JPH03113944A - Subscriber line monitor system - Google Patents

Abstract

PURPOSE:To prevent increase in invalid call processing in a telephone exchange system by allowing a repeater at an exchange side to monitor the transmission state of a monitor signal to a repeater of a subscriber's equipment and the reception state of a monitor signal and a connection signal from the repeater of the subscriber's equipment. CONSTITUTION:A repeater 2 of a subscriber's equipment detects a monitor signal by a monitor signal detector 27 and commands the transmission of a connection signal to a connection signal transmitter 28. When a subscriber is not connected to a repeater 4 of an exchange or the subscriber line is broken and the power supply of the repeater 4 of the exchange is applied, since both an outgoing subscriber line 3AB and an incoming subscriber line 3DE do not exist, while a monitor signal to the outgoing subscriber line 3AB is sent by a control circuit 45, because a connection signal and a monitor signal from the incoming subscriber line 3DE are not detected respectively by a monitor signal detector 47 and a connection signal detector 48, it is discriminated that the line is broken and no scanning signal is sent to an exchange.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a subscriber line monitoring system for extended subscriber lines of a telephone switching system.

[Conventional technology]

Conventionally, two-wire systems have been used as subscriber lines in telephone exchange systems, but their distances have been limited to several kilometers. In order to extend this limit distance, a method is used in which transport devices such as relay devices are provided on the exchange side and the customer equipment side, respectively, to extend the subscriber line. As a method for monitoring this extended subscriber line, a no-call signaling system is used. In other words, when there is no call, the relay device on the exchange side and the relay device on the home device side mutually transmit a signal at a specific frequency within the voice band of 300Hz to 3400Hz, for example, 2600Hz, as a monitoring signal, and when a call is made or when a call is received. , this monitoring signal is stopped, and the presence or absence of the monitoring signal sent from the partner device is determined to detect a change in the state of the partner device.

[Problem to be solved by the invention]

In the conventional subscriber line monitoring system described above, when the monitoring signal that is flowing when there is no call stops, the relay device on the exchange side considers that the in-home device has made a call.

By the way, for convenience of equipment, the exchange side relay device is installed not for each subscriber line but for every several lines. Therefore,
There may be an exchange-side relay device to which a subscriber line is not connected. In this way, if the subscriber lines are not connected from the beginning, the exchange side relay equipment will always remain in the state of detecting calls from the in-house equipment, and if there are many unconnected subscriber lines, the exchange side relay equipment will When the power is turned on, all calls are detected all at once, and the processing in the telephone exchange system increases, causing congestion. Further, even if the installed subscriber line is disconnected, the in-home equipment similarly enters the call detection state, which has the drawback of increasing invalidation processing in the telephone exchange system.

An object of the present invention is to increase invalid call processing in a telephone exchange system by preventing false detection of a call originating state from an in-home device even when a subscriber line is not connected to a relay device on the exchange side or is disconnected. An object of the present invention is to provide a subscriber line monitoring system that can prevent such problems.

[Means to solve the problem]

The subscriber line monitoring system of the present invention includes an in-home equipment side relay device connected to one side of the extended subscriber line, and an exchange side relay device connected to the other side of the subscriber line. In the subscriber line monitoring system that monitors the subscriber line: When there is no call,
a first transmitting a first monitoring signal to the exchange side relay device;
a first supervisory signal detection means for detecting a second supervisory signal sent from the exchange i-side relay device; and when the second supervisory signal is detected, the exchange i-side relay device a connection signal transmitting means for transmitting a connection signal to the subscriber, and stopping the first monitoring signal when the subscriber makes a call; a second relay device for transmitting the second monitoring signal; an exchange-side relay device for monitoring connections, comprising a monitoring signal sending means, a second monitoring signal detecting means for detecting the first monitoring signal, and a connection signal detecting means for detecting the connection signal. It is configured as follows.

〔Example〕

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

Referring to FIG. 1 showing one embodiment of the present invention, a telephone 1
The in-home equipment side relay device 2 connected to the exchange and the exchange side relay device 4 connected to the exchange (not shown) through the digital interface 5 with the exchange connect the down subscriber line 3AB and the up subscriber line 3DE. connected via. The in-home device side relay device 2 includes a communication current supply circuit 21 that supplies communication current to the telephone 1 and a communication current supply circuit 2 connected to the communication current supply circuit 21.
line-4 line conversion circuit 22, a supervisory signal transmitter 26 that transmits a 2600Hz supervisory signal, and a 2600Hz supervisory signal from the partner device.
A supervisory signal detector 27 for detecting a Hz supervisory signal, and 30
a connection signal transmitter 28 that transmits a 00Hz connection signal;
It includes a supervisory signal blocking filter 24 that prevents supervisory signals from entering the 2-wire to 4-wire conversion circuit 22, level adjustment amplifiers 25A and 25B inserted into the speech line, and a control section 23. The exchange side relay device 4 is a level adjustment amplifier 4.
1A, 41B, and 2600) A supervisory signal transmitter 46 that transmits a 1z supervisory signal, a supervisory signal detector 47 that detects a 2600Hz supervisory signal from the partner device, and a 3000H
a connection signal detector 48 that receives the connection signal of z, and an A/D
A conversion circuit 43, a highway interface circuit 44 that interfaces with the highway of the exchange, a supervisory signal and connection signal blocking filter 42 that prevents supervisory signals and connection signals from entering the A/D conversion circuit 43, and a control unit 45. Equipped with.

