JPH0422389B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a facsimile communication system, and in particular,
This paper relates to a facsimile communication method for switching modes between continuously sent documents in a Group 3 facsimile device that complies with CCITT Recommendation T30.

[Conventional technology]

In the conventional facsimile communication method for Group 3 facsimile devices that perform mutual communication using standard communication mode and non-standard communication mode in accordance with CCITT recommendation T30, for example, document information is transmitted between continuously sent documents. It performs mode conversion such as switching the scanning line density depending on the density of the image.

As shown in FIG. 2, the mode conversion control sequence involves exchanging control signals between the transmitter and the receiver.

If you are currently feeding an original in normal mode (scanning line density of 3.85 lines per 1 mm), and you want to feed the subsequent original in fine mode (scanning line density of 7.7 lines per 1 mm), the previous original should be Fine mode settings are made on the transmitter side during image transmission.

When the sending of the previous original is finished, the transmitter sends a message end signal EOM to notify the receiver that mode conversion is to be performed.

After detecting the message end signal EOM, the receiver sends a message confirmation signal MCF that notifies the transmitter that it has recognized the message end signal EOM.

After sending the message confirmation signal MCF, after a waiting time of approximately 6 seconds has elapsed, the receiver sends a non-standard equipment signal NSF indicating non-standard capability to the transmitter, and a receiving station identification signal CSI for confirming the identity of the called subscriber. Shifts to the phase B control signal procedure for sending an initial identification signal consisting of a standard CIS.

However, the above-mentioned waiting time of approximately 6 seconds is intended to prevent failures by repeatedly performing transmission when the transmitter cannot recognize the message confirmation signal MCF due to noise or the like.

[Problem that the invention seeks to solve]

In such a control case, it is necessary to set a long waiting time from sending the message confirmation signal MCF to moving to the next control signal procedure.
Therefore, there is a drawback that it takes a long time to send one document electronically.

[Means for Solving the Problems] An object of the present invention is to solve the above-mentioned drawbacks by transmitting a calling station identification signal after the transmitter detects the message confirmation signal MCF, and transmitting the message confirmation signal.
To provide a facsimile communication system that does not require waiting time settings by notifying the receiver that it has recognized an MCF so that the receiver can immediately proceed to the next control signal procedure.

The facsimile communication system of the present invention is a Group 3 facsimile device that performs mutual communication in standard and non-standard communication modes in accordance with CCITT Recommendation T ₃₀ , and is a facsimile communication system that performs mode conversion between continuously sent documents. In this method, after detecting a message confirmation signal from the receiving side, the transmitting side transmits a calling station identification signal corresponding to a predetermined communication mode, and the receiving side follows a predetermined control signal procedure to detect the calling station identification signal. configured to migrate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a control sequence diagram showing one embodiment of the present invention.

In FIG. 1, it is assumed that the mode of the transmitter is switched to the fine mode while the original is being sent in the normal mode as described above. When image sending in the normal mode is finished, the transmitter sends a message end signal EOM to notify the receiver that the communication mode will be changed from the next original.

After the receiver detects the message end signal EOM,
It sends a message confirmation signal MCF to notify the transmitter that it has recognized the message end signal EOM and that it is ready to receive the next image transmission.

When the transmitter detects the message confirmation signal MCF, it sends a calling station identification signal CNG in the standard communication mode or a calling station identification signal NCNG in the non-standard communication mode to the receiver to notify that the signal has been recognized.

The calling station identification signal CNG or NCNG is a signal that is repeatedly transmitted at a specific frequency (NCG is 1100 Hz) for 0.5 seconds and then interrupted for 3 seconds, and the receiver can normally detect the signal 0.5 seconds after the beginning.

When the receiver detects the calling station identification signal CNG or NCNG, it enters the phase B control procedure during the subsequent signal interruption period. That is, it sends to the transmitter an initial identification signal consisting of a digital identification signal DIS characterizing standard CCITT capabilities, a non-standard equipment signal NSF indicating non-standard capabilities, and a receiving station identification signal CSI for identifying the called subscriber. and communicate their abilities.

After the transmitter detects the initial identification signal from the receiver,
In the standard communication mode, the reception command signal consists of the transmitting station identification signal TSI and digital command signal DCS, which are displayed for identifying the transmitting station, and in the non-standard communication mode, the transmitting station identification signal TSI and the non-standard equipment signal. After sending a reception command signal consisting of the non-standard equipment setting signal NSS in response to the NSF to the receiver, the process moves to the next step.

Here, a code indicating that the scanning line density set while the previous original was being sent is in fine mode is included in the above-mentioned digital command signal DCS and non-standard equipment setting signal NSS and transmitted to the receiver. . The receiver detects these signals and sets the scan line density to fine mode.

Next, the transmitter sends a training check signal.
Send the TCF to the receiver through the modem, check the training, check whether the transmission speed is compatible with the transmission path, and set the modem speed.

After setting the transmission speed, the receiver sends a reception readiness confirmation signal.
Sends a CFR to the transmitter to notify it that all reception preparations are complete.

This completes the control procedure before image feeding, and image feeding in fine mode is performed. The same applies to the case of converting from fine mode to normal mode.

In addition to switching the scanning line density, the mode conversion is
It is also possible to change the image size, artificially change the transmission speed, etc.

The above-described changes in the control procedure can be easily achieved without adding any hardware by modifying the program of the communication control _{microprocessor} in the facsimile device, and can be easily achieved without adding any hardware. Implementation is possible for Group 3 facsimile machines.

〔Effect of the invention〕

As described above, in the facsimile communication system of the present invention, instead of the receiver transmitting the message confirmation signal and then waiting a predetermined time before proceeding to the subsequent control signal procedure, the transmitter detects the message confirmation signal. By notifying the receiver of this, the receiver can immediately proceed to the subsequent control signal procedure, so there is no need to set a waiting time to prevent malfunctions, and the required transmission time for one communication is reduced. This has the effect of shortening the time.

[Brief explanation of drawings]

FIG. 1 is a control sequence diagram showing an embodiment of the present invention, and FIG. 2 is a control sequence diagram showing a conventional example.

Claims (1)

[Claims] 1 Group 3 facsimile devices that communicate with each other in standard and non-standard communication modes in accordance with CCITT Recommendation T30, in a facsimile communication method that converts modes between consecutively sent documents,
After detecting a message confirmation signal from the receiving side, the transmitting side sends out a calling station identification signal corresponding to a predetermined communication mode, and after detecting the calling station identification signal, the receiving side shifts to a predetermined control signal procedure. A facsimile communication method characterized by: