JPH09163023A - Data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a proper communication speed without the occurrence of fall back even in the case of generation of a charging pulse during the training sequence. SOLUTION: This data communication equipment is connected to the data communication network using the public line provided with a charging function which transmits the charging pulse at intervals of a prescribed time unit to perform the charging processing; and when a training pattern having a prescribed communication speed transmitted through the data communication network and the charging pulse are simultaneously received (S5: YES), a data request means requests reexecution of training with the training pattern having the same communication speed (S6 and S8).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication apparatus which is connected to a public line and receives a charging pulse for a usage fee in data communication, and in particular, an appropriate communication speed can be set without being affected by the charging pulse. Data communication device.

[0002]

2. Description of the Related Art In a data communication apparatus, after connecting to a communication line, a communication speed (bit rate) is set with a communication partner to determine the number of characters and words that can be transmitted and received in a predetermined time according to the line quality. Has been. Then, when setting the communication speed, the following training sequence processing is performed by the fallback function in order to enable data communication at an optimum communication speed than ever before.

For example, when a modem having a communication speed of 9600 bps (bits / second) performs a training sequence, training data of a predetermined pattern (hereinafter referred to as "training pattern") is initially transmitted at 9600 bps. It Then, the receiving side compares the transmitted training pattern with the data of the pattern determined by the receiving side. Therefore, the presence or absence of an error is confirmed by both data, and the data indicating whether or not the communication is possible at the communication speed of 9600 bps is returned to the transmitting side.

Therefore, if the communication at the communication speed is possible, the subsequent data communication will be performed at this 9600 bps. On the other hand, if the error rate is high and communication is impossible, fallback is executed, and for example, 720
The training sequence is continuously executed by reducing the communication speed to 0 bps. Therefore, the training pattern of the predetermined communication speed is transmitted again, and the data of the pattern determined by the receiving side is compared. Then, similarly, it is confirmed whether communication is possible, and the data is returned to the transmitting side. In this way, the fallback in which the communication speed is sequentially reduced and the processing is repeated is repeated until the optimum communication speed is determined, and the training sequence is executed.

[0005]

By the way, a public line is used for data communication, and there is a so-called pink telephone line. This is used for a so-called pink telephone in which a fee-charging process is performed by receiving a fee-charging pulse transmitted every predetermined time unit set when the line is used, and the fee is managed. Therefore, in a facility where such a pink telephone is used, when trying to use a public line, the pink telephone line having a charging function is used.

However, when data communication is performed using such a pink telephone line, if a charging pulse occurs during the training sequence described above, a communication error occurs due to the influence of the charging pulse. I may end up doing it. Therefore, there is a problem that fallback is executed even though the line quality is a good communication speed, and a low communication speed is set. In this way, if the line quality is good at the prescribed communication speed and the communication speed falls back to a lower communication speed, the amount of information per unit of time that would otherwise be able to be communicated cannot be transmitted, and the communication capability Will be inferior to. Therefore, the time required for data communication becomes long, and the usage fee also increases accordingly.

Therefore, in order to avoid the above inconvenience, the present invention provides a data communication device capable of setting an appropriate communication speed without causing a fallback even when a charging pulse occurs during a training sequence. With the goal.

[0008]

A data communication device of the present invention is connected to a data communication network using a public line having a charging function for performing a charging process by transmitting a charging pulse every predetermined time unit. In the case where training pattern data of a predetermined communication speed transmitted via the data communication network and a charging pulse are received at the same time, data requesting execution of training with training pattern data of the same communication speed again. It is characterized by having request means.

In the data communication apparatus of the present invention having the above configuration, a training sequence is performed to set the communication speed when using the line of the data communication network.
At that time, since the optimum communication speed is set, fallback is executed for a training pattern in which communication is impossible due to a high error rate. On the other hand, since the data communication device receives the charging pulse every predetermined time unit, if the charging pulse is received over the training pattern even if the communication speed is appropriate, it is judged as an error and the fallback is executed. Will be done. Therefore, when the charging pulse is received at the same time as the training pattern during the execution of the training sequence, the data requesting means again requests the execution of the training with the training pattern of the same communication speed, and it is appropriate without causing fallback. It is possible to set various communication speeds.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a data communication device according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a data communication device of the present invention. The data communication device 1 according to the present embodiment is the above-mentioned pink telephone line (hereinafter simply referred to as “public line”) that is a public line.
It is connected to a charging pulse generating device 18 in the telephone exchange 17 which transmits a charging pulse every predetermined time unit.

As shown in FIG. 1, the data communication device 1 includes a CPU 11 which is a central control unit as data requesting means.
RAM 12 and ROM 1 for the CPU 11
3, a modem 14, an NCU 15, and a charging pulse detecting circuit 16 as a charging pulse detecting means are connected and configured. The ROM 13 stores an operation program of the CPU 11 that controls the operation of the data communication device 1.
In particular, a data request program 131 in a training sequence described later is stored. And RA
M12 forms a work area of the CPU 11 that operates according to each program stored in the ROM 13.

