JP3250280B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus, and more particularly, to a facsimile apparatus suitable for reliably detecting completion of image information reception.

[0002]

2. Description of the Related Art In a facsimile machine, 9600 b
When the image information is received in the high-speed mode of ps and the reception of the image information is completed, the modem is switched to the FSK mode, that is, the low-speed mode of 300 bps, to receive the post message command. According to the CCITT recommendation, in order to obtain such modem switching timing, RTC data is added as control return information in the normal G3 communication mode at the end of image information, and an RCP frame is added in the ECM communication mode. .

In some cases, data is disturbed by noise on the line, and the control return information cannot be received.
If the control return information cannot be received, the switching timing of the modem cannot be obtained, and the high-speed mode cannot be exited, so that the post-message command which is a low-speed signal cannot be received. As a result, extra protocol time is required, if there is a next page, the interval between pages will be long, and if communication is stopped, the line cannot be disconnected immediately, and the line will be wasted for a while There was a problem.

To cope with such a problem, there has been proposed a facsimile apparatus in which a control signal (command) is forcibly received when a high-speed signal, that is, image information data cannot be detected continuously for a predetermined time (Japanese Patent Application Laid-Open No. HEI 9-163572). 2-157
No. 79).

In the conventional facsimile machine,
When the scheduled time of the carrier disconnection of the high-speed signal is detected, it is determined that the control return signal has been detected.

[0006]

The above-mentioned conventional facsimile machine has the following problems. That is, in the conventional apparatus, the end of the image information reception is detected by monitoring the high-speed signal or the carrier disconnection of the high-speed signal for the scheduled time, so that it takes a long time to make the determination. In addition, simply shortening the determination time may cause erroneous detection. For example, the carrier is switched from the high-speed signal wait state to the control command wait state due to a momentary interruption of the carrier during image information reception. There was a problem that it could not be received.

An object of the present invention is to solve the above problems,
It is an object of the present invention to provide a facsimile apparatus which can reliably detect the end of image information even if it cannot receive control return information and can avoid taking time for an extra protocol procedure.

[0008]

Means for Solving the Problems The above problems are solved,
In order to achieve the above object, the present invention comprises a preamble detecting means for monitoring a preamble reception of a control command, a modem switching means for alternately switching a modem between a high-speed mode and a low-speed mode, and a means for detecting a high-speed carrier disconnection. And the preamble detecting means performs the carrier disconnection detection before
In addition to starting preamble monitoring,
The modem switching means, there is a first feature that is configured to switch the modem from the high-speed mode to the low-speed mode by said modem switching means upon detection of a preamble by said preamble detection means during receiving image information.

[0009]

Further, the second feature of the present invention is that the preamble monitoring operation is started at least after a lapse of a scheduled time from the start of image information reception.

[0011]

According to the present invention having the above features, the preamble monitoring operation is performed during image information reception. Therefore, even when control return information cannot be received, the end of image information can be detected by detecting the preamble. Then, the modem is switched from the high-speed mode to the low-speed mode based on the detection result.

In particular, since it is determined that the silent state set between the end of the image information and the post message command has ended, the risk of erroneous detection can be greatly reduced.

Further, according to the present invention having the second feature, the preamble monitoring operation is not performed during the unstable period of the modem immediately after the start of image information reception, so that the risk of erroneous detection is greatly reduced. it can.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a main block diagram showing the hardware configuration of the facsimile apparatus according to the present invention. In FIG. 1, a reading device 1 reads a document fed from an automatic document feeder (ADF) 2 and converts the document into an electric signal (image information).
The image information is encoded by the encoding / decoding device 3 and then transmitted to a line via a modem 4 and a network control unit (NCU) 5.

The modem 4 has a low-speed mode and a high-speed mode interface. In the low-speed mode, the transmission procedure signal interface V.V. 21. The high-speed mode is the interface for transmitting / receiving image information. 27ter, V.A. 29, V.S. 3
3, V. 17 and so on.

Further, the modem 4 is provided with at least one of a frequency detecting device for detecting a predetermined frequency of an input signal and a device for detecting a flag pattern. NCU5
Controls the transmission of dial signals and the connection to the network.

