetected, and the switcher 14 selects and outputs the output of the voice encoder 12.

On the other hand, the voice encoding / decoding device 2 installed on the opposite incoming fax mail terminal side has an input terminal 201.
The digital data from the transmitting side is received via the voice decoder 23, the PB signal is reproduced by the voice decoder 23, and output through the output terminal 200 via the switch 25. This establishes a call between the incoming fax mail terminal and the outgoing fax terminal.

Here, the FAX data detector 21 is in the FAX undetected state because the received data is not the FAX coded data, and the switch 25 passing through the delay circuit 24 selectively outputs the voice decoder 23. There is.

After the call is established, the terminating FAX mail terminal sends V. By outputting a DIS signal which is a 21-modulated signal, it operates to prompt the calling side to send out a 2'nd dial signal.

Here, the DIS signal is a preamble signal, NSS [Non-Standard Facili].
ties Set-up] signal, NSF [Non-St]
signal and signals], CSI
[Called Station Identifier
signal] signal. In the present audio encoding / decoding device, these V. Even if the modulation signal of 21 is input, all operate in the same manner as the DIS signal.
The S signal will be described as a representative.

The DIS signal from the incoming FAX mail terminal is input from the input terminal 100 of the voice encoding / decoding device 1 installed on the incoming FAX mail terminal side, and input to the FAX demodulator 13 via the echo suppressor 10. To be done.
The FAX demodulator 13 switches the switch 14 to the output of the FAX demodulator 13 by detecting the DIS signal, and at the same time demodulates the DIS signal and converts it into digital data.
It is output from the output terminal 101 as FAX encoded data.

In the voice encoding / decoding device 2 installed on the side of the opposing transmitting FAX terminal, the DIS signal encoded into the input digital signal is received, and the FAX modulator 22 is activated by the FAX data detector 21. Then, the DIS signal is modulated based on the received data. The FAX detection signal output from the FAX data detector 21 is output to the delay circuit 2
4 is input to the switch 25, and the switch 25 is FA
It operates to select the output of the X modulator 22. At the same time, the FAX detection signal is input to the echo suppressor 10.
The echo suppressor 10 forcibly cuts off the path from the input terminal 100 to the FAX demodulator 13 and the delay circuit 15 so that the echo is not input to the voice encoder 12 and the FAX demodulator 13.

Here, the delay circuit 24 is the FAX modulator 2.
2 is a FAX modulation processing delay T _FD from when FAX encoded data is received until it is output as a modulated signal, and a time T _VD (the time required for the voice decoder 23 to decode the received data and obtain a reproduced signal). Time (T) of the difference from the speech decoding processing delay
_It shall be designed to delay the signal by the same time as _FD- T _VD ).

The caller hears the modulated DIS signal 2 '.
Input the nd dial signal from the originating fax terminal. 2 '
The nd dial signal (PB signal) is input to the echo suppressor 10 and the PB detector 11 through the input terminal 100 of the voice encoding / decoding device installed on the transmitting side. The PB detector 11 detects the 2'nd dial signal and resets the switch 25 on the decoding side to forcibly control and selectively output the output of the voice decoder 23. At the same time, the delay circuit 2
4 is reset, the operation of the echo suppressor 10 is stopped, and the FAX demodulator 13 from the input terminal 100 is stopped.
And a signal path to the delay circuit 15 is established.

As a result, the PB signal which is the input 2'nd dial signal is input to the voice encoder 12 via the echo suppressor 10 and the delay circuit 15 and is transmitted in the same manner as in the case of call connection. It is stored in the FAX mail terminal on the receiving side.

Here, the delay circuit 15 is the FAX demodulator 1
Time T _FE (FAX demodulation processing delay) required to demodulate the FAX signal in FIG. 3 and output as FAX encoded data, and for the voice encoder 12 to encode and output the input signal to low bit rate digital data. The time difference between the required time T _VE (speech coding processing delay) (T _FE −
It is designed to delay the signal by the same time as T _VE ). Further, the delay circuit 16 is designed to delay the signal by the same time as the time until the PB detector 11 detects the PB signal.

All the subsequent sequences in FIG. 6 are protocol signals and image information modulation signals based on modulation signals between FAX terminals, and are digitally transmitted as FAX encoded data by the FAX demodulator 13 and FAX modulator 22. To be done. The operation of this device at this time is the same as the operation in the transmission of the DIS signal.

