JPH0484399A - Terminal device for catv supervisory system - Google Patents

Abstract

PURPOSE:To realize the terminal device of a CATV supervisory system having a simple configuration by providing a poling detecting means, answer signal generating means, and answer signal sending means. CONSTITUTION:The above CATV supervisory system is provided with a poling means which detects a poling signal sent from a center station by receiving the signal from a CATV network 10 and outputs a prescribed signal, answer signal generating means 20 and 22 which generate prescribed answer signals, and answer signal sending means 60, 70, and 80 which send the answer signal from the generating means 20 and 22 to the center station through the CATV network 10 when the poling detecting means outputs the prescribed signal and a contact signal (e) is inputted from equipment to be monitored. Therefore, the terminal device of a CATV supervisory system does not use any CPU and has a simple configuration can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a terminal device for a monitoring system using a CATV network.

[Prior Art] Conventionally, terminal devices of this type of monitoring system have two-way CA
Each terminal device is connected to the center station via TVy4, and in response to polling from the center station, each terminal device sends a response signal indicating the presence or absence of a contact signal from the monitored equipment connected to each terminal device to the center station via the CATV network. Was. Each terminal device is equipped with a CPU, which detects the presence or absence of a contact signal and sends out a response signal.

[Problem to be solved by the invention]

As described above, since the terminal devices of the conventional monitoring system were equipped with a CPU to perform the necessary functions, they had the disadvantage of having a complicated configuration.

An object of the present invention is to eliminate such drawbacks and provide a terminal device for a CATV monitoring system that does not use a CPU and therefore has a simple configuration.

[Means to solve the problem]

The present invention provides a terminal device for a monitoring system using a CATV network, comprising: polling detection means for receiving and detecting a polling signal sent by a center station from the CATV network, and outputting a predetermined signal; and a predetermined response signal. and the polling detection means output the predetermined signal, and when a contact signal is input from the monitored device, the response signal from the response signal generation means is transmitted to the polling device through the connected CATV network. The present invention is characterized by comprising a response signal transmitting means for transmitting a response signal to a center station.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of a terminal device of a CATV monitoring system according to the present invention. Directional coupler 80
connects the CATV transmission line 10 and this terminal device, and transmits the signal from the center station to the CATV transmission line 10. It receives and receives signals from the terminal equipment, and outputs signals from the terminal equipment to the center station through the transmission line 10. The terminal address switch 20 is used to manually set an address unique to this terminal device, and outputs a transmitter control signal a according to the setting. The transmitting section 22 generates a signal of a predetermined frequency based on the transmitting section control signal a from the terminal address switch 20, and outputs it as a transmitting signal. The modulator 30 modulates the signal from the directional coupler 80 using the transmission signal from the transmitter 22, and outputs a modulated signal C. The bandpass filter 40 is the modulator 30
It receives and receives signals from and outputs signals within the passband.

The rectifier 50 rectifies the signal from the bandpass filter 40 and outputs a rectified signal d. The gate receives the contact signal e from the monitored device, and allows the contact signal e to pass when the rectified signal d is input. When the contact signal e is input through the gate 60, the switch 70 becomes conductive and outputs the transmitted signal from the transmitter 22 to the coupler 80 as a response signal f.

Next, the operation will be explained. When checking the presence or absence of a contact signal e from a monitored device, the center station continuously sends out a sine wave signal of a predetermined frequency unique to this terminal device to the CATV transmission line 10. This signal is input to the modulation section 30 from the transmission path 0 through the directional coupler 80.

The terminal address switch 20 outputs a transmitter control signal a according to its manual setting, and the transmitter 22 outputs a transmitter signal of a predetermined frequency in accordance with the control signal.

The modulating section 30 modulates the signal from the center using this transmission signal S, and outputs a variable gl signal C as a result. The passband of the bandpass filter 40 is set to pass such modulated signal C, and the modulated signal C is output to the rectifier 50. Note that the passband of the bandpass filter is the same for all terminal devices, and when the center station outputs a sine wave signal with a predetermined frequency unique to that terminal device, the modulated signal C is output from the filter 4o of that terminal device. be done. The rectifier 5o rectifies this modulation signal C and outputs a rectified signal d. As a result, the gate 60 is opened, and if the monitored device connected to this terminal device is outputting the contact signal e, the contact signal e is input to the switch 70. When the contact signal e is input, the switch 70 becomes conductive, and sends the outgoing signal as a response signal f to the transmission line 10 through the coupler 8o, and the center station connects the transmission line 1 to the transmission line 10.
The response signal f can be received and received through o. Note that when the center station polls another terminal device, it sends out a sine wave of a predetermined frequency unique to that terminal device.

Then, the terminal device sends a response signal to the center station by the same operation as the terminal described above.

As described above, the terminal device of the CATV monitoring system of the present invention has a simple configuration because it detects the contact signal of the monitored device and sends the response signal to the center station without using a CPU.

In the embodiment described above, the directional coupler 80, the terminal address switch 20, the transmitter 22, the modulator 30, the bandpass filter 40, and the rectifier constitute polling detection means, and the terminal address switch 2o and the transmitter 22 constitutes a response signal generating means, which includes a gate 60 and a switch 70.
, and the directional coupler 80 constitute response signal sending means.

〔Effect of the invention〕

As explained above, the present invention provides a polling detection means for receiving and detecting a polling signal sent from a center station from the CATV network and outputting a predetermined signal in a terminal device of a monitoring system using a CATV network. , a response signal generation means for generating a predetermined response signal, and a polling detection means output the predetermined signal, and when a contact signal is input from the monitored device, the response signal from the response signal ordering means is sent to the CATV network. and response signal sending means for sending the response signal to the center station through the communication terminal.

Therefore, according to the present invention, it is possible to realize a terminal device for a CATV monitoring system that does not use a CPU and therefore has a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a terminal device of a CATV monitoring system according to the present invention. 20... Terminal address switch 22... Transmission section 30... Modulation section 40... Band pass filter 50... Rectification section 60... Gate 70 ...Switch 80 ...Directional coupler

Claims (1)

[Claims] (1) In a terminal device of a monitoring system using a CATV network, polling detection means receives and detects a polling signal sent by a center station from the CATV network and outputs a predetermined signal, and generates a predetermined response signal. A response signal generation means and the polling detection means output the predetermined signal, and when a contact signal is input from the monitored device, the response signal from the response signal generation means is sent to the center station via the connected CATV network. 1. A terminal device for a CATV monitoring system, comprising: means for transmitting a response signal.