Further, the modem 14 communicates data with the modem on the other end of the communication via the public line. The NCU 15 connects / disconnects a line to / from a public line and dials when the modem 14 transmits / receives data. Further, the charging pulse detection circuit 16
Then, the presence or absence of the charging pulse transmitted from the charging pulse generator 18 to the data communication device 1 is detected at any time.

Next, the operation of the data communication apparatus 1 of the present embodiment, particularly the training sequence will be described.
FIG. 2 is a diagram showing a flowchart of the training sequence. First, a dial pulse or dial tone signal is transmitted from the data communication device 1 via a public line. That is, the public line is opened by the off-hook of the data communication device 1, and a predetermined communication partner is designated by the dial operation (S1). Then, the own station and the partner station are confirmed based on the dial number by tone and ID exchange (S2), and a dedicated communication line is created.

After that, a training sequence is executed so that transmission and reception can be performed at an appropriate communication speed (S3).
Therefore, in the data communication device 1, the modem 14 and the NCU 15 are controlled on the basis of the call request from the personal computer or the like, and the modem 14 receives the training pattern of, for example, the communication speed of 9600 bps transmitted from the communication partner. Also,
When the training sequence is started, the charging pulse detection circuit 16 also starts to operate, and the charging pulse generator 1
The arrival of the charging pulse transmitted from 8 is checked.

Then, when the training pattern of the predetermined communication speed is received, it is confirmed whether or not the training pattern includes an error (S4). If the communication speed is appropriate and no error is confirmed by the training pattern (S4: NO), the CPU 11
Thus, the training result "Training completed" is set in the RAM 12 (S11). Then, the training result at the communication speed is transmitted to the communication partner.

On the other hand, if an error is confirmed by the training pattern at the communication speed (S4: YES)
The following control is executed by the data request program 131 of the ROM 13. First, the charging pulse detection circuit 16 of the data communication apparatus 1 determines whether the charging pulse is transmitted from the charging pulse generator 18 while the data communication apparatus 1 is receiving the training pattern at the predetermined communication speed in S3. It is determined whether or not it is detected (S5).

As a result, when the billing pulse detection circuit 16 detects the billing pulse (S5: YES), the information "retrain at the same speed" is set in the RAM 12 as a training result (S6). Further, when the charging pulse is not detected (S5: NO), the information of “fallback and retrain” is similarly set as the training result (S7). Therefore, in the former case, the training pattern with the same communication speed as the previous time is received, and in the latter case, the training pattern with the communication speed one step lower is received.

In this way, after the data communication apparatus 1 confirms the predetermined communication speed, the training result at the communication speed is transmitted to the communication partner in any case (S8). Therefore, the data communication device 1 on the calling side
Then, the next training pattern based on the transmitted training result is received (S9). However, considering that some error such as a charging pulse occurs during transmission of the training result, whether the training pattern was actually received or not. Is confirmed (S10).

Therefore, when the training pattern cannot be received (S10: NO), the data communication device 1
It is determined that an error due to a charging pulse or the like occurred while the training result was being transmitted from, and the training result was not transmitted to the communication partner. So again S6 or S
The training result set in 7 is transmitted from the data communication device 1 to the communication partner (S8). On the other hand, when it is confirmed that the data communication device 1 has actually received the training pattern (S10: YES), the process returns to S4 and S
Whether or not there is an error in the training pattern received in 9 is confirmed. After that, when the final training result is set (S11), the training result is transmitted to the communication partner (S12), and the training sequence ends.

Therefore, in the data communication apparatus of the present embodiment, as shown in the sequence diagram of FIG. 3, in the training sequence, the data communication apparatus 1 which is the calling side is the training pattern from the communication partner who is the called side. Even if a charging pulse is received during reception, by confirming it as an error and requesting training data at the same communication speed again, the optimum communication speed setting that is not affected by the charging pulse can be set. It has become possible.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, RO
Although only the M13 data request program 131 is shown, it naturally has other control programs necessary for data communication.

[0022]

The data communication apparatus of the present invention uses the public line in which the charging pulse is generated, and when the training pattern of the predetermined communication speed to be transmitted and the charging pulse are received at the same time, Since it has a data requesting means for requesting training to be performed again with a training pattern of the same communication speed, it will not fall back even if it is an appropriate communication speed, and an appropriate communication speed can be set. It has become possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a data communication device.

FIG. 2 is a diagram showing a flowchart of the operation of the data communication device.

FIG. 3 is a communication sequence diagram between a data communication device and an information center.

[Explanation of symbols]

 11 CPU 13 ROM 16 Billing pulse detection circuit 18 Billing pulse generator 131 Data request program

Claims (1)

[Claims] 1. A data communication apparatus connected to a data communication network using a public line having a charging function for performing a charging process by transmitting a charging pulse every predetermined time unit, and transmitting via the data communication network. When the training pattern data of the predetermined communication speed and the billing pulse are received at the same time, the data communication device further comprises a data requesting means for requesting the execution of the training with the training pattern data of the same communication speed. .