JP2756304B2 - Communication control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The transmission / reception of the modem is performed using the transmission speed information of the changed transmission speed from the modem and the data transmission speed information of the data transmitted / received to / from the modem. Regarding a communication control device that matches the data transfer rate of data, for the purpose of continuing normal data communication even if the line quality is degraded during data communication, it is not possible to automatically change the transmission or reception transmission rate. A communication control device for performing data communication with an opposing device via a modem capable of outputting a transfer speed information output unit for outputting data transfer speed information of data transferred to and from the modem; When there is a difference between these two pieces of speed information in response to the data rate information output from the unit and the transmission rate information for transmission or reception from the modem, the detection is performed. A detection unit that outputs a signal, and a data transfer rate for data transferred to and from the modem in response to the detection signal is matched with a transmission rate of the modem during data communication with the opposite device. And a control unit for performing the control.

[Industrial applications]

The present invention uses the transmission rate information of a changed transmission rate from a modem, and the data transmission rate information of data transmitted to and received from the modem to reduce the data transmission rate of the transmitted and received data to the transmission rate of the modem. The present invention relates to a communication control device for matching.

In a data communication network, data communication is performed by forming a line between data terminals and a partner data terminal via a telephone network. The line quality of the line is not only low when the line is set up, but may also deteriorate after the line is used. Since desired data communication cannot be performed with such low line quality, technical measures have been taken conventionally.

[Conventional technology]

In the case where the line formed with the partner data terminal via the conventional telephone network is a telephone line, in order to avoid being unable to enter normal data communication due to the deterioration of the line quality as described above, After releasing the line once set,
A technique has been used in which a call is re-established with the expectation that the line quality will be restored.

A conventional communication system in which data communication is performed by forming a line with a partner data processing device via its own communication control device, a modem, and a partner modem and a communication control device via a telephone network. In a data processing device, when performing data communication with a partner data processing device via a communication control device and a modem, when the line quality is poor and data communication at a desired transmission speed cannot be performed. ,
The following technical measures were taken: That is, if the modem is capable of making and receiving calls automatically under the control of the communication control device, if the transmission rate of the modem is changed by the fallback function activated during the automatic calling and calling sequence, the speed change is performed. The data rate at which information is communicated to the communication controller and transferred from the communication controller to the modem,
Change the data speed to match the notified speed change information,
Even if the line quality is degraded, normal data communication using the line can be started.

[Problems to be solved by the invention]

As described above, in the related art, before starting data communication, the transfer rate between the modem and the modem is determined by the fallback function, and the transfer rate between the modem and the communication control device is also determined by the fallback function. The speed is set so that the entire system transfers data at the same speed. Therefore, when the modem-to-modem transfer rate changes during data communication, the communication controller must recognize the change in the modem-to-modem transfer rate in order for the entire system to transfer data at the same rate. However, since the fallback function described above is a function added to the conventional communication procedure, the communication control device recognizes the data transfer rate only at the start of communication, and after the communication starts, the communication between the modem and the communication control device. The data transfer rate could not be changed. Therefore, if the line quality deteriorates after entering the data communication once, the above technical means will not be used, and the deterioration of the line quality will be caused by data retransmission (retry). When he got over the train and it was no longer valid, the line was forcibly released and an automatic recall was required or operator intervention was required.

The present invention has been created in view of such problems,
If the line quality deteriorates during data communication and the modem-to-modem transfer rate changes, normal data communication is continued by matching the modem-to-controller transfer rate with the modem-to-modem transfer rate. It is an object of the present invention to provide a communication control device which can be obtained.

[Means for solving the problem]

FIG. 1 is a block diagram showing the principle of the present invention. As shown in this figure, in a communication control device 4 for performing data communication with an opposing device via a modem 6 capable of automatically changing the transmission speed of transmission or reception, the communication control device 4 communicates with the modem 6. A transfer speed information output unit 8 for outputting data transfer speed information of data to be transferred, and the transfer speed information output unit 8
Data rate information output from the
A detecting unit 10 for outputting a detection signal when a difference occurs between these two pieces of speed information in response to transmission or reception speed information for transmission or reception from the modem 6;
A control unit (9, 11) for matching a data transfer rate for data transferred between the modem 6 and the modem 6 during data communication with the opposite device. .

[Action]

When data communication is normally performed with the opposite device, the data transfer speed of data transferred between the communication control device 4 and the modem 6 and the transmission speed of the modem 6 In a consistent state. Therefore, the detection unit 10
Does not output a detection signal.

