JP4169702B2 - Facsimile machine - Google Patents

Description

  The present invention relates to a facsimile apparatus, and more particularly to an ITU-T recommendation V.1, which switches a data transmission mode when a silence state of a received voice signal is detected. The present invention relates to a facsimile apparatus provided with a modem conforming to 34.

In general, a facsimile apparatus transmits a voice signal in which data such as image data is modulated through a telephone line on the transmission side, and acquires data by demodulating the voice signal received through the telephone line on the reception side. . Basic communication control such as modulation / demodulation of data is performed by a modem.
Here, it is a modem provided in the facsimile machine, which is an ITU-T recommendation V.30. 34, the data transmission mode is switched when a silence state of the received voice signal is detected. That is, on the transmission side, a group of image data is transmitted under the communication conditions of the primary channel, which is a data transmission mode in which the data transmission speed is set to a high speed, and after the transmission of the group of image data is completed, the data transmission speed is Is switched to the control channel, which is a data transmission mode set to low speed, and a silent signal is transmitted for a certain period of time (ie, a silent state in which nothing is transmitted). On the other hand, on the receiving side, image data is received under the communication condition of the primary channel, which is a high-speed reception mode, and when a silent state is detected in the received audio signal, the data transmission mode is switched to the control channel.
The primary channel is a transmission mode in which image data is transmitted at high speed. A group of image data is divided into a plurality of image frames (frame data), which are sequentially transmitted, and the last image frame in the group of image data. “RTC” that is identification information indicating the end of transmission of the image data is transmitted.
The control channel is a transmission mode in which control data other than image data is transmitted at a low speed (reliably), and a group of image data can be normally received from the image data receiving side to the transmitting side. And a request for retransmission of image data when normal reception is not possible.
On the transmission side, after transmitting “RTC” on the primary channel, a silence signal is output for a certain period of time (that is, data transmission is not performed), and then the control channel is shifted to. On the other hand, on the receiving side, when a silent state for a certain period of time is detected in the primary channel, the receiving channel shifts to the control channel.
Such ITU-T recommendation V.I. Although modems conforming to the standard No. 34 are widely used, they do not necessarily have a sufficient function for dealing with a communication abnormality, and it is desirable to provide a separate function for dealing with a communication abnormality.
For example, Japanese Patent Application Laid-Open No. H10-228561 discloses that a modem can reduce the transmission rate in the primary channel when an image frame is not received even after a predetermined time has passed since the transition to the primary channel. Thereby, more reliable image data can be received. In this patent document 1, ITU-T recommendation V.I. 34 is also described in detail.
JP 2002-185744 A

However, in the receiving modem, if the silence state of the received audio signal is not normally detected due to noise or the like, the image data is retransmitted after a time-out communication error occurs after a relatively long time. Therefore, there is a problem that it takes a long time to transmit image data.
In addition, the technique disclosed in Patent Document 1 does not show a coping function when a silent state cannot be detected normally.
Accordingly, the present invention has been made in view of the above circumstances, and its object is, for example, ITU-T Recommendation V. Even if the silent state is not detected normally, the modem that switches the data transmission mode when the silent state of the received voice signal is detected, such as a modem that complies with the standard 34, is communicated due to a time-over. It is an object of the present invention to provide a facsimile apparatus that can continue data transmission as soon as possible without waiting for an error.

