JPH0376376A - Automatic equalizer setting system for training time - Google Patents

Abstract

PURPOSE:To execute satisfactory facsimile communication without lowering communication speed by automatically connecting a suitable equalizer while receiving a training check signal TCF three times when a line state is adverse. CONSTITUTION:At the time of G3 reception, a reception side sends out a called station identification signal CED and a digital identification signal DIS after a call is incoming. Thus, a facsimile on a transmission side receives the DIS and sends out a digital instruction signal DCS and a training check signal TCS. The reception side receives the TCS and executes a training check. As a result, when there are a lot of data errors, a training fail signal FTT is not sent out but an equalizer (A) EQLA31 of an external equalizer 27 in a MODEM 25 is set. In such a way, the retry transmission of the TCF on the transmission side is waited, the TCF is received again and the training check is executed. When there are a lot of data errors, the FTT is not sent out but an equalizer (B)EQLB32 is set but the training check of the TCF, which is received again, is executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an equalizer automatic setting method when checking G3 facsimile training, and in particular, to an equalizer automatic setting method during training check that allows good facsimile reception without reducing communication speed. Regarding equalizer automatic setting method.

[Conventional technology]

G3 facsimile uses the telephone network to send one A4 size document.
Because it can transmit data in minutes, it has become popular mainly in offices.

Furthermore, as a transmission control procedure for G3 facsimile, a binary procedure is used in which a high-level data link control frame structure is adopted and error detection is performed using a frame check sequence.

That is, when the receiving side receives a call, it sends out a called station identification signal (hereinafter referred to as CED) indicating that it is connected to a non-telephone, and also sends out a digital identification signal (hereinafter referred to as DIS) to determine the resolution, paper size, etc. Notify attributes such as As a result, on the transmitting side, the terminal constants used for communication are specified by the digital command signal (hereinafter referred to as DC8) from the DIS, and the modem training signal and the training check signal (hereinafter referred to as TCP
) is sent. On the receiving side, when operation is established as a result of the modem training check, it responds with a reception readiness confirmation signal (hereinafter referred to as CFR), and on the sending side, the modem sends out a fax lonely signal, and when the transmission is completed, the procedure starts. Notification is made with an end signal (hereinafter referred to as EOP). Furthermore, when the receiving side receives a message normally, it sends a message confirmation signal (
It responds with a line disconnection signal (hereinafter referred to as DC).
(denoted as N) to proceed to the call disconnection procedure.

Note that, on the receiving side, if the result of the training check is that there are many data errors, a training failure signal (hereinafter referred to as FTT) is sent. In this case, on the sending side, F
When TT is received, for example, the initial TCP communication speed is 9.
If it is 600bps, lower it to 7200bps and use TCP
Send out.

In addition, the setting of the modem's external equalizer (equalizer) was performed by the operator during a communication test at the time of installation, and was set arbitrarily using a dip switch, etc., or was set according to frequently used points.

Regarding conventional facsimile communication methods, see, for example, ``Electronic Information and Communication Handbook (1988).

Edited by the Institute of Electronics, Information and Communication Engineers, [)ri, 2601-2619'
It is stated in

[Problem to be solved by the invention]

In the above-mentioned conventional technology, the cable equalizer is only adjusted at the time of installation, and if the line condition deteriorates significantly after several settings, the communication speed is lowered to perform image communication.

The purpose of the present invention is to solve these problems by automatically adding an external equalizer to the modem, and to provide an automatic equalizer during training that enables good communication without reducing communication speed. The purpose is to provide a setting method.

[Means for Solving the Problems] In order to achieve the above object, the automatic equalizer setting method during training of the present invention is a method for automatically setting an equalizer during training for a G3 facsimile machine having a modem and an external equalizer. T of
When a CP is received and there are more data errors than a predetermined value, FTT is not sent, the external equalizer is switched, and an appropriate equalizer is automatically set by receiving the TCP retry sent from the sending side. Select/connect to
It is characterized by receiving data.

[Operation] In the present invention, if there are many data errors as a result of training check of TCP from the sending side, FT
T is not sent, and a retry transmission from the sending side is received. At this time, switch the modem's external equalizer in three ways.

Therefore, while receiving TCP three times on the receiving side, an appropriate equalizer can be automatically connected, and communication can be performed without reducing the communication speed.

