JPH0244430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a facsimile transmitter, and more particularly to a transmission control system for a facsimile apparatus having an error retransmission function.

In a conventional facsimile transmitter having an error retransmission function, as shown in FIG. After the retransmission request signal is received by the detection circuit 5 and the signal is detected by the detection circuit 5, the facsimile data is retransmitted again by a certain predetermined time T.
That is, in the conventional error retransmission method, the procedure shown in FIG. 2 is such that when the facsimile signal a from the transmitter l side is mistaken, the receiver f side sends back a retransmission request signal b. When the transmitter l side detects the retransmission request signal b, it goes back a certain fixed time (T time) d and retransmits the facsimile data from that point onwards.

In this method, the T time for retroactive retransmission is fixed, but depending on line conditions and usage patterns, the time from when erroneous facsimile data is sent to when a retransmission request signal is detected on the sending side is not constant. Therefore, there was a drawback that some of the erroneous data could not be retransmitted, or even the correct data could be retransmitted, resulting in wasted time.

An object of the present invention is to provide a transmission procedure for a facsimile transmitter having an error retransmission function, and to calculate the time required from sending erroneous data to detecting a retransmission request signal before sending out facsimile data for each line or type of use.
By measuring and storing the time, if a retransmission request signal is received during actual facsimile transmission, t
To provide a facsimile transmitter having the most efficient error retransmission method by retransmitting facsimile data from a point back in time.

According to the present invention, an error data sending circuit has a function of sending intentionally erroneous data before sending facsimile data, a retransmission request signal detection circuit that detects a retransmission request signal in a signal from the other party, A facsimile transmitter comprising a time measurement memory circuit having a function of measuring time t from sending out the intentionally erroneous data to detecting the retransmission request signal and a function of storing the time t. can get.

Embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows a facsimile transmitter according to an embodiment of the present invention, and FIG. 4 shows a facsimile transmission procedure according to an embodiment of the present invention.

3 and 4, in this embodiment, if the error data sending command 10 is enabled prior to sending out the facsimile data signal a', the analog gate 8 becomes conductive, the analog gate 9 becomes non-conductive, and the error data sending circuit The deliberately falsified data g from 6 is transmitted through modulator 2' onto line 3'. At the same time, the error data sending command instructs the time t measurement storage circuit 7 to start measuring time t.

The other party's device connected to line 3' (not shown)
From f', a retransmission request signal b' is returned as a response signal for the error data g. On the transmitter side, a retransmission request signal b' passes through a line 3' and a demodulator 4' and is input to a retransmission request signal detection circuit 5'. When this retransmission request signal detection circuit 5' detects the retransmission request signal b', it instructs the t time measurement storage circuit 7 to end the time measurement and to store the measured time h.

Next, when the facsimile type device l' invalidates the error data sending command 10, the analog gate 8 becomes non-conductive, the analog gate 9 becomes conductive, and the facsimile data signal a' from the facsimile data sending circuit 1' is modulated. It is sent to line 3' through device 2'. When the other party's device f' detects an error in the facsimile data signal a', it returns a retransmission request signal b', passes through the line 3' and the demodulator 4', and sends it to the facsimile device l'. do. Here, when the facsimile device l' detects the retransmission request signal b', it instructs the facsimile data sending circuit 1' to retransmit the data by the time h stored in the time measurement storage circuit 7. Therefore, the facsimile data transmitting circuit 1' retransmits the facsimile data from h hours ago, but this is nothing but retransmitting the data from the erroneous data until the retransmission request signal is received.

That is, in this embodiment, the minimum necessary amount of data is retransmitted, and error retransmission can be performed efficiently and reliably. Moreover, in this embodiment, since the measurement of time t is performed every time the line conditions or usage patterns differ, optimal retransmission can be performed regardless of the line conditions or the like.

As explained above, the present invention measures and measures t time every time line conditions or usage patterns are updated.
Since the data is memorized, the optimal amount of data is always retransmitted, which overcomes the traditional drawbacks of wasting time and retransmitting incomplete erroneous data, making it possible to retransmit erroneous data more efficiently and reliably. It is.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a facsimile device using a conventional error retransmission method, FIG. 2 is a diagram showing a transmission procedure using a conventional error retransmission method, and FIG. 3 is a diagram showing a facsimile transmitter in an embodiment of the present invention. Figure, 4th
The figure is a diagram showing a transmission procedure according to an embodiment of the present invention. 1, 1'...facsimile data transmission circuit, 2,
2'...Modulator, 3,3'...Line, 4,4'...
Demodulator, 5, 5'...Retransmission request signal detection circuit, 6
...Error data sending circuit, 7...T time measurement storage circuit, 8, 9...Analog gate, 10...Error data sending command, 11...Inverter, a, a'...
...Facsimile data signal, b, b'...Retransmission request signal, c, c'...Retransmission data signal, d...T time (fixed time), l, l'...Transmitter side, f,
f′...receiver side, g...deliberately erroneous data,
h...t time (time by measurement).

Claims (1)

[Claims] 1. erroneous data sending means having a function of sending intentionally erroneous data before sending facsimile data; retransmission request signal detecting means for detecting a retransmission request signal in a signal from the other party's device; a function of measuring the time (t time) from when the set data is sent to when the retransmission request signal is detected;
t time measuring storage means having a function of storing the t time, measures and stores the t time before transmitting the facsimile data, and when the retransmission request signal is detected during the facsimile data transmission, the t time is measured and stored. A facsimile transmitter characterized by being able to retroactively retransmit facsimile data.