JPH0715597A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To reduce communication time and communication cost by sending a signal while shifting down the signal to a V.27ter signal at once when level fluctuation due to fading takes place in a line. CONSTITUTION:When a TCF signal is received by using a public line, a level detector 13 provided to a receiver side Rx of a MODEM 9 detects a level. When the line is used to send an FTT, the presence of detected level fluctuation is sent to a sender side facsimile equipment and when the line state at the time of transmission of FTT is effected by the level fluctuation, the signal is shifted down and the V.27ter signal is used for the signal to be sent next. Thus, the signal is shifted down at once to the V.27ter signal without shifting down step by step in the line having deterioration due to level fluctuation such as fading to reduce communication time and to decrease communication cost in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile machine, and more particularly, to a CCITT (Inte
rnational Telegraph and Telephone Consultative Com
mittee) Recommendation T.M. The present invention can be applied to a G3 facsimile apparatus that performs a transmission control procedure (protocol) based on 30. Especially, in the case of a line that is deteriorated with a level change such as fading, the line is not downshifted one by one, but once. To V. The present invention relates to a facsimile apparatus that can downshift to a 27ter signal to shorten communication time.

[0002]

2. Description of the Related Art Conventionally, the delay (d
For example, a facsimile machine which puts in an equalizer at elay time has been reported in Japanese Patent Laid-Open No. 61-56659, and here, a facsimile machine which sends / receives facsimile information via a plurality of transmission lines. , At least one equalizing means for compensating for the transmission characteristic distortion of these transmission lines, a means for measuring the time until the response signal is returned after sending the command signal, and a predetermined value corresponding to the measured time. By configuring so as to have a means for activating one of the equalizing means, the characteristic of the transmission line is identified according to the distance, and the equalizer corresponding to the distance is automatically selected, In the case of an international line, good facsimile information can be sent / received with a simple configuration without downshifting the transmission speed. It has the advantage that.

Conventionally, the CCI has been used by using a public network line.
TT Recommendation T. In the G3 facsimile apparatus which performs the transmission control procedure based on 30, the transmission line is checked automatically before the image information by the TCF (Training Check) signal because it is affected by various deterioration conditions on the line during communication. The method of downshifting is adopted.

[0004]

However, in the conventional facsimile apparatus as described above, when the line in use causes level fluctuation such as fading, V. 27
Since the ter signal is sequentially downshifted, the communication time required during that time becomes very long, and there is a problem that the communication cost increases. The modulation method is D
Since the signal using AM is modulated in the phase direction and the amplitude direction, an error is likely to occur in such a line and it is not suitable for communication. In the case of a 27ter signal that is modulated only in the phase direction, an error is relatively unlikely to occur and is suitable for communication.

Therefore, the present invention does not shift down one level at a time when V.V. Communication time can be shortened by downshifting to 27ter signal,
It is an object of the present invention to provide a facsimile device that can reduce communication costs.

[0006]

The invention according to claim 1 is
CCITT (International Tele
graph and Telephone Consultative Committee) Recommendation T. In a G3 facsimile apparatus which performs a transmission control procedure based on 30, a level detection unit provided on the receiving side of a modem and a level detection unit when receiving a TCF (Training Check) signal, and In the case of a line transmitting an FTT (Failure to Train), whether or not the detected level is changed is transmitted to the transmitting side facsimile, and the line state at the time of transmitting the FTT is caused by the level change. If the signal is downshifted, the signal to be transmitted next is downshifted to V. It is characterized by having a transmission control unit which performs a 27ter signal.

According to a second aspect of the present invention, in the first aspect of the present invention, a route different from the route entering the receiving modem is provided in front of the receiving modem, and the received signal has a high frequency and a low frequency in the voice band. A band-pass filter set to a frequency and a cable equalizer setting for extracting the frequency component by the band-pass filter, measuring the level by the level detection unit, and determining the set value of the cable equalizer based on the difference between the two levels. And a value setting unit.

