JP2547753B2 - Communication control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a communication control device.

[Prior art]

Conventionally, there is a method of communicating data from a personal host such as a personal computer or a word processor using a telephone line. In this case, when the other party is facsimile, transmission delay may occur.

〔Purpose〕

The present invention eliminates the above inconvenience, and when the data received from the first terminal is stored in the storage means and the stored received data is transmitted to the second terminal according to the facsimile communication procedure, the storage means is used. When a predetermined amount of data is stored in the second terminal, a communication procedure signal is transmitted to the second terminal and a facsimile communication procedure is executed to prevent a communication error due to underrun of data in the storage means. .

〔Example〕

FIG. 1 is a conceptual diagram of this system. Reference numeral 1 is a host unit, which is connected to a communication function unit 3 by a cable 2.
The host transfers the control command and the image data to the communication function unit 3 and transmits the image to the partner FAX via the public telephone line 4 of FIG. The image data from the host uses MH compressed image data. The communication function unit of No. 3 consists of a protocol and modem to support the T.30 procedure, and has a function of G3 facsimile transmission, which is composed of an NCU unit. Further, the communication function unit 3 is provided with a call unit (not shown). When the handset 6 is connected to the communication function unit 3 and the host is not connected to the communication function unit 3, the CPU of the communication function unit 3 detects that the host is not connected. Switch the NCU relay to the call side to operate as a telephone.

Also, the CPU of the communication function unit 3 switches the relay of the NCU unit to the communication unit side based on the switching instruction from the changeover switch (not shown), and enables the communication by the handset 6. That is, the communication function unit 3 operates as a telephone in the same manner as when the host is not connected.

The normal sequence of an automatic incoming / outgoing call by the G3 facsimile binary procedure will be described with reference to FIG. The left side is the calling side and the right side is the called side. The calling side sends a CNG (calling tone) when the other party is connected after calling the other party by a dial signal. When the called party responds, it sends a CED (Called Station Identification) Tonal signal.

Then, the called side sends a binary signal of DIS (digital identification signal) to present the communication conditions. It is stipulated that the called side continues to send again for 30 to 40 seconds after 3 seconds until the calling side sends DCS (digital command signal) for the DIS signal.

The calling side sends a DCS signal according to the contents of DIS, sets the communication speed and specifications, sends training and data, and checks whether the called side can receive correctly.

The called side returns a CFR (reception preparation confirmation) binary signal if it can receive correctly. If it cannot be received, it returns an FTT (training failure) binary signal, starts from DCS again, and lowers the transmission rate if necessary. If the calling side does not transmit the image signal within 6 seconds after receiving the CFR, the line is disconnected as an error, so the communication function must receive the image data from the host at this point. CCITT
According to T.4, the G3 fax uses a compression method called MH or MR for the image signal. Normally, MH compression is performed and EOL (line end code) is added to each line. See image 1
The minimum transmission time of the line is defined by DIS, DCS, 0,5,1
The value of 0,20,40, mesc is set. Similarly, since the maximum transmission time for one line is specified as 5 seconds, if the data transfer rate from the host is slow, a file (continuous 0) is put between the data and EOL and waits. However, in the past, data is not often delayed, so even if the product is commercialized, inserting a long file will cause an error and insert the previous data due to a line error, or the drive of the paper feed motor will be stopped and the image will not be displayed properly. It is often continuous. Therefore, it is not possible to slow down the transmission speed by inserting a file.

After the image data is completed, Q in the figure is a binary signal of EOM (end of message) MPS (multipage signal) and EOP (end of procedure). In case of EOP, the called party is MCF
(Message confirmation) is sent and the calling side sends a DCN (disconnect command) to disconnect the line.

If you want to send more images under the same conditions, send MPS and MCF.
The next page data will be sent within 6 seconds after receiving the message. EOM is another condition, and if you want to send more images, you will return to the procedure from the first DIS.

