JPH10136332A - Security system for using two-way catv transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the maintenance, to avoid a complicated configuration and to reduce a time required for fault discrimination by locating and troubleshooting occurrence of a fault in a 2-way CATV transmission line or a monitor terminal equipment without interrupting guard supervision or fire alarm detection and information collection of intrusion detection utilizing the 2-way CATV transmission line. SOLUTION: A center equipment 20 stores sequentially a reception state of a response signal response to polling control to supervisory terminal equipments 10-1...10-n conducted sequentially by the equipment 20. In the case that the center equipment 20 cannot receive a normal response signal from the supervisory terminal equipment 10-1...10-n, the equipment 20 locates and discriminates occurrence of the fault of each of the supervisory terminal equipments 10-1...10-n or the fault in a 2-way CATV transmission line 28 up to the supervisory terminal equipments 10-1...10-n for polling control based on the stored reception state data from the supervisory terminal equipments 10-1...10-n to which polling control is applied just before or after.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way CATV transmission line, in which a center device performs security monitoring of fire detection and intrusion detection through a monitoring terminal device, and performs two-way CA.
The present invention relates to a two-way CATV transmission line use security system that determines whether an abnormality has occurred in a TV transmission line or a monitoring terminal device.

[0002]

2. Description of the Related Art Conventionally, in a security system using a two-way CATV transmission line, a center device installed in a CATV station is changed to a monitoring terminal device installed in a monitoring destination such as a plurality of security-targeted companies and stores. Sequential, bidirectional CATV
Polling control is performed through a transmission path, and monitoring information is collected from a plurality of security monitoring destination monitoring terminal devices. A fire detection sensor and an intrusion detection sensor are connected to the monitoring terminal device of the security monitoring destination. The center device collects information related to the fire detection and the intrusion detection as a response signal, and monitors the security. I have.

The center device performs fire detection and intrusion detection based on a response signal from a monitoring terminal device received in response to transmission of a polling control signal. In other words, security monitoring is performed at a remote location using a two-way CATV transmission path. Based on the response signal of each security monitoring destination monitoring terminal device, information on fire detection and intrusion detection is displayed on a CRT monitor on a screen and printed out from a printer.

In such a security system using a bidirectional CATV transmission line, when a response error occurs in which a response signal cannot be received, the occurrence of an abnormality in the bidirectional CATV transmission line or the monitoring terminal device is separated and determined, and quick recovery measures are taken. Need to do.

[0005] As an example of such an abnormality determination of a bidirectional CATV transmission line, a "CATV terminal device" disclosed in Japanese Patent Application Laid-Open No. Sho 61-208989 is known. In this conventional example, a check code is superimposed on information exchange data and transmitted from the center device. The receiving terminal device detects a reception error and stores the reception error every time the reception error occurs.

When a receiving error occurs more than a specified number of times, this receiving terminal device is disconnected from the bidirectional CATV transmission line, and the receiving unit of the receiving terminal device takes in the data transmitted from the receiving terminal device to judge the abnormality. ing. An abnormality in the receiving terminal device or the bidirectional CATV transmission line is separated and determined from the presence or absence of the abnormality.

[0007]

However, the above-mentioned conventional CATV system has the following problems (1) and (2).
The problem (3) is considered.

[0008] (1) The receiving terminal device determines whether or not an abnormality has occurred in its own device or the bidirectional CATV transmission path, and determines whether the receiving terminal device does not respond due to abnormal operation on the center device side, or both. It is not possible to determine whether information exchange with the receiving terminal device cannot be performed due to the occurrence of an abnormality in the directional CATV transmission path. Therefore, it takes a long time to determine the abnormality, and the maintainability is poor.

(2) In the conventional example of Japanese Patent Application Laid-Open No. Sho 61-208989, when a receiving error occurs more than a specified number of times, this receiving terminal device is disconnected from the bidirectional CATV transmission line, and transmission data from the receiving terminal device is transmitted. The receiving unit of the own device takes in the data and judges the abnormality. That is, since the abnormality of the receiving terminal device or the bidirectional CATV transmission line is determined based on whether or not an abnormality has occurred, the configuration is complicated.

(3) In the prior art, when a receiving error occurs more than a specified number of times, the receiving terminal device is connected to the bidirectional C.
It is separated from the ATV transmission line, and the receiving unit of its own device takes in the transmission data of the receiving terminal device to determine the abnormality.
Therefore, a large amount of time is required for abnormality determination. That is, the polling control for the next receiving terminal device cannot be performed during the time of this abnormality determination, so that much time is required for the abnormality determination.