According to a third aspect of the present invention, in the invention according to the second aspect, the TCF at the beginning of communication of the function of the second aspect is used.
If the signal is V. 17 signals, V.I. 33 signals and V.I. It is characterized in that it has a control unit which performs only when there are 29 signals. According to a fourth aspect of the present invention, in addition to the first to third aspects of the invention, the TSI (Transm
When the itting Subscriber Identification) signal is transmitted, after the communication of the function result operated in the above claims 1 to 3 is completed, a storage unit that stores the function result together with the contents of the TSI, and the transmission at the time of the next communication When the TSI signal is transmitted to the facsimile on the side, a judging unit for checking the inside of the storage unit and the same TSI signal as the result judged by the judging unit are stored in the storage unit. 3 is set, and the contents stored in the storage unit are set by the first TCF.

[0009]

First, the operation of the invention according to claim 1 will be described.
In the conventional facsimile apparatus, when the line in use causes level fluctuation such as fading, V. There is a problem that the communication time required during that time is extremely long because the signals are sequentially downshifted to the 27ter signal.

Therefore, according to the invention of claim 1, CCITT Recommendation T.264 is used by using a public network line. In a G3 facsimile apparatus that performs a transmission control procedure based on 30, the level detection unit provided on the receiving side of the modem detects a level when receiving a TCF signal, and when the line transmits FTT,
Whether or not the detected level has fluctuated is transmitted to the transmitting side facsimile, and when the line condition at the time of transmitting the FTT is due to the level fluctuation, shift down and then transmit. The signal is transmitted to the V. 27
It is configured so that the ter signal can be used.

Therefore, in the case of a line in which deterioration accompanied by level fluctuations such as fading occurs, V.V. Since it is possible to shift down to the 27ter signal, V. Immediately. 27ter
It is possible to prevent unnecessary downshifting by dropping the signal. Therefore, the communication time can be shortened and the communication cost can be reduced.

Next, the operation of the invention described in claims 2 and 3 will be described. Regarding the attenuation distortion, a means to solve it by inserting a cable equalizer has been considered. According to this means, it is possible to steadily raise and compensate the high frequency attenuation characteristic. However, conventionally, it is often the serviceman's judgment to select whether or not to insert this cable equalizer.

Therefore, in the present invention as set forth in claims 2 and 3, a path different from the path entering the reception modem is provided in front of the reception modem, and the received signal is set to a low frequency band and a high frequency band within the voice band. Take out the frequency component with a pass filter, measure the level with the level detector, and
The set value of the cable equalizer is determined by the cable equalizer set value setting means based on the difference between the two levels, and the above-mentioned function is controlled by the control unit when the TCF signal at the beginning of the communication is V.
17 signals, V.I. 33 signals and V.I. It is configured so that it can be performed only when there are 29 signals. Therefore, the cable equalizer that automatically compensates the attenuation distortion can be appropriately set without changing the transmission control procedure, and thus the downshift due to the attenuation distortion can be efficiently prevented.

Next, the operation of the invention according to claim 4 will be described. In the case where the same line is used for communication, the line deterioration condition often remains almost unchanged. Therefore, in the invention of claim 4, the setting of claims 1 to 3 is performed by confirming the partner device by TSI. Instead, unnecessary operation is omitted. Therefore, in the invention according to claim 4, when the TSI signal is transmitted from the transmission facsimile, after the communication of the function result operated in the above claims 1 to 3, the function result is stored together with the contents of the TSI in the storage unit. When the TSI signal is transmitted to the transmitting facsimile during the next communication, the determination unit checks the inside of the storage unit, and the same TSI signal as the determination result by the determination unit is stored in the storage unit. In this case, the contents stored in the storage unit can be set in the first TCF by the setting unit without performing the setting of the first to third aspects. Therefore, when communication is performed on the same line, unnecessary operation can be omitted without performing the setting of claims 1 to 3 each time, so that stable communication can be performed and the cable equalizer can be used from the beginning. Can be set.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a facsimile apparatus according to each embodiment of the present invention. The facsimile apparatus in the illustrated example is based on CCITT recommendation T.264. This is a case where the present invention is applied to a G3 facsimile apparatus which performs a transmission control procedure based on 30. As shown in FIG. 1, the facsimile apparatus according to this embodiment includes a system control unit 1, an encoding / decoding unit 2, a line buffer memory 3, an operation display unit 4, an operation port 5, a scanner 6, a plotter. 7, TSI storage memory 8, modem 9, switches 10a-10b, and equalizers 11a-11c.
, Bandpass filter 12, level detector 13, 2
The line / line conversion unit 14 and the NCU 15 are included.