As described above, in the present apparatus, the coding side constantly monitors whether or not the input signal is the modulated signal from the FAX terminal, and when the result of the monitoring is the FAX signal, It is possible to output the FAX detection signal to the switch and simultaneously output the demodulation data. If the result of monitoring is a PB signal, a PB detection signal is output to the switch and the delay circuit on the decoding side. Thus, the switch can select the voice coded output for the transmission line when the FAX detection signal is not detected and the FAX demodulated output when the FAX detection signal is detected.

On the other hand, on the decoding side, the line data is constantly monitored, and while the FAX data is being received, the FAX detection signal is output to the switching unit via the delay circuit, and the switching unit switches to the FA
While receiving X data, select the output of FAX modulator
If it is other than data, select the output of the speech decoder. The echo suppressor cuts off the path on the encoding side so that the echo is not input to the encoding side while the decoding side is outputting the FAX modulated signal.

When the data received from the line on the decoding side is switched from FAX coded data to voice coded data, a delay circuit delays a fixed time from the data switching point, and then the switch Is switched from the FAX modulation output to the voice decoding output. When the PB signal is detected, the delay circuit is reset to switch the output of the switch from the FAX modulation output to the voice decoding output without delay time.

With this configuration, the echo suppressor can be controlled according to the PB signal detection result, and the echo suppressor suppression / interruption operation can be stopped at the time when the additional dial in the facsimile mail service is detected. Therefore, the PB signal of the additional dial can be normally input to the voice encoder, and all the stored sequence signals of the facsimile mail can be normally encoded and transmitted.

Next, the second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

The second embodiment shown in FIG. 4 is the first
1 is a modification of the embodiment of FIG. 1 and the same parts as in FIG. This device is similar to that shown in FIG.
This is a configuration in which 4 is deleted.

Here, in this embodiment, the FA in FIG.
The FAX demodulation processing delay time of the X demodulator and the speech coding processing delay time of the speech encoder are equal, and the FAX modulation processing delay time of the FAX modulator and the speech decoding processing delay time of the speech decoder. Are equivalent when and are equal, and the operation is also similar to the operation in FIG. In this example, the delay circuits 15 and 24 are unnecessary, the amount of hardware is small,
The cost can be reduced.

As described above, according to the first and second embodiments, the FA found in the facsimile mail service is used.
Even in the sequence in which the 2'nd dial signal is input in the protocol sequence between the X terminals, the normal 2
Since the'nd dial signal can be transmitted, this device can be used even in the transmission line (transmission device) of the facsimile mail, and the line efficiency can be improved.

[0063]

As described above, according to the present invention, the additional number can be correctly transmitted even in the facsimile mail service by canceling the operation of the echo suppressor when the transfer destination signal which is the additional number is detected. There is an effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a facsimile signal transmitting apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a role of an echo suppressor 10 in FIG.

FIG. 3 is a time chart showing an operation of a delay circuit 24 in FIG.

FIG. 4 is a block diagram showing a configuration of a facsimile signal transmitting apparatus according to a second embodiment of the present invention.

FIG. 5 is a time chart showing the operation of the conventional device.

FIG. 6 is a FAX storage sequence diagram of a facsimile mail service.

[Explanation of symbols]

 1 Encoding Section 2 Decoding Section 10 Echo Suppressor 11 PB Detector 12 Speech Encoding Section 13 FAX Demodulator 14, 25 Switching Switch 15, 16, 24 Delay Circuit 22 FAX Modulator 23 Speech Decoder

Claims (4)

[Claims] 1. A facsimile signal transmitting apparatus for transmitting a transfer destination signal indicating a transfer destination number to which the facsimile signal is to be transferred, in addition to the facsimile signal, and is provided in a transmission side transmission line for transmitting the transfer destination signal. Signal suppressing means for blocking a signal from the receiving side transmission path to the transmitting side transmission path to prevent signal leakage; and control means for releasing the signal blocking by the signal suppressing means in response to the input of the transfer destination signal. A facsimile signal transmitting apparatus comprising: 2. The transfer destination signal is a dial signal, and the control means includes a detection means for detecting the dial signal, and in response to the detection, cancels the signal cutoff by the signal suppressing means. The facsimile signal transmitting apparatus according to claim 1. 3. The signal delay means for delaying the signal input to the signal suppressing means for a time corresponding to the detection processing time of the detecting means, further comprising:
The described facsimile signal transmitter. 4. The signal suppressing means according to claim 1, wherein only a digital signal of the signals from the receiving side transmission line to the transmitting side transmission line is blocked to prevent signal leakage. Facsimile signal transmitting apparatus according to any one of the above.