〔Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a G3 facsimile according to an embodiment of the present invention, and FIG. 3 is a block diagram of an external equalizer according to an embodiment of the present invention.

In the second (!I), 21 is a code decoding unit (COD EC
) 24 outputs the decoded reception signal as a hard copy, 22 is a reading section that converts the signal obtained from the original document into a binary signal by an image sensor, and 23 stores the signal sent from the reading section 22. 24 is a code/decoder (CODEC) that performs redundancy reduction encoding processing on the signals stored in the memory 23 and decodes the received signals; 25 is a modem; 26 is a control unit for the entire device. 27 is an equalizer, 28 is an input/output device (
Ilo), 29 is a network control unit (NCU) that controls communication with other facsimile machines connected via a communication network.

In this embodiment, as a result of a training check of TCP from the transmitting side, if there are many data errors, FTT is not sent and the equalizer 27 is connected. Thereby, the retry transmission from the sending side is received and an appropriate TCP is connected.

In addition, in Fig. 3, 31 is an equalizer (A) (EQ
LA), 32 is an equalizer (B) (EQLB), 33 is a switch (A) (SWA), 34 is a switch (B) (S
Wn). In addition, IOA and ■08 are CPU
A programmable control signal generated by 26.

In this embodiment, the equalizer 27 shown in FIG. 2 is switched to three stages. That is, first 5WA33 and 5WB34
Close the 0th order and put the equalizer 27 in the through state,
After receiving the IOA, open 5WA33 and connect EQLA31. Furthermore, by opening 5WB34 with ■OB, EQ
Connect LB32.

FIG. 1 is a flowchart showing the equalizer setting process in an embodiment of the present invention, and FIG. 4 is a sequence diagram showing the equalizer setting procedure in the embodiment of the invention.

In this embodiment, when receiving G3, the receiving side sends CED and DIS after receiving a call. As a result, the sending facsimile receives DIS and sends DO3 and TCP.

The receiving side receives the TCP (101) and performs a training check (102).

As a result, if there are many data errors, FTT cannot be sent and the EQLA31 of the external equalizer 27 of the modem 25
(103).

In this way, it waits for retry transmission from the TCF on the transmitting side, receives TCP again (104), and performs a training check (105).

As a result, if there are many data errors, the FTT is not sent as in the previous case, and the EQLB 32 of the external equalizer 27 of the modem 25 is set (106).

In this way, the received TCP training check is performed again (107, 108).

As a result, if there are many data errors, FTT is sent (109) and EQLA31 and EQLB32 are turned off (110).

Note that if the data error is less than a predetermined value, (102,
105, 108), sends CFR 111), and receives facsimile data.

In this way, even if the line condition is poor and there are many data errors, by switching the external equalizer 27 in three ways, it is possible to receive TCP at the same communication speed three times from the sending side, reducing the communication speed. It is possible to perform good image communication without causing any interference.

〔Effect of the invention〕

According to this embodiment, if the line condition is poor, it is possible to automatically connect an appropriate equalizer while receiving TCF three times, so that good facsimile communication can be performed without reducing communication speed. be able to.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing equalizer setting processing in an embodiment of the invention, FIG. 2 is a configuration diagram of a G3 facsimile in an embodiment of the invention, and FIG. The configuration diagram and FIG. 4 are sequence diagrams showing equalizer setting procedures in an embodiment of the present invention. 21: Printer, 22: Reading unit, 23: Memory. 24: code/decoder (C, 0DEC), 25: modem. 26: CPU, 27: Equalizer, 28: Input/output device (
1/○), 29: Network control unit (NCU), 31: Equalizer (A) (EQLA), 32: Equalizer (B) (
EQLB), 33: Switch (A) (SWA),
34: Switch (B) (SWB). Figure 1 TCP check FAX reception Figure OA OB

Claims (1)

[Claims] (1) In the equalizer automatic setting method during training of a G3 facsimile equipped with a modem and an external equalizer, if a training check signal is received from the sending side and the number of data errors exceeds a predetermined value, a training failure signal is sent. An equalizer for training, characterized in that the above-mentioned external equalizer is switched, the training check signal sent for retry is received from the transmitting side, the appropriate equalizer is automatically selected/connected, and the data is received. Automatic setting method.