JPS5877372A - Facsimile device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a facsimile machine, and in particular, when the processing capacity of a repeater on the receiving side is insufficient, coded data from an automatic repeat request unit (hereinafter referred to as ARQ) cannot be processed. For example, when the FIFO buffer of the decoder is about to overflow, data transfer from ARQ is prohibited and waits until data can be input to the FIFO buffer. If the encoded data of the frame correctly received from RQ cannot be output, send ACK.
This is a system in which the transmission of new encoded data from the transmitting side is made to wait until the data can be output again from ARQ as a NACK signal without outputting a signal. For example, as stated in Section 4.4 of CCITT Recommendation T, when the encoded data for each line is less than a predetermined time T, it is specified that a FILL bit is added to make it more than T. ing. This was determined by taking into consideration the processing time of the scanner, scanner, and plotter, and T is 2.5ms.
/line to 40 m s /line is common.

FIG. 1 is an electrical block diagram for explaining an example of a facsimile machine having an automatic repeat request device.
Reference numeral 10 indicates the transmitting side, and the adder indicates the receiver 1δ side.
[Hybrid transformer] 5, receiving side light consists of hybrid transformer 2], modem η, ARQ wing, decoder part,
The receiving side, which consists of a programmer 5, etc., checks the frame sent from the transmitting side 10 for errors, and in the case of an error, instructs the frame to be retransmitted. That is, the transmitting side IO encodes the image information read by the scanner 11 with the encoder 12, further frames it with the ARQ 13, modulates it with the modem 14, and outputs it to the line via the hybrid transformer 15. Further, the ARQ 13 receives the ACK signal via the hybrid transformer 15 and sends out the next frame, and when it does not receive the ACK signal, retransmits the frame in error. On the other hand, the receiving side is
The data output from the modem ρ is checked by ARQZ3, and if it is correct, only the encoded data is output to the decoder, and at the same time, an ACK signal is output to the line via the hybrid transformer 21, and the ARQ23 detects the error. If a frame is detected, the frame waits for the frame to be played back without outputting an ACK signal. However, in the above-mentioned facsimile machines, if the processing power of the plotter or decoder on the receiving side is insufficient for some reason, the data from ARQ cannot be accepted and an error may occur after the ARQ. .

Generally, the encoder 12 shown in FIG.
The decoder has a FIFO buffer 12b at the rear stage, and as shown in Figure 3, the decoder has a FIFO buffer 24a at the front stage and a line buffer 24b at the rear stage. Therefore, in FIG. 2, for example, increasing the number of line buffers 12a is equivalent to artificially speeding up the processing time of the scanner.
This means that the number of bits can be reduced. Also, FI
By increasing the size of the Fo buffer 12b, it is also possible to reduce FILL bits from the encoded data output from the encoder 12 to the FIFO buffer 12b. In addition, in FIG. 3, the size of the FIFo buffer 24a is increased or the size of the line buffer 24a is increased.
By increasing the number of b, it becomes possible to receive encoded data with fewer FILL pits.

However, in reality, unnecessarily increasing the size of the F and line buffers increases costs and is not practical, and the encoder on the transmitting side can grasp the capabilities of the decoder and plotter on the receiving side. Therefore, it is difficult to transmit encoded data using the receiving side's maximum reception capability.

The present invention was made in order to solve the above-mentioned drawbacks of the conventional technology. For example, when the decoder's FIFO buffer is about to overflow, it prohibits data transfer from ARQ, waits until data can be input to the FIFO buffer, and cannot output the encoded data of the correctly received frame. When the time is N, without outputting the ACK signal
The transmission of new encoded data from the transmitting side is waited until the ARQ data can be outputted again as an ACK signal, so that the encoder on the transmitting side can encode without being aware of the capabilities of the decoder on the receiving side. This allows encoded data to be transmitted at maximum capacity.

FIG. 4 is an electrical block diagram for explaining one embodiment of the present invention. In the figure, 10 indicates the transmitting side, and 10 indicates the receiving side. The transmitting side is the same as shown in FIG. 1. This is the same as the transmitting side 10, and the receiving side uses ARQ2 at the receiving side shown in FIG.
A READY signal is input between A R'Q 23 and the decoder 24 on the receiving side, and FIG.
The details of the interface section are shown below.

As shown in FIG. 5, the receiving 11111 F I FO buffer 24a has a FULL detector 24C,
When the IFO buffer 24a becomes FULL, the FULL
The READY signal from the detector 24c is set to 0'' (however, when the PIFO buffer is not FULL, it is set to 11''). On the other hand, the ARQ 23 puts the encoded data of the correctly received frame into the shift register 23a, and uses the shift clock (S, HIFT CLOCK) to
Transfer the encoded data to the decoder. However, at this time, if the READY signal from the decoder Jun is ), the AND gate circuit 23b is disabled and the shift register 23a is disabled.
data transfer is prohibited. Also, ARQ23 is RE
When the AD7 signal is 10'' and data transfer is not possible, a NACK signal is output without outputting an ACK signal.

As is clear from the above description, according to the present invention, AR
Highly efficient transmission of encoded data can be achieved simply by adding a READY signal between Q and the decoder.

[Brief explanation of the drawing]

FIG. 1 is an electrical block diagram for explaining an example of a conventional facsimile machine, FIG. 2 is a detailed diagram of the encoder 12 shown in FIG. 1, and FIG. 3 is a diagram similar to that shown in FIG. 4 is an electrical block diagram for explaining one embodiment of the present invention, and FIG. 5 is a detailed diagram of the decoder U section shown in FIG.
23 and a decoder 24; FIG. 10... Sending side, 11... Scanner, 12...
Encoder, 13... ARQ, 14... Modem, 15.
・Hybrid transformer, addition...receiving side, 21...
Hybrid transformer, n...modem, n...AR
Q, Z3a...Shift register, 23b...AND gate circuit, Jun...Decoder, 24a...FIFO buffer, 24c...FULL detector, 5...Block〇1st) 2nd Figure 3

Claims (1)

[Claims] In a facsimile machine equipped with an automatic repeat request device, when an error is discovered in a frame received by the automatic repeat request device at the time of reception, or when the facsimile device is equipped with the data of a frame correctly received from the receiving automatic repeat request device, A facsimile device characterized in that a retransmission request is made when an output cannot be output.