FIG. 2 is a sequence chart for explaining the operation of one embodiment of the present invention. The operation will be explained below using FIGS. 1 and 2. When the in-home equipment side relay device is connected to the subscriber line and the switch side relay device is powered on, the upstream subscriber line 3DE is connected to the supervisory signal transmitter 26 - level adjustment amplifier 25B - subscriber line 3DE - The downstream subscriber line 3AB is connected via the level adjustment amplifier 41A to the supervisory signal detector 47 to the supervisory signal transmitter 46 to the level adjustment amplifier 4.
1B = subscriber line 3AB - level adjustment amplifier 25A - monitoring signal flows through the monitoring signal detector 27, respectively, and the in-home device side relay device 2. Each exchange side relay device 4 detects a monitoring signal from the other party. In the home device side relay device 2, the supervisory signal detector 27 detects the supervisory signal and instructs the connection signal transmitter 28 to transmit the connection signal. In this normal state of no calls, a supervisory signal is flowing through the downlink subscriber line 3AB, and a supervisory signal signal and a connection signal are flowing through the upstream subscriber line 3DE. In this state, when a call is made from the telephone 1, the control circuit 23 is activated by the supervisory signal transmitter 2 based on the call detection information from the call current supply circuit 21, as shown in FIG.
The sending of the monitoring signal No. 6 is stopped. As a result, when the supervisory signal detector 47 sends the supervisory signal disconnection information to the control circuit 45, the control circuit 45 checks it together with the connection signal detection information, and determines that there is a connection signal and no supervisory signal, indicating that the call is in a calling state. It is determined that there is a scanning signal indicating , and a notification is sent to the exchange via the highway interface circuit 44. Therefore, since the exchange sends a dial tone to the telephone 1, when the subscriber dials from the telephone 1 and receives a response signal from the exchange, the control circuit 45 stops sending the supervisory signal from the supervisory signal transmitter 46. do. As a result, the supervisory signal detector 27 detects the disconnection of the supervisory signal and instructs the connection signal detector 28 to stop transmitting the connection signal. Then, when the call ends, the original state returns to the normal state as shown in FIG.

When the subscriber line is not connected to the exchange side relay device 4 or when the subscriber line is disconnected, when the power of the exchange side relay device 4 is turned on, the down subscriber line 3AB and the up subscriber line 3DE are connected. Due to the absence of both, although the control circuit 45 is sending the monitoring signal to the downlink subscriber line 3AB, the connection signal and the monitoring signal from the uplink subscriber line 3DE are sent to the monitoring signal detector 47 and the connection signal. Since they are not detected by the detector 48, it is determined that the line is disconnected, and no scanning signal is sent to the exchange.

〔Effect of the invention〕

As explained above, the present invention enables the switchboard side relay device to monitor the transmission status of the monitoring signal to the home device side relay device and the receiving state of the monitoring signal and connection signal from the home device side relay device, thereby making it possible to Even if the telephone line is not connected to the relay device on the exchange side or is disconnected, it is possible to prevent an increase in invalid call processing in the telephone exchange system without falsely detecting that the call is originating from the in-house device. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a sequence chart for explaining the operation of the embodiment of the present invention. 1...Telephone, 2...In-home equipment side relay device, 3AB, 3DE...Subscriber line, 4...
. . . Exchange side relay device, 5 . . . Digital interface with exchange, 21 . . . Call current supply circuit, 22 .
45...Control circuit, 24--Monitoring signal blocking filter, 25A, 25B, 41A, 41B...
・Level adjustment amplifier, 26.46...Monitoring signal transmitter, 27.47...Monitoring signal detector, 2
8...Connection signal transmitter, 42...Monitoring signal and connection signal blocking filter, 43...A/D
Conversion circuit, 44... Highway interface circuit, 48... Connection signal detector.

Claims (1)

[Claims] A subscriber line monitoring system that monitors a subscriber line by having an in-home equipment side relay device connected to one side of the extended subscriber line and an exchange side relay device connected to the other side of the subscriber line. In; a first monitoring signal sending means for sending a first monitoring signal to the exchange side relay device when there is no call; and a first monitor for detecting a second monitor signal sent from the exchange side relay device. signal detection means; and connection signal sending means for sending a connection signal to the exchange side relay device when the second supervisory signal is detected, and when the subscriber makes a call, the first supervisory signal is transmitted. a home device-side relay device for stopping the connection signal; a second supervisory signal sending means for transmitting the second supervisory signal; a second supervisory signal detecting means for detecting the first supervisory signal; 1. A subscriber line monitoring system comprising: connection signal detection means for detecting a connection signal; and an exchange-side relay device for monitoring connections.