The present invention solves the above-mentioned problems in the prior art, and does not interrupt security monitoring by collecting information on fire detection and intrusion detection using a bidirectional CATV transmission line, without interrupting security monitoring. A bidirectional CATV transmission line use security system that can determine the occurrence of an abnormality in a transmission line or a monitoring terminal device separately, makes maintenance easy, and can reduce the time for abnormality determination without complicating the configuration. The purpose is to provide.

[0012]

In order to achieve the above object, according to the present invention, a center device uses a bidirectional CATV transmission line to transmit emergency detection information from a plurality of monitoring terminal devices by polling control. In the two-way CATV transmission line or security system using the two-way CATV transmission line to determine the occurrence of an abnormality in the two-way CATV transmission line or the monitoring terminal device, the center device responds to the polling control signal sequentially transmitted from the plurality of monitoring terminal devices. The reception state of each response signal is stored, and when the response signal cannot be received, the bidirectional CATV transmission path or the monitoring terminal is used based on the reception state of the monitoring terminal device that performed the polling control immediately before or immediately after storing the response signal. The configuration is such that the occurrence of an abnormality in the device is determined separately.

According to a second aspect of the present invention, there is provided a security system using a two-way CATV transmission path, wherein the center apparatus sequentially transmits, via a two-way CATV transmission path, a polling control signal in which individual addresses are superimposed to a plurality of monitoring terminal apparatuses. A signal transmitting unit, a response signal receiving unit for receiving a response signal including emergency detection information from the monitoring terminal device with respect to the transmission polling control signal through the bidirectional CATV transmission path, and polling a reception state of the response signal from the response signal receiving unit. Terminal status storage means for storing for each monitoring terminal device that has performed control; and when a response signal cannot be received, the occurrence of an abnormality in the bidirectional CATV transmission line or the monitoring terminal device is determined based on the reception status of the response signal. Control means for controlling the Scan signal receiving means to display the very detection information received, and bidirectional CAT control means determines
Display means for displaying the occurrence of an abnormality in the V transmission path or the monitoring terminal device.

According to a third aspect of the present invention, in the security system using a two-way CATV transmission line, the monitoring terminal device is connected to a two-way CATV transmission line, receives a polling control signal from a center device, and outputs an emergency detection signal. Transmission / reception means for transmitting the superimposed response signal, storage means for storing the address of the own device, sensor interface processing means for receiving a detection signal from the emergency detection sensor, and storage of a polling control signal addressed to the own device from the transmission / reception means Control means for controlling the transmission of a response signal superimposed with the emergency detection signal from the sensor interface processing means through the transmission / reception means when the identification is made by comparing with the own device address stored in the means, and when they match, .

According to a fourth aspect of the present invention, when the center device cannot receive the response signal, the center device receives the response signal from the monitoring terminal device by the immediately preceding polling control when the center device cannot receive the response signal. If not, it is determined that an abnormality has occurred on the bidirectional CATV transmission path.

According to a fifth aspect of the present invention, in the security system using a two-way CATV transmission line, when the center device cannot receive a response signal from the monitoring terminal device (B) that has performed the polling control, it immediately before storing the response signal. When the response signal from the monitoring terminal device (A) by the polling control is normally received, the next monitoring terminal device (C)
When the response signal from the monitoring terminal device (C) is normally received, the monitoring terminal device (B) that has failed to receive the response signal is determined to be abnormal, and When a response signal from the monitoring terminal device (C) cannot be normally received, it is configured to determine that an abnormality has occurred in the bidirectional CATV transmission line and to determine it.

In the security system using a two-way CATV transmission line, the emergency detection is at least a fire detection and an intrusion detection.

The security system using a two-way CATV transmission path according to claim 7, wherein any one or combination of a screen display unit, a sound notification unit, a synthesized voice notification unit, and a print output unit is provided as the display means. The location of the emergency detection where the device is installed, the bidirectional CATV transmission line where the abnormality has occurred, and the installation location of the monitoring terminal device are displayed by any one or combination of screen display, sound notification, synthesized voice notification, and printout.

In the security system using the bidirectional CATV transmission line having such a configuration, the reception status of each response signal from the plurality of monitoring terminal devices to the polling control signal sequentially transmitted from the center device is stored. When the response signal cannot be received, the occurrence of an abnormality in the bidirectional CATV transmission line or the monitoring terminal device is separated and determined based on the reception state of the monitoring terminal device that has performed the polling control immediately before or immediately after storing the response signal. .

