JP2695443B2 - Modem automatic switching system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to an automatic modem switching system for automatically switching between modems, where a center or the like has a plurality of types of modems, and a training signal corresponding to these modems is sequentially transmitted to send a response signal from a user side ( (Training signal) and automatically switching between modems for communication, has multiple types of modems with different transfer rates and modulation methods, and generates training signals corresponding to these modems. A circuit, a switching circuit that selects one of the training signals generated by these training generation circuits and sends it to the line, and a time to monitor the time during which the training signal is sent to the line via this switching circuit In response to sending the training signal to the line via the monitoring unit and this switching circuit, And a training determination circuit for determining whether or not a response signal (training signal) corresponding thereto is received from the caller side, and the training signal is sent via the switching circuit on the callee side in correspondence with the line connection from the caller side. Is sent to the line, and when the training signal is transmitted by the training determination circuit before the time monitoring unit times out, data transmission / reception is started using the modem corresponding to the training signal. When the corresponding training signal is not received, the switching circuit is switched to sequentially send other training signals to automatically perform modem switching.

[Industrial applications]

The present invention relates to a modem automatic switching system for automatically switching modems.

In the world of switched line modems, various speed and modulation types are currently used. It is desired to automatically switch these modems according to the modem on the other side.

[Problems to be solved by conventional technology and invention]

Conventionally, as shown in FIG. 3, when a host of a center and a plurality of users A, B, etc. perform data communication using a plurality of types A, B, etc. of modems via a switched line, for example, by telephone. A telephone number is assigned to each modem, such as a type A modem for the number X and a type B modem for the telephone number Y. Therefore, users A and B need to recognize the telephone number corresponding to their own modem type, connect to the corresponding modem A, and perform communication (such as personal computer communication) with the host. However, there was a problem that the management of the type of modem was complicated and troublesome.

The present invention has a plurality of types of modems in a center or the like, sequentially transmits training signals corresponding to these, determines a response signal (training signal) from the user side, and automatically switches the modems for communication. It is an object.

[Means to solve the problem]

 Means for solving the problem will be described with reference to FIG.

In FIG. 1, the training generation circuit 1 generates a training signal peculiar to a modem.

The switching circuit 3 selects one from a plurality of types of training signals and sends it to the line.

The time monitoring circuit 4 monitors the time during which the training signal is sent to the line.

The training determination circuit 5 determines, in response to the training signal selected by the switching circuit 3 and transmitted to the line, whether or not a response signal (training signal) indicating that the training signal has been recognized is received from the other party. To do.

[Action]

According to the present invention, as shown in FIG. 1, the switching circuit 3 selects one from the training signals generated by the training generation circuit 1 and corresponding to a plurality of types of modems, and sends it to the line. Correspondingly, when the training determination circuit 5 determines that the response signal (training signal) from the other party has been received, data communication is performed using the modem corresponding to the transmitted training signal. On the other hand, when the training determination circuit 5 does not receive a response signal from the other party and the time monitoring circuit 4 determines that the training signal has been transmitted for a predetermined time (time-out), the switching circuit 3 is switched to another. Training signals are sequentially transmitted to the line, and data communication is performed using the modem which receives the response signal.

Therefore, it is possible to have a plurality of types of modems, sequentially send the training signals corresponding to these modems to the line, and automatically switch to the modem to which the response signal is received from the other side for data communication.

〔Example〕

Next, the configuration and operation of one embodiment of the present invention will be sequentially described in detail with reference to FIG. 1 and FIG.

In FIG. 1, a modem (type A) and a modem (type B) are different types of modems, such as CCITT.
It is a modem compatible with the recommended V.22 (1200bps), V21 (300bps), etc. These modems include a training generation circuit 1 that generates a training signal peculiar to the modem prior to data communication, a modulation circuit 2 that modulates data, and the like.

The switching circuit 3 selects one of the training signals generated by the training generating circuit 1 of the modem and sends it to the line. Further, when a compatible modem is found with the other party, the signal modulated by the modulation circuit 2 of the found modem is sent to the line.

The time monitoring circuit 4 monitors the time of the training signal sent to the line via the switching circuit 3, and when the time is over, switches the switching circuit 3 to send another training signal to the line. is there. Timer 4-
1 is for counting time.

The training determination circuit 5 determines whether or not a response signal (training signal) is received from the other party in response to the training signal sent to the line via the switching circuit 3. If it is determined that the modem has been received, it means that a modem corresponding to the training signal sent to the line has been found, and thereafter, this modem is used to perform data communication with each other.

