JP2000307841A - Facsimile equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce load on CPU by setting an access interval to a modem in accordance with line speed information of communication. SOLUTION: A CPU control circuit 2 receives image transmission or reception start instruction. When it is for transmission start, the circuit 2 sets various kinds of parameters for converting a mode into the image transmission mode concerning the modem inside a communication control part 5. Then the circuit 2 obtains modem line speed information for executing transmission/reception from the modem inside the control part 5. Modem access interval information with respect to the line speed is obtained from modem line speed information and a model access interval deciding table. Then the circuit 2 sets the access interval during image transmission/reception with respect to the modem in the part 5 and starts the transmission/reception of image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to access timing to a modem chip in a facsimile machine.

[0002]

2. Description of the Related Art A conventional modem transmits one line to a line during a transmitting operation.
When sending or receiving bytes of data,
Each time 1-byte data is received from the line, an interrupt is generated for the facsimile machine. When an interrupt is generated from the modem on the facsimile machine side, 1-byte image data for transmission is transferred to the modem at the time of transmission operation. At the time of receiving operation, facsimile image data is transmitted and received by acquiring and saving received data from the modem.

In recent years, Rockwell's modem R2
88f, the modem has a communication image data buffer of more than 10 bytes in the modem, and the facsimile device accesses the communication image data buffer at regular intervals. If there is free space, the image data for transmission corresponding to the free buffer is transferred to the image buffer for communication, and the modem transmits the data in the image buffer for communication to the line. At the time of receiving operation, the facsimile apparatus acquires and saves all data of up to tens of bytes transmitted from the line and stored in the communication image buffer at the time of modem access. With the above-described image data transfer method, data of more than ten bytes is processed by one access to the modem.

[0004]

However, in the above-mentioned conventional facsimile apparatus, the access interval to the modem is constant. Usually, the access interval is set based on the maximum line speed of 33600 bps of the facsimile communication. ing. For this reason, at a line speed of 33600 bps,
Even at an ideal access interval, when the line speed is 16800 bps, which is half of the above speed, at the time of transmission, writing with the data still half remaining in the communication image buffer, or at the time of reception, the communication image buffer Means that data is read in a state where only half of the data is contained in the data.

Further, when the line speed is 2400 bps, there is no change in the data in the communication image buffer in one access, and only one byte of data is written to the communication image buffer by several accesses. Or, the lower the line speed, the more unnecessary modem access is made.

SUMMARY OF THE INVENTION An object of the present invention is to provide a facsimile apparatus which reduces unnecessary access to a modem and consequently reduces a load on a CPU.

[0007]

According to the present invention, the access interval to the modem is changed according to the line speed during facsimile communication.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing a facsimile apparatus according to one embodiment of the present invention.

[0009] Character generator (CG) circuit 1
Is a circuit for generating characters to be printed on a report or the like. The CPU control circuit 2 has a ROM section and a RAM section and controls the entire system. The direct memory access (DMA) circuit 3 transfers image data between memories via the image bus 14 without passing through the CPU control circuit 2. The page memory 4 is a memory that expands image data for each page, and the communication control unit 5 manages outgoing / incoming calls with the destination terminal and control of transmission / reception of image data according to a predetermined communication protocol.

[0010] The key input device 7 receives an instruction by a key input from an operator. The display device 8 displays a message on a liquid crystal display (LCD),
Various information such as out of paper, out of ink, and communication status is notified. The scanner device 9 reads a document in a designated mode such as size and density, and the printer device 10 outputs image data and character data to paper.

The I / O control unit 6 includes a system bus 15, a key input device 7, a display device 8, a scanner device 9,
The input / output devices 7 are interposed between the printer devices 10.
Controls the control of. An image encoding / decoding circuit 11 compresses and expands image data, and a small computer system interface (SCSI) 12 controls an interface operation of a hard disk 13 composed of a nonvolatile memory.

Then, the CG circuit 1, the DMA control circuit 3,
The page memory 4, the communication control unit 5, the scanner device 9, the printer device 10, and the SCSI interface 12 are connected to each other via an image bus 14, and the CG circuit 1, the CPU
Control circuit 2, DMA control circuit 3, page memory 4, communication control unit 5, I / O control unit 6, image encoding / decoding circuit 1
1. SCSI interface 12 is connected to system bus 15
Are connected to each other.

FIG. 2 is a diagram showing a modem access interval determination table set by the modem access interval setting means in the above embodiment.

The line speed 20 is a transmission speed when transmitting and receiving image data. The modem access interval 21 is a periodic interval time for causing an interrupt periodically and accessing the modem chip.

Next, the operation of the above embodiment will be described.

FIG. 3 is a flowchart showing an image transmission / reception setting operation in the above embodiment in which the modem access interval is made variable and image data transmission / reception is started.

In step S30, the CPU control circuit 2 receives an instruction to start image transmission or reception.
The U control circuit 2 controls the modem inside the communication control unit 5
Various parameter settings for setting the image transmission mode are performed.

If the instruction is a reception start instruction, in step S32, the CPU control circuit 2
Various parameters for setting the image receiving mode are set for the internal modem.

Next, in step S33, the CPU control circuit 2 acquires, from the modem in the communication control unit 5, information on the modem line speed for transmission and reception.

Next, in step S34, modem access interval information for the line speed is obtained from the modem line speed information and the modem access interval determination table of FIG. The modem access interval 21 is such that the conventional modem has a 16-byte FIFO (communication image data buffer inside the modem), so that one access to the modem stores about 7 to 10 bytes of data (at the time of transmission). Alternatively, it is a value calculated based on data acquisition (at the time of reception). For example, in the case of 33600 bps, the time required for sending and receiving 1-byte data is 1 * 1000/3360
Since 0 is 0.24 ms, the data transmission / reception time of about 8 bytes is obtained in 2 ms.

Then, in step S35, the CPU
The control circuit 2 sets an access interval during image transmission / reception with respect to the modem inside the communication control unit 5 and starts transmission / reception of image data.

[0022]

According to the present invention, when the image transmission speed is low (2400 bps), the access interval to the modem is extended, and the image transmission speed is high (33600 bps).
In such a case, by making the access timing to the modem variable, for example, by narrowing the access interval to the modem, it is possible to reduce the load on the CPU.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a configuration of a facsimile apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing a table for determining a modem access interval set by the modem access interval setting means.

FIG. 3 is an image transmission / reception setting flowchart for starting transmission / reception of image data by changing a modem access interval in the embodiment.

[Explanation of symbols]

 1 CG circuit, 2 CPU control circuit, 3 DMA, 4 page memory, 5 communication control unit, 7 key input device, 8 display device, 9 scanner device, 10 printer device.

Claims (1)

[Claims] 1. A modem having a communication data buffer of several bytes inside a modem, wherein a facsimile apparatus accesses the communication data buffer at regular intervals and reads out the data in the communication data buffer, or reads out the data in the communication data buffer. In a facsimile apparatus capable of transmitting and receiving data to and from a modem by writing data in a data buffer, line speed information obtaining means for obtaining communication line speed information; speed information obtained by said line speed information obtaining means A modem access interval setting means for setting an access interval to the modem in accordance with the following.