JPH0432336A - Modem changeover system - Google Patents

Abstract

PURPOSE:To reduce the time up to a fault restoration by switching the connection of a communication line and a data terminal equipment from a 1st MODEM to a 2nd MODEM when a fault of the 1st MODEM is discriminated based on a preset fault discrimination condition. CONSTITUTION:When an RS(Request to Send) signal is set to a setting section 13, a CS(Clear to Send) signal is not set. Moreover, it is preset that a MODEM 2 is faulty if no carrier signal is sent. Furthermore, a control section 14 operates switches 7-10 to connect a communication line 6 and a data terminal equipment 5 to the MODEM 2. Then a line signal monitor section 11 monitor a line interface signal and a DTE signal monitor section 12 monitor a DTE interface signal to send the result to the control section 14. Moreover, when the conditions set to the setting section 13 are satisfied, the control section 14 operates switches 7-10 to select the connection of the communication line 6, the data terminal equipment 5 and the MODEM 2 into the connection of the communication line 6, the data terminal equipment 5 and a MODEM 3. Thus, the time till fault restoration is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a modem switching system, and more particularly to a modem switching "apparatus" for switching a modem to a standby modem.

[Conventional technology]

Conventionally, when a failure occurs in the first modem, the person operating the data terminal equipment contacts a maintenance center, etc., and a maintenance worker visits the site with a replacement modem and performs the replacement work. was.

[Problem to be solved by the invention]

The above-described conventional modem switching method has the disadvantage that it takes a lot of time after a failure occurs in the modem until it is replaced with a replacement modem.

[Means to solve the problem]

The modem switching method of the present invention includes operational and standby first and second modems that are connected to a communication destination modem and a data terminal device via a communication line, and The first modulation/demodulation is performed based on a failure determination condition of the first modulation/demodulation device set in advance for the line interface signal and the DTE interface signal while monitoring the line interface signal for the communication line and the DTE interface signal for the data terminal device. and a modem switching device that switches the connection between the communication line and the data terminal device from the modem]-th modem to the second modem when it is determined that the device is malfunctioning.

The robust modem switching system of the present invention sets the failure judgment condition to the R8 signal indicating a request for transmission of the DTE interface signal from the DTE, the C8 signal indicating the modem's acceptance of the request, and from the modem to the communication line. It has a configuration that depends on the presence or absence of coexistence of transmitted carrier signals.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. The embodiment shown in FIG. 1 includes a modem switching device 1, an operational modem 2, a standby modem 3, a communication destination modem 4, and a data terminal equipment (DTE) 5. It consists of

The modem switching device 1 includes a switch 7.8 for switching connections between the communication line 6, the modem 2, and the modem 3, and a data terminal device 5, the modem 2, and the modem 3.
A switch 9.10 that switches the DTE (Data Terimal) between the data terminal device 5 and the modem device 2
a DTE signal monitoring unit 12 that monitors the interface signal; a setting unit 13 that sets conditions for the line interface signal and DTE interface signal under which the communication line 6 and the modulation/demodulation device 2 should be regarded as faulty;
It has a control section 14 that controls these. In the above configuration, the operation of detecting a failure in the modem 2 in the modem switching device and switching the connection between the communication line 6, the data terminal device 5, and the modem 2 to the modem 3 will be described below.

- When fishing on a boat, the modulator/demodulator transmits an RS (
If the Request to 5end) signal is on,
In response, the modulator and demodulator sends C S (C1ear t) to the data terminal device indicating acceptance of transmission.

5end) The signal is turned on and the carrier signal is sent from the modulation/demodulation device to the communication line, so if the C8 signal is not turned on or the carrier signal is not sent out when the RS signal is on in the setting section 13, the modulation/demodulation device 2 failure is set in advance. The control section 14 operates the switches 7.8 and 9.10 to connect the communication line 6 and the data terminal device 5 to the modulation/demodulation device 2. The line signal monitoring section 11 monitors the line interface signal, and the DTE signal monitoring section 12 monitors the DTE interface signal, and transmits the results to the control section 4. When the conditions set in the setting unit 14 are satisfied, the control unit 14 operates the switches 7, 8, 9, and 10 to connect the communication line 6, the data terminal device 5, and the modem device 2.
The connection with the modem is switched to the modem 3.

By the above method, a failure in the modem 2 is detected in the modem switching device 1, and the communication line 6 and the data terminal device 5 are detected.
The connection of the modem 2 can be switched to the modem 3.

〔Effect of the invention〕

As explained above, according to the present invention, even if data communication cannot be performed due to a failure of the modem while data communication is being performed with a host computer, etc. through a data terminal device or communication line, a replacement device is automatically installed. This has the effect of significantly shortening the time it takes to recover from a fault.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Modulation/demodulation device switching device, 2.3.4...Modulation/demodulation device, 5...Data terminal device, 6...Communication line, 7
．． 8.9.10... Switch, 1]... Line signal monitoring section, 12... DTE signal monitoring section, 13... Setting section, 14... Control section.

Claims (1)

[Scope of Claims] 1. An operational and standby first unit that connects to the modem and demodulator of the communication destination via a communication line and also connects to the data terminal device.
and a second modem, and the first modem configured in advance for the line interface signal and the DTE interface signal while monitoring the line interface signal for the communication line of the first modem and the DTE interface signal for the data terminal equipment. A modem device that switches the connection between a communication line and a data terminal device from the first modem device to the second modem device when a failure of the first modem device is determined based on a failure determination condition of the modem device. 1. A modem switching system comprising a switching device. 2. The failure determination condition is the presence or absence of the coexistence of an RS signal indicating a transmission request from the DTE of the DTE interface signal, a CS signal indicating acceptance of the request by the modem, and a carrier signal sent from the modem to the communication line. A modem switching system characterized in that: