JPH03186052A - Line disconnection detecting device - Google Patents

Abstract

PURPOSE:To send a disconnection warning signal to a monitor center when a telephone line is broken by sending the disconnection warning signal to the monitor center through one of two branch telephone lines which is normal if one telephone line is broken. CONSTITUTION:Input terminals 7 and 8 are provided for the two telephone lines La and Lb obtained by branching the same subscriber telephone line and if an abnormality detection sensor 13 detects an abnormal state, a warning transmitter 16 informs the monitor center of the generation of the abnormal state immediately through the telephone line La, etc. If the telephone line La enters a short-circuit state, a disconnection detection part 1 detects that, a line switching part 3 outputs the disconnection warning signal and a switching signal, and a switching relay 4 operates to connect a terminal 9 to the input terminal 8. The warning transmitter 16 on receiving the disconnection warning signal dials the monitor center automatically and sends the disconnection warning signal to the monitor center through the telephone line Lb. Consequently, if one of the telephone lines La and Lb is disconnected, the disconnection warning signal is sent to the monitor center.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a mechanical security system using a telephone line,
In particular, the present invention relates to a line disconnection detection device that detects a disconnection failure in a telephone subscriber's telephone line and transmits the detected disconnection to a monitoring center of a mechanical security system.

[Conventional technology]

Generally, mechanical security systems using telephone lines include a sensor that detects abnormal situations in the security target, and an alarm transmission device that receives the detection signal emitted by the sensor, processes the detection signal, and transmits it to a remote monitoring center. , a telephone line used to transmit the alarm signal issued by this alarm transmission device to the monitoring center, and a receiving device at the monitoring center that receives this alarm signal.

[Problem to be solved by the invention]

However, in the mechanical security system described above,
If the telephone line was disconnected for some reason, an alarm signal would not be sent to the monitoring center, and the system would no longer function, making it impossible for the monitoring center to detect the occurrence of an abnormal situation to be guarded.

Therefore, disconnection detection devices for telephone lines have been developed. For example, when a telephone line is disconnected, it is detected and a buzzer or siren is sounded or other telephone lines are notified (Japanese Patent Laid-Open No. 58-213554). Public notice) was considered. However, even if a buzzer or siren sounds, the monitoring center cannot be notified, and in order to notify other subscribers, it is necessary to install lines and equipment, which is costly. was there. In addition, lines may be disconnected due to maintenance or connection changes on the carrier's side, and it is not possible to distinguish between disconnections due to maintenance and disconnections due to abnormal situations, resulting in frequent false alarms. There was a possibility.

This invention was developed to solve the above-mentioned HH problem, and is capable of not only reporting disconnection alarm No. 18 to the monitoring center when a telephone line is disconnected, but also being able to be constructed at low cost and preventing false alarms. An object of the present invention is to obtain a line disconnection detection device that can prevent line disconnection.

(Means for Solving the Problem) The line disconnection detection device according to the invention of claim 1 includes each disconnection detection unit that detects each IFT line of a telephone line branched into two, and a disconnection detection unit that detects disconnection from each disconnection detection unit. It is equipped with a line switching unit that receives detection signals and is switchably connected to each telephone line, and when one telephone line is disconnected, it is connected to the other telephone line and outputs a disconnection alarm signal to the monitoring center. be.

Further, in the line disconnection detection device according to the second aspect of the invention, the line switching section outputs an alarm signal after a predetermined period of time when the telephone lines are simultaneously disconnected.

[Function] In the invention of claim 1, when one of the two branched telephone lines is disconnected, a disconnection alarm signal is sent to the monitoring center via the other telephone line.

According to the second aspect of the present invention, in addition to the above-mentioned effects, an alarm signal is output after a predetermined time when the telephone lines are simultaneously disconnected.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows the configuration of the line disconnection detection device 12 according to this embodiment, and 1.2 is a disconnection detection section for detecting disconnection of the telephone line, for example, detects the voltage of the telephone line to check for disconnection. 3 is a line switching unit that receives a disconnection signal from the disconnection detection unit 1.2 and outputs a switching signal and a disconnection alarm signal; 4 is a line switching unit that receives a switching signal from the line switching unit 3 and operates a contact 4a to switch the line. A switching relay 5 is an alarm output relay that receives a disconnection alarm signal from the line switching unit 3 and outputs it to the alarm transmission device 16 by activating a contact 5a.
7.8 is the input terminal of two telephone ports fkllL-, L& created by branching the T-talk line of the same subscription, and 9 is the connection line 14
10 is a terminal for connecting the alarm transmission device 16 via the connection line 15, 10 is a terminal for connecting the disconnection alarm output from the alarm output relay 5 to the alarm transmission device 16 via the connection line 15, 6 is a telephone line,
L.

A local alarm output relay 11 operates in response to a signal from the line switching unit 3 when both of the lines are disconnected.
, Lb are both disconnected, this is a terminal that outputs an alarm signal.