FIG. 3 is an example of the sequence of the system of the present invention.
The personal computer and the communication function section are RS232C interfaces, and asynchronous serial signals are used. The commands and transmission control conform to the recommended communication method for personal computer communication devices (hereinafter referred to as JUST-PC procedure) announced by the Japan Post 1984. Except for commands that start with L (except LRS), they are exactly the same. Initially, the communication function block is initialized by the LMD command containing the local telephone number and user ID, and the communication function block responds with an LRS. Next, use the CNR command to enter the telephone number in the parameter section and make a call.

When the partner FAX is connected, the communication function unit sends an RNC confirmation signal to the host side and simultaneously sends CNG to the partner FAX. Opponent FA
When DIS is received next to CED from X, the communication function unit sends D to the host.
Receive the contents of IS by the communication signal of LRA. The host uses the LPT command, which includes the encoding method, recording width, recording length, maximum transmission rate, resolution, and page resend ability, for DCS information in accordance with DIS (where the transmission speed can be arbitrarily selected according to its own modem performance). However, an image error or underrun will occur unless the speed is lower than the data transmission speed between the hosts.
Read the speed specification information between the communication functions and set the value less than that to DIS
Must be the contents of. In a system that cannot be read as information, the transmission rate of the LRS response to the LMD may be measured. ) Send to the communication function section. LPT also invites confirmation of the previously sent page. For the first LPT, the LRS response is returned without parameters. After this, the host sends image data to the parameter section one after another with a CDT (data transmission command) command. The communication function block inserts a file due to lack of data from the host when the internal buffer stores more than a predetermined amount of data, or after checking the LPT command reception for sending the next page and then proceeding with the sequence below DCS. And prevents underrun. When the host finishes sending the image data, it will send the data one after another after the LPT command. After transmitting the image signal, the communication function unit checks the next page data amount in the internal buffer as described above, and if the amount is equal to or less than a predetermined value, EOM is output, and if sufficiently stored, the image signal is continuously transmitted by MPS.
The host notifies the communication function of the final pace with an LDE (data end command) signal following the image data. In the LRS parameters for the second and subsequent LPT commands, PIC = 0 means MCF and PIC = 1 means RTN (reception failure notification). When PIC = 1, if there is a retransmission capability declaration in the LPT, it is possible to interrupt the image data transmission (CDT) again after the LPT even while sending the next page. In the case of RTN, it is specified to start from DIS, so the data delay of the host will be saved as well. Approximately 2K bytes is desirable as a buffer.

As described above, according to the present invention, when the data received from the first terminal is stored in the storage means and the stored received data is transmitted to the second terminal according to the facsimile communication procedure, When a predetermined amount of data is stored in the storage means, the communication procedure signal is transmitted to the second terminal to execute the facsimile communication procedure, so that the communication error due to the underrun of the data in the storage means can be prevented.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the entire system, FIG. 2 is a sequence diagram after connection of the G3 facsimile system to the telephone network, FIG. 3 is a sequence diagram of the procedure of the present invention, and FIG. 4 is a sequence flow focusing on communication functions. It is a chart.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Takushi Nakatsuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-62-150963 (JP, A) JP-A-SHO 62-168457 (JP, A) JP 61-62274 (JP, A) JP 63-166341 (JP, A) JP-B-8-22011 (JP, B2)

Claims (1)

(57) [Claims] 1. A communication control device for receiving data from a first terminal and transmitting the received data to a second terminal according to a facsimile communication procedure, comprising: receiving means for receiving the data from the first terminal; Storage means for temporarily storing the data received by the receiving means, and the facsimile communication procedure is executed according to the amount of data in the storage means, and the data in the storage means is stored according to the execution of the facsimile communication procedure. A transmitting means for transmitting to the second terminal, wherein the transmitting means transmits the second communication procedure signal to the second terminal in response to the first communication procedure signal from the second terminal. In this case, the communication control device transmits the second communication procedure signal when a predetermined amount of data is stored in the storage means.