 The control unit 6 performs various controls.

Next, the operation of the configuration of FIG. 1 will be described in detail with reference to FIG.

FIG. 2 (a) shows the operation when the systems are the same.

In FIG. 2A, training A is sent to the calling side. This means that the training A (training signal A) generated by the training generation circuit 1 of the receiving side modem (time A) shown in FIG. 1 sent from the calling side is sent to the line through the switching circuit 3. I mean.

Responds to the fact that the calling side receives and detects the training signal sent to the line, and transmits training A to the called side. This means that the calling side detects the training A (recognizes that it matches the modem of the calling side), and sends the recognition to the called side as training A.

, Send and receive data to and from each other by full-duplex communication.

As described above, when the modem on the receiving side and the modem on the transmitting side match, the training signal can be exchanged and the data communication can be started immediately.

FIG. 2B shows the operation when both methods do not initially match.

In FIG. 2B, training A is sent to the calling side. This means that the training circuit 1 of the modem (type A) shown in FIG. 1 on the called side, which is called from the calling side, is sent to the line via the switching circuit 3.

Indicates a time-out condition. This is because when training A is sent to the line via the switching circuit 3,
FIG. 1 shows a state in which the time monitoring circuit 4 activates the timer 4-1 and the training determination circuit 5 does not receive a response signal from the transmission side and the timer 4-1 times _out (passes the time T _out ). .

Sends training B. This means that the switching circuit 3 is switched in response to the time-out at, and the training B generated by the training generating circuit 1 of the modem (type B) is sent to the line via the switching circuit 3. I mean.

Responds to the fact that training B transmitted to the line is received and detected by the calling side, and training B is transmitted to the called side. This means that the calling side has detected the training B (recognizing that it matches the modem held by the calling side), and therefore transmits the recognition result as the training B to the called side.

, Send and receive data to and from each other by full-duplex communication.

As described above, when the modem on the called side and the modem on the calling side do not initially match each other, the time-over is used as a trigger to repeat the sequential transmission in the mode of switching to the training signal of the next type of modem, and the modem By performing data communication with each other at the time of matching, it becomes possible for the receiving side (center side) to match with one type of modem held by the calling side (user side) for mutual data communication.

〔The invention's effect〕

As described above, according to the present invention, a plurality of types of modems are provided, training signals corresponding to these modems are sequentially transmitted to the line, and the modems that receive the response signal from the other side are automatically switched. Since a data communication configuration is adopted, for example, a center (incoming side) having multiple types of modems can automatically switch to a compatible modem with a user (outgoing side) who has only one type of modem to transfer data. Can communicate. As a result, the user can easily access the center without being aware of the modem.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of one embodiment of the present invention, FIG. 2 is an operation explanatory diagram of the present invention, and FIG. 3 is an explanatory diagram of a conventional technique. In the figure, 1 is a training generation circuit, 3 is a switching circuit, 4 is a time monitoring circuit, 4-1 is a timer, and 5 is a training determination circuit.

Claims (2)

(57) [Claims] 1. An automatic modem switching system for automatically switching modems in terminals to which different types of modems are connected, each of which has a plurality of types of modems having different transfer rates, modulation systems, etc., and each of the plurality of modems. A training generation circuit for generating a first training signal corresponding to the above, a switching circuit for selecting one of the first training signals generated by the training generation circuit and transmitting the selected training signal to a line, and an opposite terminal A training determination circuit for determining whether or not a second training signal corresponding to the first training signal to be transmitted has been received, one type corresponding to the line connection with the opposite terminal. The first training signal corresponding to the modem of is transmitted to the line and corresponds to the transmitted first training signal When the training determination circuit determines that the second training signal is received, data transmission / reception is started using the modem corresponding to the training signal, and the first training signal of the transmitted type is handled. If it is determined that the second training signal to be received is not received, the switching circuit is switched to send the first training signal corresponding to another type of modem to the line, and the second training signal from the opposite terminal is sent. Modem automatic switching method, characterized in that it judges whether or not the training signal has been received. 2. A modem automatic switching system, comprising: a time monitoring unit for monitoring a time during which a training signal is sent to the line via the switching circuit, and sending the first training signal to the line, When the second training signal corresponding to the first training signal sent by the training determination circuit is not received before the time monitoring unit times out, the switching circuit is switched to correspond to another type of modem. 2. The automatic modem switching system according to claim 1, wherein the first training signal is transmitted to the line.