The image information read by the reading device 1 can be temporarily stored in the image information memory 6, and can be sent out to the line in response to a separately specified transmission instruction. On the other hand, image information received from the outside is decoded by the encoding / decoding device 3 and then recorded by the printing device 7.

The operation / display device 8 includes operation switches for giving an instruction to the facsimile machine by an operator,
And a panel of a liquid crystal display system or the like for displaying an operation state. The ROM 9 stores a program for controlling the entire facsimile machine and a program for controlling the modem 4 and the NCU 5. RAM10
Is a work area used for executing the program.

The CPU 11 includes the ROM 9 and the RAM
In accordance with the program and control data stored in 10 and the instruction input from operation / display device 8, control processing and transmission control procedure processing of the entire facsimile apparatus are executed. The transmission and reception of data between the above components is performed via the system bus 12.

Further, a host computer 13 and a disk device 14 are connected to the facsimile apparatus, and the image information supplied from these can be transmitted to the other station.
Note that the host computer 13 and the disk device 14 are
The connection can be made via an appropriate interface (not shown).

The receiving operation in the facsimile apparatus having the above hardware configuration will be described with reference to a flowchart.

First, a first embodiment of the present invention will be described with reference to the flowcharts of FIGS. In step S1, an incoming call is waited. If an incoming call is detected, the process proceeds to step S2 to send out the non-standard function signal NSF or the digital identification signal DIS. In step S3, the non-standard function setting signal NS
It is determined whether S or the digital command signal DCS has been received.

If the determination in step S3 is negative, the process proceeds to step S7, where it is determined whether the T4 time specified in the CCITT recommendation has elapsed. The process proceeds to step S3 until the time T4 elapses, and proceeds to step S2 if the time T4 elapses.

If the determination in step S3 is affirmative, the process proceeds to step S4, where the training check TCF
It is determined whether or not was successfully received. If the training check TCF has been successfully received, the process proceeds to step S5, where a reception preparation confirmation signal CFR is transmitted. If the training check TCF has not been correctly received, the process proceeds to step S6, where a training failure signal FTT is transmitted, and the process proceeds to step S3.

The above processing, that is, steps S1 to S7 are standard procedures of phases A and B,
This is common to the third embodiment.

In step S8 (FIG. 4), the modem 4 is set to the high-speed mode (9600 bps), and the detecting operation of the preamble detecting device is started. When the preamble detection device is a device that detects the preamble as a tone, the reception frequency is set to 1650 Hz and the detection operation is started. On the other hand, when the preamble detecting device is a device that monitors a pattern of a flag that forms the preamble, the operation of monitoring a scheduled bit that changes when the flag pattern is detected is started.

In step S9, it is determined whether reception of image information has started. If the determination in step S9 is affirmative, the process proceeds to step S10 to determine whether or not image information reception has ended. This determination is made based on whether a control return code RTC has been received in the normal G3 mode, and whether an RCP frame has been received in the ECM communication mode.

If it is determined that the control return code RTC or the RCP frame has not been received and that the reception of the image information has not been completed, the flow advances to step S11 to determine whether or not a preamble has been detected. Preamble detection
As described above, the determination is made based on whether a signal of a predetermined frequency or a predetermined flag pattern is detected.

If the end of image information reception is detected in step S10, or if a preamble is detected in step S11, the process proceeds to step S12, where the modem 4 is set to the low-speed mode, that is, F
The SK mode is set, and the preamble detection operation ends.

In step S13, a post message command is received, and it is determined from the content thereof whether the reception has been completed or whether there is still image information, that is, whether there is a next page. If the reception is completed, the process proceeds to step S14 to execute the phase D and phase E protocol procedures, and ends the communication.

If reception has not been completed yet, step S1
After executing the phase D protocol procedure in step 5, the process proceeds to step S2 (FIG. 3) or S8. Whether to proceed to step S2 or S8 depends on the transmitted post message command. When the message end signal EOM is transmitted as the post message command, the message confirmation signal MCF is received, and then the process proceeds to step S2. When the multi-page signal MPS is transmitted, the message confirmation signal M is transmitted.
After receiving the CF, the process proceeds to step S8.

