JP3034349B2 - Facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus having an ECM function.

[0002]

2. Description of the Related Art In a conventional facsimile apparatus having an ECM function, a PPR signal does not include an element directly indicating that a retraining error has occurred in a receiver.
For this reason, when the PPR signal is received, the unreceivable frame indicated by the PPR signal is transmitted regardless of the content of the PPR signal except when the PPR signal is received a predetermined number of times repeatedly. Had been resent.

[0003]

However, in a high-speed signal using short-circuit training, 1
It cannot be recovered if a retraining error occurs. Therefore, in this case, a predetermined number of PPs
When the R signal was received, the meaningless retransmission process was repeated until the CTC signal was transmitted and the formal backing was performed.

FIG. 4 shows an example of a retransmission processing protocol based on such general short training. In FIG. 4, even when a retraining error occurs, the transmitter does not perform a test such as that the receiver has caused a retraining error. become. However, as described above, the training error cannot be eliminated due to the short training, and a training error occurs every time retransmission is performed.

The CTC signal is transmitted only when the training error has not been resolved even after repeating the predetermined number of times, and as a result, the next retransmission procedure is performed from the long training. Therefore, at this point, the training error is eliminated for the first time, and a long communication time is required.

[0006]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, in a facsimile apparatus having an ECM mode communication function that uses short training for high-speed signals, receiving means for receiving a PPR signal from the image signal transmission destination during transmission of an image signal following short training, When the means receives the PPR signal including the image signal retransmission request, it regards the image signal transmission destination as a retransmission request due to the occurrence of a retraining error, and transmits a CTC signal indicating the same speed as that of the image signal being transmitted. A retransmission means for performing a retransmission procedure and performing a retransmission procedure based on a short training procedure a predetermined number of times when the receiving means receives a PPR signal that does not include a retransmission request for the first frame.

[0007]

With the above arrangement, the communication time can be shortened without repeating retransmission in useless short training repeatedly.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a facsimile apparatus according to an embodiment of the present invention.
Reference numeral 1 denotes a CPU that controls the entire apparatus of this embodiment including a communication control procedure control in accordance with a communication control procedure described later, for example, according to a program stored in a ROM 2; This is a reading device for reading a transmission document image. 4 is a modem for transmitting and receiving data using an analog line, 5 is a network control circuit (NCU) for interfacing with the communication network 10,
Reference numeral 6 denotes a communication parameter RAM for storing the communication control procedure of this embodiment, parameters for executing the procedure, and the like.

Reference numeral 10 denotes a communication network to which the facsimile apparatus of this embodiment is connected, and reference numeral 20 denotes another communication apparatus to which the communication network 10 is connected. The communication parameter RA described above
FIG. 2 shows an example of the protocol parameter frame of this embodiment stored in M6. In FIG. 2, 21 is a high-speed signal head frame number, and 22 is a protocol parameter N.
It is. It is determined from the protocol parameter N whether the signal is a PPR signal including a retransmission request for an image signal or a PPR signal not including a retransmission request for a first frame.

The communication control procedure of the present embodiment having the above configuration will be described below with reference to the communication control procedures of FIGS. In the following description, a case will be described as an example where the apparatus of this embodiment transmits facsimile data to another apparatus 20 connected to the communication network 10. When a document to be transmitted to the reading device 3 is set and preparation for transmission is completed, the other device 20 is called. Then, a pre-procedure process as shown in FIG. 3 is performed to establish a communication path with the receiver (the other device 20). Then, following the reception of the "CFR" signal, the first image signal transmission processing (PIX, PPS EOP transmission processing) is performed. Then, the PPR signal from the partner device 20 is received via the NCU 5 and the modem 4. At this time, if a retraining error has occurred at the time point in FIG. 3, the PPR signal received at the previous time point indicates the error.

For this reason, the CPU 1 that recognizes that the PPR signal indicates an error can be assumed to have received the PPR signal due to the occurrence of the error at the time of FIG.
In this case, even if the image signal is transmitted in the short training procedure as shown in FIG. 4, a retraining error occurs again. For this reason, in the present embodiment, the CTC signal is transmitted as shown in FIG. 3 and the receiver 20 is instructed to retransmit the next image signal by long training.

In the retransmission control of the next image signal, since the CTC signal has been transmitted and received, the image signal is transmitted and received in long training according to the rules of CCITT as shown in FIG. As a result, the previous training error is resolved, and normal communication becomes possible. As a result, as compared with the conventional procedure as shown in FIG. 4, all the time required for the procedures shown in FIG.

Note that, in the ECM mode G3 transmission using short training for a high-speed signal according to the present embodiment, PP
If the first frame of the high-speed signal transmitted when the R signal is received is a PPR signal indicating that reception was not possible, a retraining error occurs in the procedure shown in FIG. 3 as described above. The long training is performed by transmitting a CTC signal indicating the same speed as the previously transmitted high-speed signal.

However, when a PPR signal that does not include a retransmission request for the first frame is received, the retransmission procedure based on the short training procedure is performed a predetermined number of times instead of performing the communication control procedure of FIG.
The present invention may be applied to a system including a plurality of devices or an apparatus including a single device.

It is needless to say that the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[0016]

As described above, according to the present invention, even when a retraining error occurs, the error can be recovered in a minimum time, and the communication time can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment according to the present invention.

FIG. 2 is a diagram illustrating contents of a communication parameter frame stored in a communication parameter RAM according to the present embodiment.

FIG. 3 is a diagram illustrating a communication control procedure when a retraining error occurs according to the embodiment;

FIG. 4 is a diagram showing a communication control procedure when a retraining error occurs in a conventional example.

[Explanation of symbols]

 1 CPU, 2 ROM, 3 reader, 4 modem, 5 NCU, 6 communication parameter RAM, 10 communication network, 20 other devices.

Claims (1)

(57) [Claims] 1. A facsimile apparatus having an ECM mode communication function using short training for a high-speed signal, receiving means for receiving a PPR signal from a destination of the image signal during transmission of an image signal following short training. When the receiving means receives a PPR signal including a request for retransmission of an image signal, the receiving means transmits a CTC signal indicating the same speed as that of the image signal being transmitted, assuming that the PPR signal is a retransmission request due to the occurrence of a retraining error at the image signal transmission destination. Retransmission means for performing a retransmission procedure from training, and performing a retransmission procedure based on a short training procedure a predetermined number of times when the receiving means receives a PPR signal that does not include a retransmission request for the first frame. Facsimile machine.