In order to achieve the above object, according to the present invention, when a voice signal in which data is modulated is received through a telephone line and the data transmission mode is the first mode for transmitting image data, the silence state of the voice signal is In a facsimile apparatus having a modem that switches a data transmission mode to a second mode for transmitting other control data when detected, the voice signal from the telephone line is input to the modem or a silent signal is transmitted. Silence switching means for switching whether to input, and silence switching control means for performing switching control of the silence switching means based on data received by the modem , wherein the silence switching control means is in the first mode. The silence state is detected within a predetermined time after the identification information indicating the end of the transmission of the image data is detected from the data received by the modem. The silent switching means if not issued is constituted as a facsimile apparatus comprising switching to silent signal side.
As a result, even if the silence state is not normally detected due to noise or the like, if it is determined that the data transmission mode needs to be switched based on the received data, the silence state is forcibly created and the data transmission mode is forced. Can be switched automatically. As a result, it is possible to continue data transmission as soon as possible without using a conventional modem and waiting for a communication error to occur due to a time-over even if a silent state is not normally detected.
More specifically, it is conceivable that the silence switching means comprises a switch for switching connection or disconnection of the input path of the voice signal from the telephone line to the modem .

Further, according to the present invention, each time transmission of a group of image data ends, a silent state is provided to switch from the first mode (image data transmission mode) to the second mode (control data transmission mode). This is effective when a communication procedure is adopted .
In addition, as a typical modem shown above, ITU-T recommendation V. There is a modem conforming to 34.

  According to the present invention, in a facsimile apparatus equipped with a modem that switches a data transmission mode when a silence state of a received voice signal is detected, the voice signal from the telephone line is input to the modem or a silence signal is transmitted. Silence switching means for switching whether to input and silence switching control means for controlling switching of the silence switching means based on the data received by the modem, so that a silence state is not normally detected due to noise or the like However, if necessary, a silent state can be forcibly created and the data transmission mode can be forcibly switched. As a result, it is possible to continue data transmission as soon as possible without using a conventional modem and waiting for a communication error to occur due to a time-over even if a silent state is not normally detected.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is a block diagram showing a schematic configuration of the facsimile apparatus X according to the embodiment of the present invention, FIG. 2 is a flowchart showing a switching procedure of a route switch of a received voice signal in the facsimile apparatus X, and FIG. 3 is an ITU- T Recommendation V. 34 is a diagram schematically showing a data string of transmission data by a FAX modem conforming to 34. FIG.

First, the configuration of the facsimile machine X according to the embodiment of the present invention will be described with reference to the block diagram of FIG.
As shown in FIG. 1, the facsimile machine X includes a CPU 1, a RAM 2, a reading device 3, a printing device 4, a storage device 5, a FAX modem 6, and a HYB 7 (transmission path / reception path separating unit). Components are connected via a system bus 8.
The CPU 1 executes various control processes for the entire facsimile apparatus X by executing a control program stored in a ROM (not shown), and the RAM 2 is used as a work area when the CPU 1 executes the control program. Storage means.
The reading device 3 reads an image from a manuscript with various optical systems. The image processing device 4 encodes and compresses image data of the manuscript image read by the reading device 3, and a telephone line network (public line). Network) and image data (compressed and encoded image data) received from the other party via the FAX modem 7 is decoded and expanded.
The printing device 4 forms an image on recording paper based on the image data decoded and expanded by the reading device 3 or the image data of the original read by the reading device 3.
The storage device 6 is a storage means such as a hard disk for temporarily storing image data received from the other party or image data of a document read by the reading device 3 and various data such as a destination telephone number. .
The HYB 8 is provided between the FAX modem 7 and the public line network 10 (telephone line), and transmits a transmission signal (voice signal) from the output terminal of the FAX modem 7 to the public line network 10 as well as the public line. The voice signal transmitted from the network 10 is transmitted to the input end side of the FAX modem 7.

The FAX modem 7 is an ITU-T recommendation V.30. 34, a primary channel (an example of the first mode) which is a high-speed data transmission mode for transmitting image data, and a low-speed (reliable) data transmission mode for transmitting other control data. Switch to a certain control channel.
The FAX modem 7 modulates various data such as image data of a manuscript at the time of data transmission and transmits it as an audio signal through the public network 10 (telephone line). At the time of data reception, the FAX modem 7 modulates an audio signal obtained by modulating the image data. Is transmitted through the public network 10 (telephone line), and the received audio signal is demodulated to obtain transmission data such as image data as digital data.
Further, the FAX modem 7 is an ITU-T recommendation V.30. 34, when the silence state of the received audio signal is detected under the communication condition of the primary channel (an example of the first mode) that is the transmission mode of the image data, as described above, Switching to a control channel (an example of the second mode) which is a transmission mode for transmitting other control data.