As a result, without interrupting the security monitoring by collecting information on fire detection and intrusion detection using the bidirectional CATV transmission line, a determination is made to determine whether an abnormality has occurred in the bidirectional CATV transmission line or the monitoring terminal device. The maintenance is facilitated, and the time for abnormality determination is reduced without complicating the configuration.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a security system using a two-way CATV transmission line according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a bidirectional CATV of the present invention.
It is a block diagram showing composition in an embodiment of a security system using a transmission line. The two-way CATV transmission line use security system shown in FIG. 1 is installed in a CATV station, performs security monitoring by collecting information on fire detection and intrusion detection in a remote place, and generates an abnormality in the two-way CATV transmission line or the monitoring terminal device. And a center device 20 for performing control for determining by dividing.

Further, the center device 20 and monitoring terminal devices 10-1 to 10-n installed at monitoring destinations of a plurality of companies and stores to be guarded are connected by a bidirectional CATV transmission line 28. Each of the monitoring terminal devices 10-1 to 10-n has a fire detection sensor 10a and an intrusion detection sensor 1
0b is connected, and information of fire detection and intrusion detection here is collected by polling control performed by the center device 20.

The center device 20 includes a monitoring terminal device 10-1.
.. 10-n are sequentially transmitted to the bidirectional CATV transmission line 28 with a polling control signal transmitting section 21 in which individual addresses are superimposed. Further, a response signal in which fire detection and intrusion detection are superimposed from the monitoring terminal devices 10-1 to 10-n that has received the polling control signal transmitted from the polling control signal transmission unit 21 is transmitted to the bidirectional CATV transmission path 28. And a response signal receiving unit 22 that receives the response signal through the network.

Further, the center device 20 includes information collection and monitoring terminal devices 10- for fire detection and intrusion detection.
1. a control unit 23 for performing control to determine whether an abnormality has occurred in the 10-n or bidirectional CATV transmission line 28;
Whether or not the information of fire detection and intrusion detection has been received, that is, the reception state of the response signal receiving unit 22 that is the operation state of the monitoring terminal devices 10-1 to 10-n is stored under the control of the control unit 23, and Terminal status storage unit 24 for reading and outputting
Is provided.

The monitoring terminal 1 is controlled by the control unit 23.
0-1... 10-n are temporarily stored, and
Under the control of the control unit 23, the information of fire detection and intrusion detection from the monitoring terminal devices 10-1... 10-n is displayed on the screen, and the monitoring terminal devices 10-1. 10-n or bidirectional CATV transmission line 28
And a display unit 26 for displaying on the screen information that is determined by separating the occurrence of an abnormality.

FIG. 2 is a block diagram showing the configuration of the monitoring terminal devices 10-1 to 10-n. The example of FIG.
A response signal that is connected to the TV transmission line 28, receives a polling control signal with an address superimposed from the center device 20, and superimposes information on fire detection and intrusion detection when the address matches the address of its own device stored in advance. Is transmitted and received. Further, the controller 31 identifies a polling control signal addressed to the own device based on the own device address, and controls transmission of a response signal in which information of fire detection and intrusion detection is superimposed, and stores the address of the own device. A memory 32 and a sensor interface (I / F) unit 33 for receiving detection signals of the fire detection sensor 10a and the intrusion detection sensor 10b shown in FIG. 1 are provided.

Next, the operation of this embodiment will be described. In FIG. 1, the control unit 23 of the center device 20 sends a polling control signal transmitting unit 21 to the monitoring terminal device 1.
10-n are sequentially transmitted to the bidirectional CATV transmission line 28 with a polling control signal in which the individual addresses of the monitoring terminal devices 10-1... Further, the control unit 23 captures, via the response signal receiving unit 22, a response signal from the monitoring terminal devices 10-1 to 10-n for the polling control signal transmitted by the polling control signal transmitting unit 21.

Further, the control unit 23 fetches fire detection and intrusion detection information superimposed on the response signal, and in a normal reception state where the fire detection and intrusion detection information is obtained, that is, the monitoring terminal of this address. Apparatus 10-1 ...
When 10-n is operating normally, the control unit 23 detects a fire from the monitoring terminal device 10-1.
Control is performed to display information indicating a normal operation of intrusion detection on the screen of the display unit 26.

