JPS58171155A - System for testing circuit - Google Patents

Abstract

PURPOSE:To diagnose the normality between a center and each terminal in a circuit connected by a multi-drop means by adding a testing circuit to a circuit side interface for an MODEM in a general data communication terminal device. CONSTITUTION:When a multi-drop circuit is to be tested by detecting a communication trouble through some means during communication, a center device 100 separates an MODEM 102 logically and a test controlling device 103 indicates a test and actuates a test mode switching circuit 104. A test signal generating circuit 103-2 sends a test starting signal to a terminal station device 200 for a fixed period. In each terminal station device 204, a signal discriminating circuit 203-3 detects the test starting signal and a signal branching circuit 204 turns the mode to the test mode. In the center device 100, a test signal generating circuit 103-2 sends a test signal assigned to each terminal station device successively for a fixed period and then monitors a response signal from a response signal generating circuit 203-2 in the terminal station device and diagnoses the circuit state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to data communication systems, and particularly to a line test and diagnosis system for multi-drop connections.

Conventionally, in communication with multi-drop connected lines, 2
In the event of a communication failure, one method is to physically connect multiple terminals that are branched into two at all times, and if you attempt to control/monitor each terminal individually by remote control from the center, the modulation/demodulation equipment Perform the test by transmitting the test data via the test terminal, or have another tester physically disconnect the test terminal, for example by setting the terminal's Dinotal Luzopa, etc. There was a way to do a repeat test. However, the former method described above has the drawback that it is difficult to distinguish between two lines or the modem which is faulty, so-called hierarchical classification, and the latter method requires a tester and is time-consuming. .

An object of the present invention is to add a test circuit to the line side interface of the modem of a general data communication terminal device between a plurality of terminals connected to a center in a remote location. It is an object of the present invention to provide a system that separates the modulation/demodulation level and hierarchy of normality between terminals and allows testing by remote control from a center.

According to the present invention, a communication system includes a center device and at least one terminal device subordinate to the center device and connected to the same line.

The center device issues test start and end signals in common to a control unit that instructs a single line test and receives the test results, and the terminal device, and selectively sends test signals individually assigned to the terminal device. a test signal generation circuit that generates a test signal; and a test signal detection circuit that detects a response signal corresponding to the test signal from the terminal device.

Each terminal device is equipped with a test mode switching circuit that separates general communication and test communication, and each terminal device has a signal branching circuit that branches signals between general communication and test communication, and a signal branching circuit that branches signals between general communication and test communication, and a signal branching circuit that branches signals between general communication and test communication, and A line test system is obtained which includes a signal circuit for receiving and identifying the test signal, and a response signal generation circuit for issuing the response signal to the center device.

In the present invention, when a communication abnormality is detected by some means and the line is tested, the center device logically disconnects the modem, issues a test instruction to the control unit, and activates the test mode switching circuit. next.

The test signal generation circuit sends a test start signal to the terminal equipment for a certain period of time. Each terminal device detects the test start signal with a signal identification circuit, and shifts to a test mode with a signal branch circuit. Next, the center device.

After the test signal generation circuit sequentially transmits the test signal assigned to each terminal device for a certain period of time, the response signal from the response signal generation circuit of the terminal device is monitored to diagnose the two-line state. When the diagnosis of the line status of all end station devices is completed, the center device sends a test end signal common to all end station devices for a certain period of time,
Switch the terminal equipment back to general communication mode. Thereafter, the test mode switching circuit is restored in the center device under the control of the control section.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram showing a connection form between a center device and a terminal device according to the present invention, in which a plurality of terminal devices 200 and 300 are connected to a center device 100 via a line branching device 500. There is. In this embodiment, a facsimile machine using a four-wire high-level data link transmission control procedure is used as the terminal equipment.

The center equipment can be roughly divided into the central processing unit 101, and the terminal equipment includes the terminal equipment 201, 301.4-wire modulation/demodulation equipment 2.
02,302. It consists of a test circuit 203°: 303 and signal branch circuits 204, 304.

FIG. 2 is a block diagram showing the configuration of an embodiment of the center device according to the present invention.

If a line test is requested due to some kind of failure during communication, the center device 100 inputs a line test command for the line to a tie writer attached to the central processing unit 101. The central processing unit 101 uses the command to issue a line disconnection command to the terminal equipment connected to the line, and sends the R8 signal O to the modem unit 102.
Perform FF.

The terminal device receives the line disconnection signal and enters the initial state upon detection of the CD signal OFF.