In the first embodiment, the preamble detecting operation is performed immediately after the start of the image information reception. However, from the viewpoint of preventing erroneous detection, it is preferable to limit the timing of executing the preamble detecting operation. In the second and third embodiments described below, the preamble detection operation is executed when a predetermined condition is satisfied.

The operation of the second embodiment will be described with reference to the flowchart of FIG. In the second embodiment, the preamble detection operation is started on the assumption that a high-speed carrier disconnection is detected. Note that the operation of FIG. 5 is a continuation of FIG.

In step S20, the modem 4 is set to the high-speed mode for receiving image information. In step S21,
It is determined whether the reception of the image information has been started. If the determination in step S21 is affirmative, the process proceeds to step S22 to determine whether or not the image information reception has been completed.

If it is determined that the control return code RTC or the RCP frame has not been received and that the reception of the image information has not been completed, the process proceeds to step S23 to determine whether or not a carrier disconnection has been detected. Here, for example, the presence or absence of carrier disconnection is determined based on whether the carrier of the high-speed signal has dropped for 5 msec.

If the carrier disconnection is detected, step S24
To start the preamble detection operation. In step S25, it is determined whether the reception of the image information has been completed. If it is determined that the image information reception has not been completed, the process proceeds to step S26 to determine whether a preamble has been detected.

In step S26, a preamble is detected, or in step S25, the control return code RTC or RC
If a P frame has been received, step S13 in FIG.
Processing similar to the processing of S15 is performed.

Next, a third embodiment of the present invention will be described with reference to the flowchart of FIG. The operation of FIG. 6 continues from FIG.

In the third embodiment, the detection of the carrier disconnection and the preamble is started after the modem is stabilized. In the third embodiment, it is determined that the reception of the image information has been completed when both the carrier disconnection and the preamble are detected. However, the carrier disconnection is not determined, and the preamble of the preamble is waited until the modem is stabilized. It may be modified to start only the detection operation.

In step S30, the modem 4 is set to high speed and a timer for measuring the time T is started.
As this time T, a time of 1 second or more is set in order to avoid the length of dummy data transmitted at the head of the normal image information.

In step S31, it is determined whether the reception of the image information has been started. If the determination in step S31 is affirmative, the process proceeds to step S32 to determine whether image information reception has been completed. Control return code RTC or RCP
If it is determined that the frame has not been received and the reception of the image information has not been completed, the process proceeds to step S33 to determine whether or not the timer has timed out. If it is time-out, the determination in step S33 becomes affirmative and step S3
Proceed to 4.

Steps S34 to S37 are performed in step S34.
23 to S26, the description is omitted.

Next, essential functions required for the operation of the above embodiment will be described with reference to the block diagram of FIG. 1, the same reference numerals as those in FIG. 2 denote the same or equivalent parts. In the figure, a modem switching section 15 outputs a switching signal CH for switching the modem 4 between a high-speed mode and a low-speed mode. Here, when the switching signal CH is low (L), the modem 4 is switched from high speed to low speed, and the switching signal CH
Is high (H), the modem 4 is configured to switch from low speed to high speed. Switching between high-speed mode and low-speed mode depends on input signals SEL1 and SEL.
2 is determined.

To switch the modem 4 from the low-speed mode to the high-speed mode, the protocol control unit 16 outputs a signal SEL 1 to the modem switching unit 15 when detecting that the procedure of the phase B has been completed. Modem switching unit 15 receives signal SEL.
1, the switching signal CH is set to (H) to switch the modem 4 from the low speed mode to the high speed mode.

On the other hand, the timing (signal SEL2) for switching the modem 4 from the high-speed mode to the low-speed mode upon completion of the reception of the image information is obtained as follows. When detecting the start of image information reception, the image information reception start detection unit 17 outputs a detection signal D1. This detection signal D1 is supplied to the image information reception end detection unit 18 and the switching unit 19
Is supplied to any one of the preamble detection unit 20, the carrier disconnection detection unit 21, and the timer 22 in accordance with the switching position.

When the detection signal D1 is supplied, the image information reception end detection section 18 starts the detection operation and returns to the control return information RT.
Detection signal D2 when C or RCP frame is detected
To the OR gate 23. When the signal D2 is input, the OR gate 23 opens and the signal SEL2 is output. The signal SEL2 causes the modem switching unit 15 to set the switching signal CH to (L) in order to switch the modem 4 from the high-speed mode to the low-speed mode.