Here, when the control unit 23 has successfully received the fire detection and intrusion detection information, the terminal state storage unit 24
10-n from the monitoring terminal devices 10-1... 10-n at the same address in the previous polling control (hereinafter referred to as reception state data). In the case of abnormal reception in which there is no information of fire detection and intrusion detection in the read previous reception state data, the reception state data by polling control for the monitoring terminals 10-1 to 10-n of the same address this time is normal, For example, by performing a recovery operation, this monitoring terminal device 10-1.
The control unit 23 performs control to store information indicating that 0-n has returned to the normal operation in the terminal state storage unit 24.

If the control unit 23 cannot receive a response signal even after a certain period of time, the control unit 23 monitors the addresses of the addresses stored in the terminal state storage unit 24 that performed the polling control immediately before. 10-n reception status data is read from the terminal status storage unit 24. In the case of a reception error in which information of fire detection and intrusion detection is not included in the reception state data, it is determined that an error has occurred in the bidirectional CATV transmission line 28. The occurrence of an abnormality in the bidirectional CATV transmission path 28 is displayed on the screen of the display unit 26 under the control of the control unit 23. Further, the control unit 23 performs control for storing the occurrence of an abnormality in the bidirectional CATV transmission line 28 in the terminal state storage unit 24.

Further, if the response signal cannot be received even after the elapse of a certain time, the monitoring terminal devices 10-1... 10-n of the address corresponding to the immediately preceding polling control stored in the terminal status storage unit 24 receive. The status data is read out, and if the reception status data is normal, that is, if it has information on fire detection and intrusion detection, the terminal status storage unit 24 cannot receive the response signal even after a certain period of time. The addresses of the monitoring terminal devices 10-1 to 10-n are stored.

Further, under the control of the control unit 23, polling control is performed on the monitoring terminal devices 10-1 to 10-n of the next addresses. The response signal is received by the response signal receiving unit 22 from the monitoring terminal devices 10-1 to 10-n of the addresses that have performed the polling control, and in the case of normal reception in which information of fire detection and intrusion detection is obtained, Since the response signal cannot be received even after a certain period of time has elapsed, it is determined that the monitoring terminal devices 10-1 to 10-n at the stored addresses have abnormal operations.

If the response signal receiving section 22 does not normally receive the response signal in the next polling control, it is determined that an abnormality has occurred in the bidirectional CATV transmission path 28. Then, the control unit 23 stores the occurrence of an abnormality in the monitoring terminal devices 10-1 to 10-n or the occurrence of an abnormality in the bidirectional CATV transmission line 28 in the terminal state storage unit 24,
At the same time, control for displaying a screen on the display unit 26 is performed.

As described above, the monitoring terminal devices 10-1.
-N, the reception state data indicating whether or not the information of the fire detection and the intrusion detection with respect to the polling control signal is received is sequentially stored, and when a normal response signal cannot be received from the monitoring terminal devices 10-1 to 10-n, 10-n based on the reception status data from the monitoring terminal devices 10-1... 10-n that performed the polling control immediately before or immediately after.
The occurrence of an abnormality for each of 0-n or the occurrence of an abnormality in the bidirectional CATV transmission line 28 is determined separately.

Next, the monitoring terminal devices 10-1... 10-n and the center device 2 for separating and determining the occurrence of this abnormality are described.
The operation of 0 will be described individually.

FIG. 3 is a flowchart showing a processing procedure of the operation of the monitoring terminal devices 10-1 to 10-n. In FIG. 3, in the monitoring terminal devices 10-1 to 10-n, the control unit 3
1 determines whether the polling control signal from the center device 20 has been received through the transmission / reception unit 30 (step S10). If received (step S10: Ye
s) The control unit 31 reads the address unique to the own device from the memory 32 and compares it with the address in the polling control signal to determine whether the polling control signal is addressed to the own device (step S11).

If it is determined in step S11 that the address is the address of the own device (Yes), the control unit 31 sends the fire detection signal to the center device 20 via the sensor I / F unit 33 from the fire detection sensor 10a and the intrusion detection sensor 10b. The response signal on which the detection signal is superimposed is transmitted to the center device 20 through the transmission / reception unit 30 and the bidirectional CATV transmission line 28 (step S12). The address of the own device may be superimposed and transmitted together with the fire detection signal and the intrusion detection signal.

FIG. 4 is a flowchart showing the processing procedure of the operation of the center device 20. In FIG. 4, the center device 20 sequentially polls the monitoring terminal devices 10-1... 10-n by superimposing individual addresses of the monitoring terminal devices 10-1. The control signal is transmitted to the bidirectional CATV transmission line 28 (step S21).

