JPH04369169A - Communication speed control method and picture communication equipment - Google Patents

Abstract

PURPOSE:To avoid overflow of a picture information memory without sacrificing the communication speed inadequately in the picture communication equipment employing a low speed printer such as a thermal ink jet printer. CONSTITUTION:A memory management section 108 detects an idle memory capacity of a picture information memory for each reception of one page of picture information. A system control section 111 decides the communication speed for receiving a succeeding page based on the idle memory capacity. A communication control section 104 controls the communication speed for receiving picture information of the succeeding page in response to the result of the decision.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for communicating image information via a line, and more particularly to an image communication device configured to store received image information in a memory and then record it, and a method for controlling the communication speed thereof. .

0002

2. Description of the Related Art A device of this type is equipped with a memory having a capacity capable of storing at least one page of image information, temporarily stores received image information in this image information memory, and receives one page of image information. When finished, recording will start, and during this recording,
CCITT. receives the next page while sequentially releasing the storage area of recorded image information. There are image communication devices that comply with the T30 recommendation. Such image communication devices usually use high-speed printers such as thermal printers or laser beam printers as image recording means, and when continuously receiving multiple pages of image information, they can basically receive all the images at the same communication speed. Receive pages.

Recently, some low-speed printers such as thermal type inkjet printers, which are capable of recording on plain paper and are easy to maintain, have been employed in this type of image communication apparatus.

0004

[Problem to be Solved by the Invention] However, if you use such a low-speed printer and try to record the received image by performing reduction processing to record it on cut paper, when multiple pages are continuously received, Image information memory overflow could occur. This is because the recording speed cannot catch up with the receiving speed if pages with a large amount of information continue.

The easiest way to avoid such inconveniences is to set the communication speed to be low in advance so that sufficient free memory capacity can be secured in the image information memory. However, on the receiving side, the amount of information on each page cannot be known until the end of reception, and the amount of information per page fluctuates considerably.
The communication speed has to be set assuming the worst case where similar pages are consecutive, and as a result, the communication speed has to be set much lower than the device's original capacity, leading to an increase in communication costs. It is uneconomical.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to avoid overflow of image information memory without unduly sacrificing communication speed even when a low-speed image recording means is used. The purpose of the present invention is to provide a communication speed control method and an image communication device that can perform communication speed control.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention has a configuration in which the communication speed is adaptively controlled depending on the free memory capacity of the image information memory each time one page of image information is received. More specifically,
The free memory capacity of the picture information memory at the time when one page of picture information has been received is detected, the communication speed for receiving the next page is determined based on this free memory capacity, and the next page is set according to the result of this decision. This system is configured to control the communication speed for receiving page image information.

[0008]

[Operation] With the above-described configuration, the present invention receives a next page at high speed if there is sufficient free space in the image information memory when a certain page is received, and reduces the receiving speed of the next page when there is insufficient free space. By lowering the speed, it is possible to prevent overflow of image information memory without unduly sacrificing communication speed, even when using an image recording means with a slow recording speed and recording received image information on cut paper after reduction processing, etc. can.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a facsimile machine according to an embodiment of the present invention. 101 is an NCU (network control circuit) that interfaces with line L, 1
02 is a modem (modulator/demodulator) that modulates and demodulates the image signal, 10
3 is R that detects the RTC signal among the received data.
TC detection unit 104 is a communication control unit that controls communication while controlling these NCU 101, modem 102, and RTC detection unit 103; 105 is at least one
An image information memory capable of storing image information (encoded data) for pages, 106 a memory management unit that manages information storage in the image information memory 105, 107 an error check and decoder of received image information, and transmitted image information. CO that performs encoding
DEC (code decoder), 108 is CODEC107
109 is a thermal inkjet that uses cut paper as recording paper. A low-speed printer such as a printer 110 is a reduction unit 108 and a printer 1.
This is a recording control unit that controls 09. 111
The communication control section 104, the image memory 105, the memory management section 106, the CODEC 107, and the recording control section 110
This is the system control unit that controls the

As will be described later, the system control section 111 sets the communication speed according to the free memory capacity of the image information memory 105, and the communication control section 104 performs necessary communication speed control according to the setting result. It will be done. Furthermore, the free memory capacity is calculated by the memory management unit 106.

