JPS63133749A - Line supervisory equipment - Google Patents

Abstract

PURPOSE:To allow all terminals connected in parallel to detect anytime the line that the other terminal uses by supervising a voltage between two lines and detecting whether the line is used or not. CONSTITUTION:When line connection terminals 1a and 1b are connected to the line, a voltage supplied from a station is impressed on the terminals 1a and 1b. Resistances 14a, 14b and 14c divide the voltage, which enters a voltage detection circuit 15. When the terminal connected to the terminals 1a and 1b in parallel closes a loop to use the line, the voltage detection circuit 15 detects a drop in the voltage because the voltage between the terminals 1a and 1b falls, and transmits an output from an output terminal 16. Hence, by supervising the output 16, all the terminals can know whether the line is used or not.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a multi-line response device that sends messages to a large number of lines using one or more tape decks, for example, in which it is possible to determine which lines are connected. The present invention relates to a line monitoring device equipped with a line monitoring means for monitoring.

[Conventional technology]

An example of a conventional multi-line response device will be explained with reference to FIG.

In the figure, 1a to 1n are line connection terminals connected to a large number of telephone lines, and 2a to 2n are line connection terminals 1a to 1n.
It detects whether or not there is an incoming call, closes the line based on a command from a control circuit 5 (described later), connects the line to a tape deck 3 (described later), and determines whether the caller has hung up. Incoming call detection circuit to detect whether
3 is a tape deck for reproducing a message to be sent when the incoming call detection circuits 2a to 2n detect an incoming call; 4 is an automatic response switch for instructing whether or not to respond to an incoming call;
5 drives the tape deck 3 when the incoming call detection circuits 2a to 2n detect an incoming call, stops the tape deck 3 when the other party hangs up, or turns on/off the automatic answering switch 4. This is a control circuit that controls whether or not to drive the tape deck 3 in response to an incoming call depending on the off state.

Next, to explain the operation based on the above configuration, now,
When the automatic response switch 4 is in the OFF state, even if an incoming call is received at any of the line connection terminals 1a-1n and any of the incoming call detection circuits 2a-2n detects this, the control circuit 5 will not accept this incoming call. At the same time, the tape deck 3 is not driven.

On the other hand, when the automatic answering switch 4 is in the on state, when an incoming call is received at any of the line connection terminals 1a to 1n and any of the incoming call detection circuits 2a to 2n detects this, the line is closed to the incoming line. At the same time, the tape deck 3 is driven to reproduce the tape and send out a message.

By the way, with the multi-line response device described above, it is only possible to specify whether or not to automatically respond to all lines.
It was not possible to temporarily use some lines as regular telephone lines and use the remaining lines as auto-answers.

Therefore, in order to perform the above-mentioned use, a telephone is connected to the line via a changeover switch. and,
When making a call through the telephone, the switch is switched to connect the line to the telephone. However, the switch is switched while the line is closed and a message is being sent. In this case, the message is interrupted midway, causing an inconvenience. Therefore, it was necessary to monitor which lines were open.

Conventionally, there has been a device A shown in FIG. 5 that monitors the connection state of this line. This monitoring device A will be explained below. Note that the same reference numerals as in FIG. 5 indicate the same parts, and two line connection terminals are shown.

6a and 6b are connection terminals for the terminal device 12, which is a telephone;
a and 7b are connection terminals connected to the control circuit 5; 8a and 8b are line current detection terminals that connect the control circuit 5 and the line current detection circuit 9 that detects whether or not current is flowing through the line; 10a; , 10b are line switching terminals that connect the control circuit 5 and the relay 11. Note that the line current detection circuit 9 connects a pair of light emitting diodes 9a connected between the contact 11a of the relay 11 connected to the line connection terminal 1a and the terminal device connection terminal 6a, and the line current detection terminals 8a and Bb. This is a photocoupler consisting of a phototransistor 9b connected to the phototransistor 9b.

FIG. 6 is a block diagram in which the above-mentioned monitoring device A is connected to the telephone 12 and the control circuit 5. As shown in FIG.

The operation of this conventional example will be explained below. When the terminal 12 closes the line, current from the station flows through the station, the line connection terminal 1a, the contact 11a of the relay 11, and the light emitting diode 9as of the photocoupler 9. Since the signal flows through the terminal device connection terminal 6a, the terminal device 12, the terminal device connection terminal 6b, the line connection terminal 1b, and the station, the phototransistor 9b of the photocoupler 9 is turned on. Therefore, line current detection terminal 8a
.

Since the line 8b is short-circuited, the control circuit 5 knows that the line is being closed.

Then, when the terminal device 12 opens the line, the path is cut off and the phototransistor 9b is turned off, so that the line current detection terminals 13a and gb are turned off, and the control circuit 5 knows that the line is open. . Therefore, when the control circuit 5 uses the line, after confirming that the line current detection terminals 8a and 8b are off,
Relay 11 by passing current through line switching terminals toa and iob
The line is connected to the control circuit 5 by energizing the line and switching the contact 11a.