Next, the center device 20 determines whether or not a response signal has been received from the monitoring terminal devices 10-1 to 10-n of this address within a predetermined time (step S22). If it can be received (Yes), it is determined whether or not the addresses of the monitoring terminal devices 10-1 to 10-n that performed the polling control are stored (step S23). Then, the stored previous polling control is performed. It is determined whether or not the response signal of the address for which has been performed has been normally received (step S24).

Next, in step S24, if the reception status data of the address subjected to the previous polling control is normal (Yes), fire detection and intrusion are performed on the response signal received at the address subjected to the current polling control. It is determined whether or not the detection information is superimposed. If the reception status data of the address subjected to this polling control is normal, the fact that the reception status data is normal is stored (steps S25 and S26). ). Next, in order to perform polling control on the next monitoring terminal devices 10-1 to 10-n,
The address in the polling control signal is updated, and the process returns to step S21 (step S27).

If the response signal is not received within a predetermined time in step S22 (No), the monitoring terminal device 10-1 ... 1 of the address where the polling control was performed immediately before is received.
The reception status data from 0-n is read, and whether the reception status data is normal or abnormal is determined. If the reception status data is normal, the address at which the response signal could not be received is temporarily stored (step S28, S29).

If it is determined in step S23 whether a response signal has been received within a predetermined time or not, and there is an address that is temporarily stored (Yes), the address of the address for which the response signal could not be received is determined. 10-n are displayed on the screen, and then the temporarily stored addresses are deleted (step S3).
0, S31). If the reception status data of the address in the previous polling control is abnormal in step S24 (No),
According to the determination in step S22, the reception status of the address in the current polling control is normal, and a display is made on the screen that the monitoring terminal devices 10-1 to 10-n at this address have returned to the normal operation (step S32).

Further, if fire detection and intrusion detection information is superimposed on the response signal received in step S25 (Yes), the reception of an abnormal signal indicating that fire or intrusion has been detected is displayed on the screen (step S33). ). Also,
When the reception status data of the address for which the polling control was performed immediately before is read in step S28, if this is abnormal (No), it is determined whether or not there is an address stored before (step S34), and the address is stored here. (Yes), the monitoring terminal device 10-1 at this address ...
An abnormal image has occurred on the bidirectional CATV transmission line 28 up to 10-n, and this abnormal state is displayed on the screen (step S3).
5).

Next, the occurrence of an abnormality in the bidirectional CATV transmission line 28 up to the address where the response signal is not transmitted is displayed on the screen (step S36). Step S34
If there is no address stored in step (No), step S3
6 is processed. Next, the monitoring terminal devices 10-1 ... 10 that could not receive the temporarily stored response signal
The address of -n is deleted, the abnormality occurrence in the monitoring terminal devices 10-1 ... 10-n that could not receive this response signal is stored, and the process proceeds to step S37.

As described above, the polling control is performed immediately before or immediately after the response signal cannot be received without stopping the polling control, that is, without interrupting the security monitoring by collecting information on fire detection and intrusion detection. 10-n based on the reception status data from the monitoring terminal devices 10-1... 10-n, and an abnormality occurrence in the bidirectional CATV transmission line 28 is determined. ing.

In the display section 26 of the center device 20,
The information of fire detection and intrusion detection is displayed on the screen, and the occurrence of an abnormality in the monitoring terminal device 10-1 ... 10-n or the occurrence of an abnormality in the bidirectional CATV transmission line 28 is displayed on the screen. In this case, the emergency detection location where the monitoring terminal devices 10-1 to 10-n are installed, the bidirectional CATV transmission line 28 where the abnormality has occurred, and the installation locations of the monitoring terminal devices 10-1 to 10-n are displayed on the screen.

In addition to this screen display, a sound notification unit, a synthesized voice notification unit, and a print output unit for performing any one or a combination of sound notification, synthesized voice notification, and print output may be provided.

[0048]

As is apparent from the above description, according to the two-way CATV transmission line use security system of the present invention, a plurality of monitoring terminal devices respond to a polling control signal which is sequentially performed. The reception state of each response signal is stored. If the response signal cannot be received based on the reception state of the monitoring terminal device that has performed the polling control immediately before or immediately after the storage, the bidirectional CATV transmission path or monitoring is performed. The occurrence of an abnormality in the terminal device is determined separately.