FIG. 3 shows the ITU-T recommendation V.3. 34 schematically shows a data string of transmission data transmitted by the FAX modem 7 conforming to No.34.
Here, FIG. 3A shows transmission data of the transmission-side FAX modem 7, FIG. 3B shows reception data of the reception-side FAX modem 7, and FIG. 3C shows transmission data of the reception-side FAX modem 7. Represents. The right direction toward FIG. 3 is the time axis direction.
As shown in FIG. 3A, the FAX modem 7 on the transmission side has a plurality of image frames (in the figure, “image frames”) in which a group of image data is divided in the primary channel state. Are transmitted in sequence, and “RTC”, which is identification information indicating the end of transmission of the image data, is transmitted following the end of transmission of the last image frame in the group of image data. Then, after transmitting “RTC”, a silence signal is output for a certain period of time (that is, data transmission is not performed), and then, the process proceeds to the control channel.
On the other hand, the reception-side FAX modem 7 shifts to the control channel when a silent state for a certain time is detected in the state of the primary channel.
In the control channel state, a response request “PPS.EOP” is transmitted from the transmission side to the reception side (see FIG. 3A), and when this is received at the reception side (FIG. 3B). )), A response is returned from the reception side to the transmission side. FIG. 3C is an example showing a case where “MCF / PPR” which is a request for retransmission of image data is returned as a response because the image data could not be normally received due to noise or the like.

A feature of the facsimile apparatus X is that a path switch 11 (an example of the silence switching means) for switching whether the FAX modem inputs a voice signal from the public line network 10 (telephone line) or a silence signal is input. It is a point to have. The path switch 11 is a switch for switching whether to connect or disconnect the voice signal input path from the public line network 10 to the FAX modem 7. By switching the path switch 11 to the side that cuts the input path, the FAX modem 7 detects a silent state.
The CPU 1 (an example of the silent switching control means) inputs data received by the FAX modem 7 via the system bus 9 and, based on the received data, inputs to the path switch 11 via the system bus 9. The switching control of the path switch 11 is performed by outputting a switching signal.
In addition to the above, the facsimile machine X includes various devices included in a normal facsimile machine. However, the facsimile machine X does not particularly constitute a feature of the present invention, and thus description thereof is omitted here.

Next, the procedure of switching control of the path switch 11 by the CPU 1 will be described using the flowchart of FIG. In the following, S1, S2,... Represent processing procedure (step) numbers. Although not shown in FIG. 2, when the FAX modem 7 is communicating, the CPU 1 is set to the transmission mode of the data acquired by the FAX modem 7 and the primary channel and the control channel. Information is sequentially input via the system bus 9. The process shown in FIG. 2 is executed only when the FAX modem 7 is in the primary channel state.
In the primary channel (first mode) state, the CPU 1 determines whether or not “RTC”, which is identification information indicating the end of transmission of image data, is detected from the data received by the FAX modem 7 (S1). ”Is detected, a timer built in the CPU 1 is started, and the elapsed time after“ RTC ”detection is started (S2), and then the process proceeds to step S3. If “RTC” is not detected, the process proceeds to step S3.
In step S3, the CPU 1 determines whether or not reception of one frame of image data (one image frame) has been completed based on the received data by the FAX modem 7 in the primary channel (first mode) state. (S3), when the completion of reception of one image frame is detected, the timer is separately activated to start measuring the elapsed time after completion of reception of the image frame (S4), and then the process proceeds to step S5. . If the completion of reception of the image frame is not detected, the process proceeds to step S5 as it is.
Here, whether or not reception of one image frame has been completed is determined by, for example, detecting identification information indicating the end of image frame transmission provided in each image frame.