Here, the system control unit 1 is composed of a microcomputer that controls each unit to perform a predetermined operation of the facsimile apparatus, and the encoding / decoding unit 2 compresses the image information to be transmitted by data compression. At the same time, the received image information is decoded to reproduce the original image information, the operation display unit 4 displays operation guidance, etc., and the operation port 5
According to the guidance displayed on the operation display unit 4, the facsimile apparatus is made to execute various operations for executing a predetermined transmission / reception process.

Next, the scanner 6 reads out image information of a predetermined resolution from the original image, the plotter 7 records the image information on recording paper, the TSI storage memory 8 stores the contents of TSI, and the modem 9 The image information encoded by the encoding / decoding unit 2 is modulated and the received image information is demodulated, and various procedure signals in the transmission control procedure are transmitted.
The bandpass filter 12 sets a reception signal when a path different from the path entering the reception modem 9 is provided in front of the reception modem 9, and sets the reception signal to a low frequency and a high frequency within the voice band, and extracts the frequency component thereof. The level detector 13 measures the level of the frequency component extracted by the bandpass filter 12, and the NCU 15 performs network control for connecting the facsimile machine to the public telephone network. (Embodiment 1) In this embodiment (Claim 1), the characteristic part according to Claim 1 will be specifically described by using the facsimile apparatus of FIG.

FIG. 2 is a diagram showing a communication procedure flow in a normal time and a communication procedure flow in a standard flow (claim 1) according to the first embodiment of the present invention, and FIG. 2B shows a procedure flow, and FIG. 2B shows a communication procedure flow in the standard flow. FIG. 3 is a flowchart showing a basic operation flow according to the first embodiment of the present invention. In this embodiment, first, after the line is closed, the receiving facsimile Rx transmits the CED and NSF (CSI) .DIS signals, and the transmitting facsimile Tx receiving this transmits N.
Sends SS (TSI) / DCS signal. At this time, if the flow is non-standard, the sending facsimile Tx is N
Only send SS.

After this, the sending facsimile Tx is TC
F signal is transmitted, and at this time, the receiving side facsimile Rx
With counting the number of errors, to measure the level by the level detector 13 (process P ₁ ~P _3). Next, when the number of errors is smaller than a certain value n (process P ₄ ), the CFR
Is transmitted (process P ₅ ), and image information is received. If the number of errors is equal to or more than the constant value n (process P ₄ ), the signal to be transmitted is changed according to the next judgment condition.

Next, a threshold at a level is set (for example, 3 dB), the number of times the change occurs is counted, and when the level fluctuation number is 2 or more (process P
_{In 6} ), it is judged that an error has occurred due to the level fluctuation, and when it does not depend on the level fluctuation (process P ₆ ),
The facsimile Rx on the receiving side transmits a normal FTT (process P ₇ ). On the other hand, when it is due to the level change (process P ₆ ), the receiving facsimile Rx sends V. The bit is set and transmitted so that only the 27ter modem 9 is held (process P ₈ ).

