JPH03224356A - Picture data transmission system - Google Patents

Abstract

PURPOSE:To eliminate useless communication time by declaring in advance a receptible data capacity of a picture signal from a reception station to a transmission station as the capability of its own station. CONSTITUTION:A microprocessor 10 calculates a receptible capacity through the sum of a capacity obtained by an output enable capacity detection circuit 23 and a capacity of a nonuse area in a deputy reception buffer memory 22 and sends the information to a transmission station while being integrated into an NSF frame. Thus, a transmission station compares quantity of a picture data to be sent with the receptible capacity of a reception station and when the transmission station discriminates it that the picture data cannot be sent out, the communication is terminated without sending a picture data or the transmission mode is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image data transmission method that can be applied as a transmission protocol for facsimile machines and the like.

[Conventional technology]

Conventionally, as a protocol for transmitting images via telephone lines, for example, the GIII standard has been recommended by CCITT.
2O protocol is used. In this T2O,
The facsimile transmission procedure is divided into five phases as shown in FIG.

First, in phase A, a facsimile device is connected to a telephone line in response to a telephone call (call origination) or telephone call (incoming/receiving). In phase B, the functions of the receiving station are identified, the transmitting station issues a receive command to the receiving station, and the receiving station responds to the receiving command to the transmitting station. In phase C, image data is transmitted and received. In phase D,
Verification of the images transmitted in Phase C is performed. After Phase D, return to Phase B or C,
Either the next image transmission is continued, or the process proceeds to phase E and the line is disconnected.

[Problems to be Solved by the Invention] In the above-mentioned phase B, the information shown from the receiving station to the transmitting station includes information (1 bit) indicating whether or not the receiving station is equipped with the receiving function of the GrII standard. , the transmitting station uses this information to determine whether it is possible to transmit in GII mode. If the transmitting station determines that it has reception capability, it sends a reception request to the receiving station,
When the receiving station responds with a permission signal, the transmitting station proceeds to phase C, transmits an image signal, and reaches phase D.

However, once the image signal starts to be sent in phase C, it will be sent to the end, so if the receiving station runs out of paper during phase C, the transmitting station will not have a chance to know about the abnormality. The drawback was that communication time was wasted.

As a countermeasure to this problem, a method has been considered in which the receiving station is equipped with a large-capacity receive buffer memory, and when an abnormality occurs, the receive buffer receives data on behalf of the receiver, but even with this countermeasure, the receive buffer memory capacity is limited. Since the buffer is finite, there is a possibility that the buffer will run out someday and communication time will be wasted.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide an image data transmission system that eliminates wasted communication time by notifying a transmitting station in advance of the receivable capacity of a receiving station.

[Means for Solving the Problem] In the present invention, before transmitting image data, a receiving station declares its reception capability to a transmitting station, and the transmitting station executes a predetermined transmission procedure based on the information. In this transmission method, the receiving station detects the receivable capacity of its own station in advance and declares the detected capacity to the transmitting station, and the transmitting station determines the amount of image data to be transmitted and the receiving station's received capacity. If it is determined that the image data cannot be transmitted completely by comparing the available capacity, the communication is terminated without transmitting the image data, or the transmission mode is changed.

[Function] According to the present invention, wasted communication time can be eliminated by the receiving station declaring in advance to the transmitting station the data capacity of image signals that can be received as the capability of the own station.

[Example] In the GIII mode facsimile machine described in detail below, the transmitting station compares the amount of data sent by itself in phase C with the reception capacity disclosed by the receiving station in phase B, and Image transmission is terminated by estimating station overflow to prevent communication time from being wasted.

Alternatively, in Phase B, if the transmitting station can count or estimate the capacity of the image data to be transmitted, it can estimate the overflow of the receiving station by comparing it with the receiving capacity, and then enter Phase C and begin image transmission. Communication can be terminated without incident.

Furthermore, when the other station has transmission data, the transmission/reception mode can be switched and changed to the reception mode.