In step S5, the CPU 1 determines whether or not a silence state is detected from the data received by the FAX modem 7 (S5). If the silence state is detected, both timers (after “RTC” is detected). (S6) and timer after completion of image frame reception) are stopped (S6), and then the process proceeds to S7. If the silent state is not detected, the process proceeds to S7 as it is.
Here, the presence / absence of the silent state is detected when the silent state is not acquired in the FAX modem 7 for a certain period of time (for example, about 70 ms to 100 ms).
In step S7, it is checked whether any one of the timer time after detection of “RTC” or the timer time after completion of image frame reception has passed a preset monitoring time (predetermined time). S7).
Here, when the CPU 1 determines that the monitoring time (for example, about 3 to 4 seconds) has elapsed (that is, an image for one frame within a predetermined time after detecting “RTC”). When the silent state is not detected within a predetermined time after the completion of data reception), the path switch 11 is set to the signal path disconnecting side (that is, to the silent signal side) for a certain period of time (silent in the FAX modem 7). Time required for detecting the state (for example, about 70 ms to 100 ms) After switching, switch switching processing for returning to the signal path connection state is executed (S8), and the timer is stopped (S9) After executing the abnormal process (S10: discarding the data received halfway, etc.), the process returns to step S1 to repeat the process described above. On the other hand, if it is determined that the monitoring time has not elapsed, the process returns to step S1 and the above-described processing is repeated.

Based on the data received by the FAX modem 7 in the primary channel (first mode) state by the above-described processing of the CPU 1 (S1 to S10), one frame of image data (one image frame) is stored. The silence state is not detected within a predetermined time after reception completion is detected, or the silence state is not detected within a predetermined time after detecting “RTC” (identification information) indicating the end of transmission of image data, When the communication abnormality is detected, the path switch 11 (silence switching means) can be switched to the silence signal side (path disconnect side).
As a result, even if a silent state is not normally detected by the FAX modem 7 due to noise or the like, the FAX modem 7 detects the silent state that is forcibly created by its original function and uses it as a control channel. Then, a response indicating that the image data has been normally received and a request for resending the image data are made. As a result, data transmission can be continued immediately without waiting for the occurrence of a communication error due to time-out.

  The present invention can be applied to a facsimile machine.

1 is a block diagram illustrating a schematic configuration of a facsimile machine X according to an embodiment of the present invention. 4 is a flowchart showing a switching procedure of a path switch of a received voice signal in the facsimile apparatus X. ITU-T Recommendation V. The figure which represented typically the data string of the transmission data by the FAX modem based on 34. FIG.

Explanation of symbols

1 ... CPU
2 ... RAM
3 ... Reading device 4 ... Image processing device 5 ... Printing device 6 ... Storage device 7 ... FAX modem 8 ... HYB (transmission path / reception path separating unit)
9 ... System bus 10 ... Public line network (telephone line)
11: Route switches S1, S2,... Processing procedure (step)

Claims (3)

The audio signal data is modulated received through a telephone line, a transmission mode of the data when the silent state of the audio signal when the transmission mode of the data is the first mode for transmitting the image data is detected Other In a facsimile apparatus having a modem for switching to a second mode for transmitting control data of
Silent switching means for switching whether to input the voice signal from the telephone line or the silent signal to the modem;
Silence switching control means for performing switching control of the silence switching means based on data received by the modem ,
When the silence switching control means detects no silence within a predetermined time after the identification information indicating the end of transmission of image data is detected from the data received by the modem in the first mode, the silence switching means is silent. A facsimile machine that is switched to the signal side .   2. The facsimile apparatus according to claim 1, wherein the silent switching means comprises a switch for switching connection or disconnection of an input path of the voice signal from the telephone line to the modem. The modem is an ITU-T recommendation V.30. The facsimile apparatus according to claim 1 , wherein the facsimile apparatus is a modem conforming to No. 34.

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