When the switching section 19 is switched to the position a, the preamble detecting section 20 starts the preamble detecting operation in response to the signal D1. When the preamble is detected, the detection signal D3 is output, the gate 23 opens, and the signal SEL2 is supplied to the modem switching unit 15. As described above, the signal SEL2 for giving the timing for switching the modem 4 from the high-speed mode to the low-speed mode.
Is output when the signal D2 or D3 is output from the image information reception end detection unit 23 or the preamble detection unit 20.

When the switching unit 19 is switched to the position b, the carrier disconnection detecting unit 21 starts the operation of detecting the carrier disconnection of the high-speed signal, and outputs the signal D4 when the carrier disconnection is detected. The preamble detection unit 20
When the signal D4 is supplied, the detection operation starts in response to the signal D4.

Further, when the switching unit 19 is switched to the position c, the timer 22 is started by the signal D1, and the time-up signal TU is supplied to the carrier disconnection detecting unit 2
1 is supplied. The carrier disconnection detecting section 21 starts the operation of detecting the carrier disconnection of the high-speed signal by using the time-up signal TU as a trigger.

The time-up signal TU of the timer 22 may be directly supplied to the preamble detection unit 20 to perform the preamble detection operation without the condition that the carrier is disconnected.

The timer 22 sets a time of one second or more as a time until the modem 4 is stabilized.
When this time has elapsed, a time-up signal TU is output. The timer 22 is preferably configured to be reset once when the signal D1 is supplied.

[0052]

As apparent from the above description, according to the present invention, the modem can be switched to the low-speed mode when the control return information or the preamble is detected. Therefore, even when the control return information cannot be detected due to noise on the line, the reception of the image information can be recognized by the detection of the preamble, and the control command, that is, the post message command can be received from the first time. As a result, no extra protocol time is required after the image information reception is completed, and the line can be effectively used.

In particular, the end of image information reception is detected when a preamble is detected based on the premise that a carrier break has been detected. Therefore, the end of image information reception is detected by detecting only a carrier break or only a preamble. The reliability of the detection is improved as compared with the case of performing the detection.

Further, according to the second aspect of the present invention, since the preamble is detected after the stable image information can be detected by the modem, erroneous detection of the preamble can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main function of a facsimile machine.

FIG. 2 is a block diagram illustrating a hardware configuration of the facsimile machine.

FIG. 3 is a flowchart showing an operation (1) of the first embodiment.

FIG. 4 is a flowchart showing an operation (part 2) of the first embodiment.

FIG. 5 is a flowchart showing the operation of the second embodiment.

FIG. 6 is a flowchart showing the operation of the third embodiment.

[Explanation of symbols]

4 modem, 5 NCU, 15 modem switching unit,
16: protocol control unit, 17: image information reception detection unit,
18: Image information reception end detection unit, 19: Switching unit, 20: Preamble detection unit, 21: Carrier disconnection detection unit, 22: Timer

Continuation of front page (56) References JP-A-1-272258 (JP, A) JP-A-2-15779 (JP, A) JP-A-1-321775 (JP, A) JP-A-3-211964 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/32

Claims (2)

(57) [Claims] 1. A comprising a preamble detection means for monitoring a preamble reception of control commands, and modem switching means for switching alternately modem high-speed mode and low speed mode, and means for detecting the high speed of the carrier cross the <br/> The preamble detection means is based on carrier disconnection detection.
And the modem switching means switches the modem from the high-speed mode to the low-speed mode by the modem switching means when the preamble detection means detects the preamble during image information reception. Facsimile machine characterized by the following. 2. Monitoring the reception of a preamble of a control command.
Preamble detection means and the modem are alternately switched between a high-speed mode and a low-speed mode
Comprising a modem switching means, a timer means which is started when image information receiving start, the preamble detection unit is configured to start monitoring operation of the preamble, subject to time-up of at least said timer means, said modem switching means , While receiving image information,
When the preamble is detected by the
Modem switching means changes the modem from high-speed mode to low-speed mode.
A facsimile apparatus characterized in that it is configured to switch to a fax mode.