At the time of non-standard flow, for example, FTT
The number of termination flags of
After notifying x, the sending facsimile Tx sends the next NS
S, DCS-TCF to V.S. Set to 27ter and send. As described above, in this embodiment, the level is detected by the level detector 13 provided on the receiving side of the modem 9 when the TCF signal is received using the public network line, and the level is detected when the FTT is sent out. Whether or not the level has fluctuated is transmitted to the transmitting facsimile, and the FT
When the line condition at the time of transmitting T is due to level fluctuation, the signal to be downshifted and transmitted next is V.T.
It is configured so that it can be performed with a 27ter signal.

For this reason, in the case of a line in which deterioration accompanied by level fluctuations such as fading occurs, the V.V. Since it is possible to shift down to the 27ter signal, V. Immediately. 27ter
It is possible to prevent unnecessary downshifting by dropping the signal. Therefore, the communication time can be shortened and the communication cost can be reduced. (Embodiment 2) In this embodiment (Claims 2 and 3), the characteristic portion according to Claims 2 and 3 will be specifically described by using the facsimile apparatus of FIG.

FIG. 4 is a flowchart showing a basic operation flow according to the second embodiment of the present invention. In this embodiment, T
CF is received, and the first DCS-TCF receives the V.V. 33, V.I.
17, V.I. Only when there are 29 signals, the level detector 13 measures the level of only that frequency with the two band pass filters 12 in the low band (for example, 800 Hz) and the high band (for example, 2500 Hz) between the TCFs (processes P _{11 to} P). ₁₄ ).

Next, the number of errors is counted (process P ₁₅ ) and when the number of errors is smaller than a certain value n (process P ₁₅ ).
₁₆ ) transmits the CFR (process P ₁₇ ) and receives image information. If the number of errors is a certain value n or more (process P ₁₆ )
Is low level a [dB] and high level b.
If it is [dB], it is determined by b-a whether or not the cable equalizer is inserted (process P ₁₈ ). For example, b-
When a = 6, the cable equalizer 11c is set. Then, the subsequent communication is performed as usual (process P ₁₉ ).

As described above, in this embodiment, the receiving modem 9
Is provided in front of the receiving modem 9, a path different from the path entering the receiving modem 9 is provided, the frequency component of the received signal is taken out by the band pass filter 13 set to the low frequency and the high frequency in the voice band, and the level detector 13 The level is measured, and the set values of the cable equalizers 11a to 11c are determined by the difference between the two levels. 17 signals, V.I. 33 signals and V.I. It is configured so that it can be performed only when there are 29 signals. Therefore, the cable equalizers 11a to 11c for automatically compensating for the attenuation distortion can be appropriately set without changing the transmission control procedure, so that the downshift due to the attenuation distortion can be efficiently prevented. (Embodiment 3) In this embodiment (Claim 4), the characteristic part according to Claim 4 will be specifically described by using the facsimile apparatus of FIG.

FIG. 5 is a flow chart showing the basic operation flow according to the third embodiment of the present invention. In this embodiment, after the line is closed, CED and NSF (CSI) DIS are transmitted from the receiving facsimile Rx, and then TSS is transmitted to the NSS (TSI) DCS transmitted by the transmitting facsimile Tx.
When the SI signal is attached, this content is stored in the TSI storage memory 8. Then, the above operation is performed, and T
Along with the contents of SI, the V. 27t
or the equalizer type set in the second embodiment (claims 2 and 3) is stored. This may be during communication or after communication after setting is completed.

Then, after the line is closed by the next communication, it is sent.
TSI is added to the signal of the receiving facsimile Tx
At times, the contents of the TSI storage memory 8 are checked (processing
Reason P _{twenty one}, P_{twenty two}). At this time, the same TSI contents are written in the TSI.
When not in the memory 8 (Process P_{twenty three}) In Examples 1 and 2.
(Claims 1 to 3) is set (Process P_{twenty five}), Of TSI
Store the set contents with the contents in the TSI storage memory 8.
(Process P₂₆).