The operation of the facsimile machine configured as described above will be explained, focusing on the case where a plurality of pages are successively received. In the following explanation, FIGS. 2 to 6 will be referred to. FIG. 2 is a flow diagram mainly for explaining the identification function in communication, FIG. 3 is a flow diagram for explaining the procedure after receiving image information, and FIG. 5 is a flowchart for explaining the communication speed setting operation, FIG. 5 is a flowchart for explaining the communication speed conversion operation, and FIG. 6 shows the relationship between the free memory capacity of the image information memory and the communication speed setting. It is a schematic diagram. Also,
The facsimile machine of this embodiment is CCITT. It complies with the T30 recommendation, and the signal names in the explanation are in accordance with the same recommendation.

[0012] When a call is received from the other party through the exchange, the line is connected, and a CNG signal is detected, the communication control unit 104 sends a CED signal from the modem 102 via the NCU 101 . The communication control unit 104 then repeats the operation of sending out the DIS signal and waiting for a response signal from the partner device, up to a certain T1 time limit (S201, S
202, S203).

[0013] If the communication control unit 104 detects a response signal from the partner device within time T1 and determines that the response signal is not a DTC signal but a DCS signal (S207,
S208), then the modem 102 is trained (S209). A training signal is sent from the partner machine, followed by a TCF signal. Communication control unit 104
If the TCF signal can be received normally, modem 10
It is determined that the training in step 2 was carried out normally (S2
10), responds with a CFR signal (S212), stores the set communication speed in an internal memory (not shown), and notifies the system control unit 111 of the start of image information reception (S213), and controls image information reception. Transition to (
S214). The image information transmitted from the other party's device is demodulated by the modem 102, and the demodulated image information (encoded data) is stored in an empty area of the image information memory 105 under the control of the memory management section 106.

The communication control unit 104 checks the detection of an RTC signal by the RTC detection unit 103 while receiving this image information (S215), and if an RTC signal is detected, 1
The system control unit 111 instructs the end of receiving image information for a page.
and waits for reception of a control signal from the other party (S206).

In this way, the image information of the first page is stored in the image information memory 105, and the system control unit 111 notified of this causes the CODEC 107 to perform an error check on the first page in the image information memory 105. Then, based on the results, the quality of the image information on the first page is determined. When the error check of the CODEC 107 is confirmed to be normal, if the printer 109 is in a recordable state, the image information of the first page in the image information memory 105 is decoded by the CODEC 107, and the decoded image information is converted to the reduction unit 108. Printer 109 for reduction processing
Start the operation to be recorded. During this operation, the memory management unit 106 sequentially releases the recorded image information storage area of the image information memory 105 as a free area, so that the free area of the image information memory 105 increases as the image information recording progresses. go. The same goes for the received image information of the second and subsequent pages; an error check is performed immediately after the reception is completed, and if it is normal, the image information of the previous page is sequentially recorded as soon as the recording of the previous page image information is completed.

Now, when the communication control unit 104 receives a control signal from the other party's device after receiving one page of image information, it determines whether the control signal is a DTC signal or a DCS signal (S207, S208). Control signal is DT
If it is neither a C signal nor a DCS signal, the communication control unit 104
determines whether the control signal is an MPS signal, an EOM signal, or an EOP signal (S301, S
302, S303). If either the MPS signal or the EOM signal is received, the communication control unit 104 determines that there is a next page. Then, the system control unit 111
Check whether the received image information quality judgment result is good (S
401), if it is good, the system control unit 11
1 to set the communication speed and transfer control.