When the line quality of the line formed between the remote device and the other device for the data communication deteriorates, the transmission speed information supplied from the modem 6 to the detection unit 10 is:
The data transfer speed of the data transferred from the communication control device 4 and the modem 6 output from the transfer speed information output unit 8 has a different value. Therefore, the detection unit 10
Outputs a detection signal to the processor 11. The processor 11 receives the detection signal, and the communication control device 4 and the modem 6
The data transmission / reception control unit 9 is operated so that the data transfer speed of the data transferred between the data transfer device and the modem 6 matches the transmission speed of the modem 6. During communication, even if the line quality deteriorates, the data communication can be continued.

〔Example〕

FIG. 2 shows an embodiment of the present invention. This embodiment is the third
It is an embodiment in a data communication network as shown in the figure. Modem 6 of FIG. 2 is a modem 6 _1, 6 ₂ of FIG. 3, the communication control device 4 is representative of a third view of the communication control device 4 _1, 4 _2. The modems 6 ₁ and 6 ₂ are connected to the telephone network 7 in FIG.
The communication control devices 4 ₁ and 4 ₂ are connected. Communication control device 4
_1, 4 _2, each of the data processing device 2 _1, 2 ₂ are connected.

In FIG. 2, a modem 6 is a modem having a fallback function. The modem 6 and the communication control device 4 are connected by a transmission timing line 20, a reception timing line 22, a transmission data line 24, and a reception data line 26. The transmission timing line 20 and the transmission data line 24 are connected to a transmission control unit 28. The reception timing line 22 and the reception data line 26 are connected to the reception control unit 30. A data bus 32 from a processor in the communication control device 4 is connected to the transmission control unit 28 and the reception control unit 30. The transmission timing line 20, the reception timing line 22, and the data bus 32 are connected to a timing change automatic detection unit.

 FIG. 4 shows the configuration of the timing change automatic detection unit 34.

Counter 36 receives a clock of 19.2 bps × 16 and 9600 bps
× 16 pulse train, 480bps × 16 pulse train, 2400bps × 16
And a pulse train of 1200 bps × 16 are output. The register 38 to which the data bus 32 is connected outputs a selection signal for selecting any one of the four pulse trains output from the counter 36 to the multiplexer (MPX) 40. The multiplexer 40 also receives a 19.2 bps × 16 clock. Data bus 32, register 3
8, the counter 36 and the multiplexer 40 correspond to the transfer speed information output unit 8 in FIG.

The output of multiplexer 40 is connected to the clock inputs of shift register 42 and shift register 44. The transmission timing line 20 is connected to the data input of the shift register. The reception timing line 22 is connected to the data input of the shift register 44. The eighth shift position of the shift register 42 and the transmission timing line 20 are exclusive OR circuits
Connected to 46. The eighth shift position of the shift register 44 and the reception timing line 22 are connected to an exclusive OR circuit 48. The output of exclusive OR circuit 46 is connected to the reset input of counter 50. The output of exclusive OR circuit 48 is connected to the reset input of counter 52. counter
Multiplexer 40 is connected to clock inputs of 50 and counter 52.
Output is connected. The carry outputs of the counters 50 and 52 are connected to an OR circuit 54. The transmission timing line 20, shift register 42, exclusive OR circuit 46, counter 50, reception timing line 22, shift register 44, exclusive OR circuit 48, counter 52, and OR circuit 54 correspond to the detection unit 10 in FIG. .

The operation of the present invention having the above configuration will be described below with reference to FIGS. Therefore, each component is used in the following description without adding a suffix 1 or 2 indicating the distinction between the transmitting and receiving terminals.

When the line quality of the line for the data processing device performing data communication is normal, the transmission speed of the modem is 9600 bps × 1, and the data transfer speed of the processor of the communication control device 4 is also 9600 bps × 1. ing. Transfer rate data indicating the data transfer rate of the processor of the communication control device 4 is set in the register 38 via the data bus 32 at the time of starting the data communication. From that register 38,
A selection signal for selecting a pulse train of 9600 bps × 16 (see (1) in FIG. 5) of the counter 36 is supplied to the multiplexer 40.
A pulse train of 9600 bps × 16 is supplied to 42 and the shift register 44.