On the other hand, when the same TSI is in the TSI storage memory 8 (process P ₂₃ ), the V.V.
Reading the type of bit and cable equalizers 11 a to 11 c that it has set the V.27ter, setting the cable equalizer 11 a to 11 c (process P _24), receives a TCF of transmitting facsimile Tx, V. Only when it is set to 27ter and when the TCF must return FTT due to error occurrence, V. The bit is set and transmitted so that only the 27ter modem 9 is held.

As described above, in this embodiment, when the TSI signal is transmitted from the transmission facsimile, after the communication of the function results of the operations of the first and second embodiments (claims 1 to 3) is completed, the function is terminated. The result is stored in the TSI storage memory 8 together with the contents of the TSI, and when the TSI signal is transmitted to the transmitting facsimile at the next communication, the inside of the TSI storage memory 8 is checked, and the same TSI signal as the result of this determination is the TSI signal. When it is in the storage memory 8, the contents stored in the TSI storage memory 8 can be set by the first TCF without performing the settings of the first and second embodiments (claims 1 to 3). is doing. Therefore, when communication is performed on the same line, useless operations can be omitted without performing the settings of the first and second embodiments (claims 1 to 3) each time, and stable communication can be performed. Others, cable equalizer 11
a to 11c can be set from the beginning.

[0030]

According to the present invention, in the case of a line in which deterioration accompanied by level fluctuations such as fading occurs, the V.V. There is an effect that the communication time can be shortened by shifting down to the 27ter signal, and the communication cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a communication procedure flow in a normal time and a communication procedure flow in a standard flow according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a basic operation flow according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a basic operation flow according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing a basic operation flow according to the third embodiment of the present invention.

[Explanation of symbols]

 1 System control unit 2 Encoding / decoding unit 3 Line buffer memory 4 Operation display unit 5 Operation port 6 Scanner 7 Plotter 8 TSI storage memory 9 Modem 10a, 10b switch 11a, 11b, 11c Equalizer 12 Bandpass filter 13 Level detector 14 2 wire to 4 wire converter 15 NCU

Claims (4)

[Claims] 1. A CCITT (Intern) using a public network line.
ational Telegraph and TelephoneConsultative Commit
tee) Recommendation T. In a G3 facsimile apparatus that performs a transmission control procedure based on 30, the level detection unit provided on the receiving side of the modem and a TCF (Training Check)
When a signal is received, the level detection unit detects the level, and when the line is an FTT (Failure to Train) transmission line, it transmits to the transmitting side facsimile whether or not the detected level is a change. , And when the line condition at the time of transmitting the FTT is due to level fluctuation, the signal to be downshifted and transmitted next is V.V. A facsimile machine having a transmission control unit for performing 27ter signals. 2. A bandpass filter in which a path different from a path entering the receiving modem is provided in front of the receiving modem, and the received signal is set to a low frequency and a high frequency in a voice band,
The frequency component is taken out by the bandpass filter,
The facsimile apparatus according to claim 1, further comprising a cable equalizer set value setting unit that measures the level by the level detection unit and determines a set value of the cable equalizer based on a difference between the two levels. 3. The function according to claim 2, wherein the TCF signal at the beginning of communication is V.V. 17 signals, V.I. 33 signals and V.I. 3. The facsimile apparatus according to claim 2, further comprising a control unit for performing only 29 signals. 4. A TSI (Transmit
ting Subscriber Identification) signal is transmitted, after the communication of the function result operated in the above claims 1 to 3 is completed, a storage unit for storing the function result together with the contents of the TSI, and the transmission at the time of the next communication. T on the side facsimile
When the SI signal is transmitted, the determination unit that checks the inside of the storage unit and the T that is the same as the result determined by the determination unit
4. When the SI signal is stored in the storage unit, the above-mentioned 1 to 3
The contents stored in the storage unit without setting
4. The facsimile apparatus according to claim 1, further comprising a setting unit configured by CF.