In addition, in the conventional example, the case where the terminal device 12 is one is shown, but when the terminal device 2 is plural, the seventh
Connect as shown.

[Problem that the invention seeks to solve]

By the way, in the conventional multi-line response device described above,
Only the control circuit 5 can tell whether the line is in use, and there is also the problem that the loop resistance to the game seen from the terminal 12 increases by the insertion of the photocoupler 9, and the line connection method Since the circuit is routed internally as shown in Figure 6, the circuit becomes complicated, and if the connection is made as shown in Figure 8, it can be detected when the subsequent line is in use, but it cannot be detected when the previous line is in use. there were.

[Purpose of the invention]

The present invention aims to solve the above-mentioned problems, and by monitoring the voltage between two lines of the line and detecting whether or not it is in use, all the terminals connected in parallel can be connected to other terminals at any time. To provide a line monitoring device that can detect whether a line is in use on a terminal device, does not increase the loop resistance of the terminal, and can be easily expanded by connecting a large number of terminals in parallel to the line. The purpose is to

[Summary of the invention]

The present invention aims to achieve the above-mentioned object, and its gist is that a voltage detection circuit for detecting changes in voltage is connected between two wires of a subscriber telephone line, and the output from the voltage detection circuit is When the voltage drops below a preset value, it is determined that the loop of the subscriber telephone line is closed, and when the voltage rises above the set value, it is determined that the loop is open.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIG.

Note that the same reference numerals as in FIGS. 4 to 7 above indicate the same parts, and explanations thereof will be omitted.

In the present invention, B is a line monitoring circuit, a rectifier bridge circuit 13 is connected between line connection terminals 1a and lb, and resistors 14a, 14b, 1 are connected to the output of this rectifier bridge circuit 13.
4C is connected, and a voltage detection circuit IS is connected to both ends of the resistor 14c.

The output terminal 16 of the voltage detection circuit 15 is connected to a terminal device.

Next, to explain the operation of the circuit shown in FIG. 1, when the line connection terminals 1a and lb are connected to the line, the voltage supplied from the station (usually 4
8v) is applied. This voltage is applied to the resistors 14a, 14b,
14c and input to the voltage detection circuit 15, where the voltage detection circuit 15 sets the resistance values of the resistors 14a, 14b, and 14c so that the divided voltage does not produce an output. be.

When the terminals connected in parallel to the line connection terminals 1a and 1b close the loop to use the line, the voltage between the line connection terminals 1a and 1b decreases. here,
When the voltage between the line connection terminals 1a and 1b decreases, the voltage applied to the voltage detection circuit 15 also decreases, so the voltage detection circuit 15 detects this and sends out an output from the output terminal 16.

In addition, when the terminal device releases the line, the line connection terminal 1a,
Since the voltage across lb becomes 48V again, voltage detection circuit 1
The output from 5 is turned off.

Here, the resistance values of the resistors 14a and 14b are sufficiently high resistance (-IMΩ for boat fishing)
or above), and the loop does not close when viewed from the station (the station detects closure when the line current is 20
(from around mA).

Since the terminal operates as described above, by monitoring the output 16 of the line monitoring circuit B shown in FIG. 1, the terminal can know whether the line is in use or not.

Although the embodiment shown in FIG. 1 has been described in the case of one terminal device, when a large number of terminal devices are connected in parallel to one line, the connections are made as shown in FIG. 2. Furthermore, although the circuit shown in FIG. 2 has a line monitoring device B built into each terminal, if one line monitoring circuit B is used, it is connected as shown in FIG.

Furthermore, the rectifier bridge circuit 13 shown in FIG. 1 is connected in order to operate normally even if the voltage polarity applied due to line connection is reversed; if the voltage polarity is constant, This rectifier bridge circuit 13 is unnecessary.

〔Effect of the invention〕

As described above, the present invention monitors the voltage between two lines of a line and detects whether the line is in use or not, so that all terminals connected in parallel can monitor the line at any other terminal at any time. In addition to being able to detect when the device is in use, the loop resistance of the terminal does not increase, and since a large number of terminals need only be connected in parallel to the line, it is possible to easily expand the number of terminals.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a line monitoring circuit used in a multi-line response device of the present invention, FIGS. 2 and 3 are block diagrams showing an example of use of the circuit in FIG. 1, Fig. 4 is a block diagram showing a conventional multi-line response device, Fig. 5 is a circuit diagram showing a conventional line monitoring circuit, and Figs. 6 and 7 are blocks showing usage examples using the circuit in Fig. 5. It is a diagram. la to 1n... line connection terminal, B... line monitoring circuit, 14a, 14b, 14c... resistor, 15... voltage detection circuit, 16... output terminal. Patent applicant: Pioneer Ansahone Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] A voltage detection circuit that detects changes in voltage is connected between two wires of a subscriber telephone line, and when the output from the voltage detection circuit drops below a preset voltage, the loop of the subscriber telephone line is closed. and determining that the loop is open when the value rises above the set value.