Next, in the center device 100, the test control device 103 operates a relay to set the test mode in response to an instruction from the central processing device 101, and switches the switching circuit 104 to the test control device 103 as shown by a broken line.

Next, in the test control device 103, under the control of the central processing unit 101, the control circuit 103-1 instructs the test signal generation circuit 103-2 to send out a test start signal common to each terminal connected by multiple terminals. do.

In this system, the test signal used was a standard PBMF signal used in general push-button telephones, as shown in FIG.

FIG. 3 is a block diagram showing the configuration of an embodiment of the terminal equipment according to the present invention.

In the terminal device 200, the test start signal is transmitted to the test circuit 203 via the branch amplifier 204-1 of the signal branch circuit 204. In the test circuit 203.

The signal identification circuit 203-3 identifies the test start signal, and notifies the test control circuit 203-1 to activate the relay, and switches the reception line switching circuit 204-3 to the termination circuit 20.
4-4, and the transmission line switching circuit 204-2.
is switched to the test circuit 203.

Next, in the center device 100, after transmitting the test start signal for a certain period of time and waiting at a certain timing interval, the test signal is sent to the first terminal device 200 which is branch-connected from the test signal generation circuit 103-2. Send time.

In the terminal device 200, as shown in FIG. 4, the signal identification circuit 203-3 detects a preset test signal for its own terminal, and notifies the test control circuit 203-1. When the test control circuit 203-1 receives the signal, it sends the response signal assigned to its own station to the center device @100 for a certain period of time via the response signal generation circuit 203-2.

In the center device 100, the test signal detection circuit 103-3 detects a response signal from the terminal device 200, and transmits the result to the central processing unit 101 via the test control circuit 103-1. At this time, if the center device 100 cannot normally receive a response from the terminal device 200 within a certain period of time, it times out and shifts to sending a test signal to the next terminal device (not shown).

When the test of all the terminal equipment accommodated on the same line is completed, the test control equipment 10 under the control of the central processing unit 101
3, a test end signal is sent from the test signal generation circuit 103-2 for a certain period of time. All terminal devices receive the test start signal and switch back to the general communication mode. Next, in the center device 100.

After a certain period of time has elapsed after sending the test end signal, the communication mode is switched back to normal communication mode.

In the above embodiment, the test signal and response signal of each terminal equipment were individually assigned, but by individually assigning only the test signal and sharing the response signal, nine terminal stations can be connected to one line. It can be accommodated until

As is clear from the above description, in the present invention, the multi-channel connected line is connected to a general-purpose P BMF sender/-
・It has the effect of being able to diagnose from a remote location using a simple method that combines

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing a connection form between a center device and a terminal device according to the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the center device according to the present invention, and FIG. FIG. 4 is a block diagram showing the configuration of an embodiment of the terminal equipment according to the invention, and FIG. 4 is a diagram showing an example of a test signal used in the embodiment of the invention. Explanation of symbols: 100 is a center device, 101 is a central processing unit, 102 is a modem device, 103 is a test control device, 10
3-'1 is a control circuit, 103-2 is a test signal generation circuit,
103-3 is a test signal detection circuit. 104 is a test mode switching circuit, and 200 is a terminal device. 201 is a terminal device, 202 is a modulation/demodulation device, 203 is a test circuit, 203-1 is a test control circuit, 203-2 is a response signal generation circuit, and 203-3 is a signal identification circuit. 204 is a signal branch circuit, and 204-1 is a branch amplifier. 204-2 is a transmission line switching circuit, 204-3 is a receiving line switching circuit, 204-4 is a termination circuit, and 300 is a terminal device. 301 is a terminal device, 302 is a modem, 303 is a test circuit, 304 is a signal branching circuit, and 500 is a line branching device. Figure 2 Figure 3

Claims (1)

[Claims] 1. In a communication system comprising a center device and at least one terminal device subordinate to the center device and connected to the same line, the center device performs a single line test. a control unit that gives instructions and receives the test results; and a test signal generation circuit that commonly issues test start and end signals to the terminal equipment and selectively issues test signals individually assigned to the terminal equipment. . Each of the terminal devices includes a test signal detection circuit that detects a response signal corresponding to the test signal from the terminal device, and a test mode switching circuit that separates between general communication and test communication, and each of the terminal devices includes: a signal branch circuit that branches signals between general communication and test communication; a signal identification circuit that receives the test start/end signal and identifies the test signal; and a response signal generation circuit that issues the response signal to the uplink device. A line test method equipped with