System control unit 111 that received this instruction
In step S403, the status of the printer 109 is checked (S403
), when the printer 109 is in a recordable state, that is, when the printer 109 is not in a recordable state due to a malfunction or out of paper, set the communication speed for receiving image information of the next page using the following procedure.

The memory management unit 106 stores the image information memory 10.
5 is calculated (S404). A comparison judgment is made between the calculated free memory capacity immediately after receiving the previous page and the judgment threshold X (see Fig. 6) for insufficient free memory (S
405). When the free memory capacity is less than the threshold X,
If the communication speed is high, there is a risk of overflowing the image information memory 105, so it is determined whether the current communication speed (stored in the internal memory of the communication control unit 104) is the minimum communication speed V0 on the sending side. (S406). If the communication speed is not the minimum communication speed V0, a request is made to the communication control device 104 to change the communication speed to the minimum communication speed V0 to prevent overflow, and control is passed (S407).
. However, if the minimum communication speed is V0, the communication control unit 10
4. Transfer control without requesting a change in communication speed.

When the free memory capacity of the image information memory 105 is larger than the threshold value X, a comparison judgment is made between the free memory capacity and the free memory sufficiency judgment threshold value Y (see FIG. 6).
408). When the free memory capacity is smaller than the threshold value Y, control is passed to the communication control unit 104 without requesting a change in communication speed. When the free memory capacity is equal to or greater than the threshold value Y, high-speed communication is possible, so if the communication speed is the minimum communication speed V0 (S409, YES), a request is made to the communication control unit 104 to change to the maximum communication speed VT. and transfers control (S410
). On the other hand, if the current communication speed is not the minimum communication speed V0, control is passed to the communication control unit 104 without requesting a change in communication speed.

In this manner, the system control unit 111 sets the communication speed for receiving the next page. In the communication control unit 104, if there is no request to change the communication speed, the MC
The F signal is returned to the partner machine (S412). However, if modem training is required (S411, YES)
, responds with an RTP signal (S413). And E.O.
If the M signal has not yet been received (S414, NO), the process returns to step S201, and if the EOM signal has been received (S414, YES), the process returns to step S20.
Return to step 6 starting with step 6.

On the other hand, if a change in communication speed is requested, the communication control section 104 moves to the following procedure in order to convert the communication speed at the time of receiving the next page to the requested communication speed. First, an RTP signal is returned to the partner device (S415). If the EOM signal is not received (S416, NO)
It immediately waits for command reception from the other party's machine (S504).
), on the other hand, after receiving the EOM signal, it repeats sending the DIS signal and waiting for a response within a certain T1 time (S501, S502, S503).

[0022] Upon receiving the DCS signal from the other party (S5
05, YES), modem training (S5
08). If this is done normally (S509, YES)
), if there is a communication speed conversion request, that is, if the conversion to the requested communication speed is not completed (S511, YES),
Furthermore, it is determined whether the training speed is faster than the requested communication speed (S515), and if it is faster, F
Responds with a TT signal (S517), and step S504
Go back to the steps above and perform modem training again.

[0023] If the training speed is less than or equal to the requested communication speed (S515, NO), it responds with a CFR signal (S516), stores the current communication speed in the internal memory, and resets the speed conversion request (S51).
8). Then, it starts receiving the image information of the next page and monitors the detection of the RTC signal (S513, S51
4). When the RTC signal is detected, the system control unit 111 is notified that the reception of one page has been completed, and step S206
Return to the steps from. The system control unit 111 performs the same control as for the first page.

[0024] In step S509, training fails (
If the determination is NO, the FTT signal is returned (S51
0) Repeat the procedure from step S504, and if it is determined that there is no request (NO) in step S511, C
It responds with the FR signal and starts receiving image information (S512
, S513). Furthermore, if it is determined that the control signal received in step S505 is other than a DCN signal, or if there is no response from the other party even after T1 time has passed in the loop of steps S501, S502, and S503, a DCN is sent. and disconnect the line (S506, S5
07).