Assuming that the data processing device is transmitting data to the partner data processing device, in this case, the transmission clock (see (2) in FIG. 5) is transmitted from the modem 6 via the transmission timing line 20 to the shift register 42. , The output pulse train appearing at the eighth shift position of the shift register 42 becomes a pulse train as shown in (3) of FIG. Accordingly, a pulse train as shown in FIG. 5 (4) appears at the output of the exclusive OR circuit 46. For each pulse of this pulse train, the counter 50 is reset before being counted up to a value representing its normal transmission speed (6 in the above circuit configuration), so that the carry signal is not generated from the counter 50 (fifth. As shown in (5) in the figure), the notification signal for changing the data transfer rate is not sent from the OR circuit 54 to the processor of the communication control device 4.

If the line quality during the communication deteriorates for some reason, the transmission speed of the modem 6 is changed to a lower transmission speed by the fallback function of the modem 6. When this change occurs, the transmission clock supplied to the transmission timing line 20 also becomes the transmission clock for the changed transmission speed. Then, as can be read from (2), (3) and (4) in FIG. 5, the reset pulse to the counter 50 at the time intervals as described above is not output from the exclusive OR circuit 46. Accordingly, a carry signal is generated from the counter 50, and a notification signal for changing the data transfer rate is sent to the processor of the communication control device 4 via the OR circuit 54. This notification signal is transmitted to the communication control device 4
Is used to change the data transfer rate transferred to the next processor to the data bus 32 from the processor to the next lower data transfer rate.

As a result, the corresponding transfer speed data is set in the register 38, and a pulse train of 4800 bps × 16 is supplied to the shift register 42 via the multiplexer 40. If the transmission clock supplied to the transmission timing line 20 changes the transmission speed due to the deterioration of the line quality, for example, 4800 bp
If s × 1 is performed (see (2) in FIG. 5), as apparent from the above description, the pulse train starts from the eighth shift position of the shift register 42 (see (3) in FIG. 5). Is output, a pulse train is similarly output from the exclusive OR circuit 46 (see (4) in FIG. 5). Therefore, the counter 50 is reset before the carry signal is output, and the notification signal is not output from the OR circuit 54. Conversely, if the change in the transmission rate has been made to a value lower than 4800 bps × 1, the notification signal is transferred to the processor of the communication control device 4 and transmitted from the processor to the data bus 32 in the same manner as described above. Used to change the transmitted data rate to the next lower data rate. Hereinafter, it is the same as the above.

When the data processing device 2 is receiving data via the modem 6 and the communication control device 4, the reception clock is supplied to the data input of the shift register 44 via the reception timing line 22; The exclusive OR circuit 46 is replaced by the exclusive OR circuit 48, and the counter 50
Same as described above, except that 52 is replaced.

Note that, instead of the transmission clock or the reception clock in the above embodiment, timing information indicating the clock may be received from the modem. The timing information,
Of data transferred from the processor of the communication control device 4
Alternatively, it may be used to detect a difference between the data received by the processor of the communication control device 4 and the data transfer speed information.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, even if the line quality deteriorates during normal data communication,
Normal data communication can be continued without hindering normal data communication due to the deterioration of the line quality. Communication time can be shortened, and communication costs can be reduced.

[Brief description of the drawings]

1 is a block diagram showing the principle of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram showing a telephone communication network embodying the present invention, and FIG. FIG. 5 is a diagram showing an example of the operation timing of the automatic timing change detection unit. 1 to 4, 2, 2 ₁ and 2 ₂ are data processing devices, 4, 4 ₁ and 4 ₂ are communication control devices, and 6,
6 ₁ and 6 ₂ are modems, and 8 is a transfer speed information output unit (data bus 3
2, register 38, counter 36 and multiplexer 40), 1
0 is the detection unit (transmission timing line 20, shift register 42,
Exclusive OR circuit 46, counter 50, receive timing line 22,
A shift register 44, an exclusive OR circuit 48, a counter 52, and an OR circuit 54).

Claims (1)

(57) [Claims] 1. A communication control device for performing data communication with a counterpart device via a modem capable of automatically changing a transmission speed of transmission or reception. A transfer rate information output section for outputting data transfer rate information; a data transfer rate information output from the transfer rate information output section; and both of these rates in response to transmission rate information for transmission or reception from the modem. A detection unit that outputs a detection signal when a difference occurs between information; and a data transfer rate for data transferred to and from the modem in response to the detection signal. A control unit that matches the transmission speed of the modem during communication.