Here, the signal name that the receiving station can declare to the transmitting station in phase B is DIS (digital identification signal:
Dfgital Identificat fon SL
gnal) and NSF (non-standard equipment: Non-3t
Andard Facilities). This D
IS is used for the contents of the T-series recommendations in CCITT, and NSF can be used for other proprietary procedures. Therefore, a field expressing the receivable capacity can be provided in this NSF. Due to this,
It is also possible to communicate with existing Gm mode facsimile machines.

If the amount of information in the transmitted document is already known, the transmitting station will estimate the amount of information (otherwise, the amount of generated information will be estimated according to the specified transmission mode) and the information available for reception disclosed to the NSF. If it is determined that the data cannot be transmitted, a DCN (disconnect command: Disconnect) is sent to the receiving station as shown in Figure 1 (A).
Terminate communications. Alternatively, as shown in Figure 1 (B), NSS (non-standard function setting: Non-3tanda
rd Facilities 5et-upl includes information on insufficient reception capacity and transmits it to the receiving station to terminate the communication. Here, NSS is a control signal that can include information for a unique procedure, similar to NSF.

FIG. 3 is a configuration block diagram of an image transmission device (facsimile device) for implementing the present invention. Here, lO
is a microprocessor that controls the execution of procedures for connecting, disconnecting, and transmitting input and output lines for control information and image information. 12
is an image input device that reads an original or digitizes a video signal. 14 is an image output device such as a printer or a magnetic disk that prints or stores the received image data. 16 is a serial/parallel converter;
18 is a modem, and 20 is an NCU (network control unit).

Reference numeral 22 denotes a buffer memory for proxy reception that temporarily stores image data when the image output device cannot output due to paper shortage or the like. 23 is a circuit for detecting the output capacity of the image output device.

Image data from image input device 12 is sent by microprocessor 10 to S/P converter 16 where it is converted to serial data and sent to modem 18. Modem 18 modulates the serial data from S/P converter 16 or data from microprocessor 10, and the modulated signal is sent via NCU 20 to the telephone line.

Control signals such as DIS and NSF are transmitted and received within HDLC frames.

The microprocessor 10 connects the HDLC frame to the line.
When outputting data, a signal is output to the line via the S/P converter 16, modem 18, and NCU 20. G
III facsimile image data without HDLC framing is sent to the modem 18 and NCU 20.
Outputs a signal to the line via. The same applies when receiving signals from a line.

The microprocessor 10 includes an output capable capacity detection circuit 23
and the capacity obtained by the interception buffer memory 22
Add the capacity of the unused area to obtain the receivable capacity, N
It is included in an SF frame and transmitted to the transmitting station.

[Effects of the Invention] As explained above, according to the present invention, it is possible to grasp the receivable capacity of a receiving station before transmitting image data, so it is determined that the image data to be transmitted cannot be sent completely. In this case, communication can be terminated without starting image transmission, and unnecessary consumption of communication time can be avoided.

[Brief explanation of drawings]

Fig. 1 is a control procedure sequence diagram illustrating an embodiment of the present invention, Fig. 2 is a diagram illustrating a general facsimile communication procedure, and Fig. 3 is an image transmission device for implementing the present invention. It is a block diagram showing an example. 10...Microprocessor, 20...NCU. 22... Buffer memory for proxy reception, 23... Output available capacity detection circuit. Engineering drawing

Claims (1)

[Claims] 1) A transmission method in which a receiving station declares its reception capability to a transmitting station before transmitting image data, and the transmitting station executes a predetermined transmission procedure based on the information. Then, the receiving station detects its own receivable capacity in advance and declares the detected capacity to the transmitting station, and the transmitting station compares the amount of image data to be transmitted with the receiving station's receivable capacity. However, if it is determined that the image data cannot be completely transmitted, the image data transmission method is characterized in that the communication is terminated without transmitting the image data, or the transmission mode is changed.