Thus, it is possible to determine whether an abnormality has occurred in the bidirectional CATV transmission line or the monitoring terminal device without interrupting security monitoring by collecting information on fire detection and intrusion detection using the bidirectional CATV transmission line. Become. As a result, the maintenance becomes easy, and the time for the abnormality determination can be reduced without complicating the configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a security system using a bidirectional CATV transmission line according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a monitoring terminal device in FIG.

FIG. 3 is a flowchart illustrating a processing procedure of an operation of the monitoring terminal device in the embodiment.

FIG. 4 is a flowchart showing a processing procedure of an operation of the center device in the embodiment.

[Explanation of symbols]

 10-1 ... 10-n Monitoring terminal device 10a Fire detection sensor 10b Intrusion detection sensor 20 Center device 21 Polling control signal transmission unit 22 Response signal reception unit 23 Control unit 24 Terminal status storage unit 25 Address temporary storage unit 26 Display unit 28 Both Directed CATV transmission line 30 Transmitter / receiver 31 Controller 32 Memory 33 Sensor I / F

Claims (7)

[Claims] 1. A center device collects emergency detection information from a plurality of monitoring terminal devices by polling control using a bidirectional CATV transmission line, and separates occurrence of abnormality in the bidirectional CATV transmission line or the monitoring terminal device. In the security system using a two-way CATV transmission path to be determined, the center device stores reception states of respective response signals from a plurality of monitoring terminal devices with respect to a sequentially transmitted polling control signal, and when a response signal cannot be received, Bidirectional CATV transmission, characterized in that an abnormality occurrence in the bidirectional CATV transmission path or the monitoring terminal device is separated and determined based on the reception state of the monitoring terminal device that has performed the polling control immediately before or immediately after the storage. Road use security system. 2. A polling control signal transmitting means for sequentially transmitting a polling control signal superimposed with an individual address to a plurality of monitoring terminal devices through a bidirectional CATV transmission line as the center device, and a monitoring terminal device for a transmission polling control signal. Signal receiving means for receiving a response signal including emergency detection information from the PC through a two-way CATV transmission path, and receiving status of the response signal from the response signal receiving means for each monitoring terminal device that has performed polling control. Terminal state storage means, and control means for performing control to determine the occurrence of an abnormality in the bidirectional CATV transmission path or the monitoring terminal device based on the reception state of the response signal when the response signal cannot be received, Displays the emergency detection information received by the response signal receiving means, One, two-way CAT of claim 1, wherein the control means further comprising a display means for displaying the abnormality of bidirectional CATV transmission path or monitoring terminal device determines
Security system using V transmission path. 3. A transmission / reception means connected to a bidirectional CATV transmission line, receiving a polling control signal from a center device, and transmitting a response signal superimposed with an emergency detection signal, as the monitoring terminal device; Storage means for storing the address of the device, sensor interface processing means for receiving a detection signal from the emergency detection sensor, and a polling control signal addressed to the own device from the transmitting / receiving means being compared with the own device address stored in the storage means. And control means for controlling transmission of a response signal on which an emergency detection signal is superimposed from the sensor interface processing means through the transmission / reception means when the addresses coincide with each other. Bidirectional CAT
Security system using V transmission path. 4. When the center device cannot receive a response signal, and the response signal from the monitoring terminal device is not received by the polling control immediately before storing, an abnormality in the bidirectional CATV transmission path. 2. The security system using a two-way CATV transmission line according to claim 1, wherein it is determined that an occurrence has occurred. 5. When the center device cannot receive a response signal from the monitoring terminal device (B) that has performed the polling control, the center device stores the response signal from the monitoring terminal device (A) by the immediately preceding polling control. Is normally received, polling control is performed to the next monitoring terminal device (C), and when a response signal from this monitoring terminal device (C) is normally received, the response signal can be received. If it is determined that the monitoring terminal device (B) that did not have an error and that the response signal from the monitoring terminal device (C) could not be normally received, it is determined that an abnormality has occurred in the bidirectional CATV transmission path. 2. The two-way CATV transmission line use security system according to claim 1, wherein the determination is performed by dividing. 6. The two-way CATV transmission line use security system according to claim 1, wherein said emergency detection is at least fire detection and intrusion detection. 7. The display means includes any one or a combination of a screen display unit, a sound notification unit, a synthesized voice notification unit, and a print output unit. The two-way CATV transmission line use security according to claim 2, wherein the installation location of the CATV transmission line and the monitoring terminal device is displayed by any one or combination of screen display, sound notification, synthesized voice notification, and printout. system.