Security system including a daughter station for monitoring an area and a remote parent station connected thereto
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a security system for preventing trespassing of an unauthorized person, vehicle, animal, or the like upon a specific region, and more particularly, to a security system which is more effectively operated in the case where the specific region or a site is monitored by a daughter or remote station of a so-called remote monitoring system. 
     2. Description of the Prior Art 
     The security system so far known is such a one as will, upon its sensor&#39;s sensing foreign matter, give an alarm at the locality by a siren or the like. With the development of the industrial television system, however, another system has also come to be used that will take, by means of a television camera, images of the state of affairs at the site and transmit the images taken to a monitoring site where the camera images are to be monitored by means of a monitoring television. 
     But there are some problems in the above described television monitoring system. That is, a system for transmitting such images needs a larger frequency band width, and if the monitoring site is remote from the site to be monitored by several hundred meters or more, special equipment and means for transmission becomes, in general, necessary. Therefore, the system becomes considerably expensive, or, in some cases, even becomes impracticable from the point of view of the means for transmission. 
     SUMMARY OF THE INVENTION 
     The present invention is contemplated to solve the above mentioned problems. Therefore, the principal object of the invention is to provided an inexpensive and economical security system which requires no special transmission path. 
     According to the security system of the present invention, the site to be monitored, which is under constant monitoring by a remote monitoring system, is provided with a sensor for sensing foreign matter such as man, animal, and vehicle, a television camera for taking the image of the state of affairs at the site to be monitored, and a video recorder for recording the image taken by the television camera, in which the sensor is adapted to output a signal when it senses foreign matter thereby to start the video recorder recording the image taken by the television camera as well as to notify, via the remote monitoring system, the monitoring site of the fact a trespass has occurred. 
     The observer at the monitoring site in the present invention will, when notified via the remote monitoring system of the trespass of foreign matter upon the site to be monitored, visit the site and find out what the foreign matter that made the trespass was by replaying and analyzing the contents of the record made by the video recorder by means of the monitoring television. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying single figure schematically shows a security system embodying the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The accompanying drawing is a block diagram showing a preferred embodiment of the present invention, wherein 10 denotes a site to be monitored where a daughter or remote station is installed and 20 denotes a monitoring site where a parent or master station is installed. In the site 10 to be monitored, 1 denotes a trespasser as foreign matter, 2 denotes a sensor for sensing the foreign matter within a predetermined region, 3 denotes a television camera for taking the scene of the state of affairs at the site to be monitored, 4 denotes a video recorder for recording the image of the scene taken by the television camera, 5 denotes a monitoring television for playing back the recorded contents by the video recorder 4 for analysis, and 6 denotes a daughter station unit of a remote monitoring apparatus. And, in the monitoring site 20 which is connected with the site to be monitored through a signal transmission path 7, 8 denotes a parent station unit of the remote monitoring apparatus and 9 denotes a monitoring panel. 
     In the security system structured as above, the daughter station unit 6 of the remote monitoring apparatus constantly converts conditions of various items at the site to be monitored (for example, opened or closed condition of a switch, actuated or unactuated condition of a fire sensor, etc.) which are sensed by a sensor or sensors (not shown) other than the sensor 2 into temporarily serialized codes and transmits the codes to the parent station unit 8 at the monitoring site through the signal transmission path 7. The parent station unit 8 arranges the received codes back to parallel data and displays the conditions of the respective items on the monitoring panel 9. 
     Now, if a trespasser appears on the site 10 to be monitored, the sensor 2 will sense this and report it to the daughter station unit 6 of the remote monitoring apparatus, and simultaneously starts up the video recorder 4 to record the image of the scene from the television camera 3. The daughter station unit 6 of the remote monitoring apparatus will transmit the sensed signal from the sensor 2 to the parent station unit 8 as one of the sensed items to be displayed on the monitoring panel 9. 
     The observer at the monitoring site 20 notified by the display on the monitoring panel 9 of the trespass of foreign matter upon the site 10 to be monitored will visit this site. After arrival at the site, even if the trespasser 1 has already disappeared from the site, the observer can find out what the trespasser was by playing back and analyzing the contents of the record made by the video recorder 4 by means of the monitoring television 5. 
     The security system of the invention is, as so far described, arranged so that the video recorder is started by the signal which is output by the sensor when the same senses a trespass of foreign matter upon the site to be monitored, whereby the image of the scene taken by the television camera is recorded and, at the same time, the trespass of the foreign matter is reported to the monitoring site. Thus, the present invention produces such effects that the security system needs no special transmission path and the same can be provided at low cost and economically.