FIG. 2 shows the configuration of a mechanical security system having the above-mentioned line disconnection detection device 12, 13 is provided in the security area,
An anomaly detection sensor 16 that detects the abnormal situation is an alarm transmission device that receives an anomaly detection signal from the anomaly detection sensor 13 and transmits an alarm signal to a monitoring center (not shown) through a telephone line. Transmission device 1
6.

Next, the operation of the above configuration will be explained.0 line disconnection detection device 1
2, a telephone port IL is normally connected from an input terminal 7 to a terminal 9 via a contact 4a of a switching relay 4. Here, if an abnormal state such as an intrusion or a fire occurs, the abnormality detection sensor 1
3, the detection signal is transmitted to the alarm transmission device 16.
, the alarm transmission device 16 immediately automatically dials the predetermined telephone number of the monitoring center and connects the connection line 1.
4. Notify the monitoring center of the occurrence of an abnormal condition via the terminal 9, the contact 4a, the input terminal 7, and the telephone line.

Also, when the telephone line becomes disconnected, the disconnection detection section 1 detects this, the line switching section 3 receives the disconnection signal and outputs a disconnection alarm signal, and the alarm output relay 5 is activated to close its contact 5a. is turned off, and the terminal 10 becomes open. As a result, a disconnection alarm signal is transmitted from the terminal 10 to the alarm transmission device 16 via the connection line 15. At the same time, the line switching unit 3 determines that the telephone line L is normal and outputs a switching signal. Upon receiving this, the switching relay 4 is activated and its contact 4a is switched, and the terminal 9 is connected to the input terminal 8. connected to. When the alarm transmission device 16 receives the disconnection alarm signal, it automatically dials the monitoring center and reports the disconnection alarm signal to the monitoring center via the connection line 14, the terminal 9, the contact 4a, the input terminal 8, and the telephone line Lb.

In addition, when the telephone line becomes disconnected, the disconnection detection section 2 detects this and sends a disconnection signal to the line switching section 3, and the line switching section 3 activates the alarm output relay 5 to The contact 5a is turned off and the terminal 10 is opened. Thereby, the line switching unit 3, which sends the disconnection alarm signal from the terminal 10 to the alarm transmission device 16 via the connection line 15, becomes the disconnection detection unit l.

From the output of 2, it is determined that the line is normal and the line is disconnected, and if terminal 9 is connected to input terminal 7, it is left as is, and if terminal 9 is connected to input terminal 8, it is determined that it is disconnected. The switching relay 4 is activated to switch its contact 4a. Therefore, the alarm transmission device 16 automatically dials the monitoring center and sends a disconnection alarm signal to the monitoring center via the connecting line 14, the terminal 9, the contact 4a, the input terminal 7, and the telephone line 1-.

Next, if both telephone lines L- and Lb are disconnected,
The disconnection detectors 1 and 2 both detect a disconnection, and the line switching unit 3 determines that this disconnection is due to maintenance or inspection by the telecommunications carrier that provides the telephone line, and the disconnection continues for a predetermined period of time, e.g. If it continues for more than 15 minutes, the local alarm output relay 6 is activated, its contact 6a is activated, a sound device such as a hell or siren connected to the terminal 11, or a display device such as a revolving light is activated, and the telephone is activated. It is reported that both lines L and L are disconnected. However, it is not possible to report to the monitoring center using a telephone line.
If even one of them returns to normal, no alarm signal is output from the terminal 11.

[Effects of the Invention] As described above, according to the present invention, a telephone line is branched into two lines, and if one of them is disconnected, it is determined that the disconnection is intentional and the line is connected to the monitoring center via the other telephone line. A disconnection alarm signal can be transmitted, improving the security level and the reliability of the system. Furthermore, there is no need to use another subscriber's telephone line, and it is sufficient to simply detect a disconnection and switch to another branched line, resulting in an inexpensive configuration. Furthermore, maintenance, inspection, etc. by telecommunications carriers are carried out at the exchange center or a location close to it, so both of the two branched telephone lines are disconnected, and in such cases, reporting to the monitoring center is not possible. Therefore, it can be easily distinguished from an intentional disconnection, and false alarms can be prevented. In addition, if both telephone lines are disconnected, an alarm signal will be issued after a certain period of time, so the security system will not be left in an inactive state without noticing the disconnection, which is also advantageous in terms of security. It is.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a line disconnection detection device according to the present invention, and FIG. 2 is a block diagram of a security system according to the present invention. 1.2...Disconnection detection unit, 3...Line switching unit, 4...
・Switching relay 5...Alarm output relay 6...Local alarm output relay 12...Line disconnection detection device, L
lLl...Telephone line.

Claims (2)

[Claims] (1) Each disconnection detection unit detects disconnection of a telephone line that is branched into two, and each disconnection detection unit receives a disconnection detection signal from each disconnection detection unit and is connected to each telephone line in a switchable manner, so that one telephone line A line disconnection detection device comprising a line switching unit that connects to the other telephone line and outputs a disconnection alarm signal to a monitoring center in the event of a disconnection. (2) The line disconnection detection device according to claim 1, wherein the line switching unit outputs an alarm signal after a predetermined time has elapsed if each telephone line is disconnected at the same time.