Up to this point, the explanation has been made assuming that the printer 109 is in a recordable state, but if the printer 109 is in a recordable state (S403
, NO), the system control unit 111 sets the current communication speed to that speed if it is other than the minimum communication speed V0, regardless of the size of the free memory capacity, and sets it to the maximum communication speed VT if the current communication speed is the minimum communication speed (S409, S410). In this case, unless the unrecordable state of the printer 109 is temporary, it is not possible to prevent the image information memory 105 from overflowing, so no control is intentionally performed to lower the communication speed.

[0026] If a timeout occurs in step S203, a DCN signal is returned and the line is disconnected (S2
04, S205). If it is determined in step S207 that the control signal is a DTC signal, the process moves to a transmission procedure. If it is determined in step S210 that training has failed, an FTT signal is sent (S211) and the process waits for command reception. If the process advances to step S303, it is not a serial communication, so if it is determined that an EOP signal is not being received, the line is immediately disconnected (S304), and in the case of an EOP signal, if the quality of the received image information is good ( S30
5, YES), MCF if training is not required
It responds with a signal (S308), and if necessary, it responds with an RTP signal (S307), and if the received image information is defective, it responds with an RTN signal (S309), and then it disconnects the line using a DCN signal from the transmitting side. Disconnect and end communication. If the image information quality is poor in step S401, the communication control unit 104 responds with an RTN signal (S402),
Next, the process proceeds to step S201 or S206 depending on whether the EOM signal has been received or not.

The functions of the system control unit 111 and the communication control unit 104 described above are based on the RO in which the program is stored.
M, a microprocessor that executes this program, a RAM as a work area, a program control system consisting of an external interface circuit, etc., or a dedicated hardware circuit. Regardless of which form is adopted, it will be easy for those skilled in the art to implement it based on the explanations so far, so presentation of each specific circuit configuration will be omitted.

[0028]

As is clear from the above description, the present invention performs control to increase the communication speed each time one page of image information is received, and when there is sufficient free space in the image information memory, to display the next page. When using an image recording means with a slow recording speed such as a thermal type inkjet printer, data is received at high speed, and when there is insufficient free space, the communication speed is controlled to reduce the reception speed of the next page. However, it has the effect of allowing recording to follow reception and preventing overflow of the image information memory without unduly sacrificing communication speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a facsimile device according to an embodiment of the present invention.

[Figure 2] Flow diagram mainly showing the identification function in communication

[Figure 3] Flow diagram for explaining the procedure after receiving image information

[Figure 4] Flow diagram for explaining communication speed setting operation

[Figure 5
]Flow diagram to explain communication speed conversion operation

[Figure 6]
Schematic diagram showing the relationship between the free memory capacity of the image information memory and the communication speed setting

[Explanation of symbols]

101 NCU 102 Modem 103 RTC detection section 104 Communication control unit 105 Image information memory 106 Memory management section 107 CODEC 108 Reduced section 109 Printer 110 Recording control section 111 System control section

Claims (2)

[Claims] Claim 1: In an image communication device that temporarily stores and then records image information received via a line in a memory capable of storing at least one page of image information, each time one page of image information is received, A communication speed control method comprising: controlling a communication speed for receiving the next page of image information according to the free memory capacity of the memory at that time. 2. A communication means for communicating with a partner device via a line, a storage means for storing image information received by the communication means, and a decoding means for decoding the image information stored in the storage means. , an image recording means for recording the image information decoded by the decoding means, and an empty memory capacity detecting means for detecting the empty memory capacity of the storage means at the time when one page of image information is received by the communication means. A speed determining means for determining a communication speed for receiving image information of the next page based on the free memory capacity detected by the free memory capacity detecting means; An image communication device comprising: speed control means for controlling a communication speed for receiving information in conjunction with the communication means.