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Means of protection of the information |
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Tuesday, 30 May 2006 |
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Page 3 of 6
Television systems are widely applied to supervision over territory of protected object or over conditions indoors. Practically such systems have the common structure: some transmitting -chambers are connected to the central board where one or several monitors on which the image from any of transmitting chambers is possible to remove are established. At the common structure various systems differ types of used -chambers and the circuit of connection to the central board. Cable systems are used for protection of small objects temporarily taking place in territory (boxes with the equipment, special machines), and also the equipment inside premises. They will consist from lingering killed a cable representing the transmitter of radio waves, and the receiver located usually inside the protected perimeter. At hit of the infringer in a field created by a sensitive element, there is a change of an accepted signal and the alarm signal on the board of protection moves. It is possible to relate dependence on external factors to common faults of television and cable systems. For protection of the zone located between perimeter both its internal premises and representing, as a rule, windows and doors, it is used usually electromechanical contacts and magnetic gauges. Window panes and doors can be... Electromechanical vibrating signaling devices or electronic detectors. Action of such detectors is based on the analysis of the acoustic waves arising at gated of a barrier.
Spectral characteristics of such waves differ from a spectrum of the sounds accompanying impacts on a barrier or its vibration. Included in a design of the gauge logic circuits of the analysis of sound waves allow to distinguish reliably those cases when glass or a barrier similar to it really collapses, and to avoid occurrence of false alarms. Regulation of access in a premise is carried out with the help of well-known locks with a digital code a set. These devices are the most accessible and cheap. Their lacks in a small amount of probable combinations and absence of the signal system about attempts translations combinations and absence of the signal system about attempts translation combinations. Except for that there is an opportunity to learn a code, observing for actions of employees of establishment. Many complex systems with locks with management from microprocessors and micro the system recently have appeared. Prominent feature of such systems is the big number of probable combinations (up to 1 billion and more). There are also systems with remote control by the deputies. The transmitting device having the sizes no more a box radiates the certain combination of pulses of different length. The number of combinations depends on duration of pulses and from used carrying frequency. We shall consider some examples of such systems. In 1981 in the USA it has been declared manufacture of new system with programmed lock Data Key. The lock is connected to the microprocessor which analyzes the entrance information, compares it with reference and in case of concurrence submits the command on opening of the deputy by the carrier of the entrance information the key to the lock of the usual form, but the a little bit greater size is. On a surface of a key the information in volume up to 3000 bats which in case of need is erased can be rendered and another is replaced. For the premises demanding special protection, in the USA the special lock which is included in ramified system of physical protection, controlled by microprocessors and the central COMPUTER/62/is applied. The system functions as follows. The employee it is necessary for them to get in a protected premise contacts the central post of protection and requests the sanction to an input. If it is received, the central processor generates a casual combination which is transferred to the portable device, taking place at the employee. After the arrival to an entrance in a premise it once again calls with a post and informs on the readiness. The attendant submits a signal to the processor, and the chosen combination is transferred to the microprocessor which is taking place in the protected premise. Microprocessor transfers a code to the lock, and it is resulted in a status of readiness for 1 minutes. For this time entering the code from two figures should type, and in case of its concurrence with set the lock works. Any other actions entering (discrepancies of a code, attempt to type even a correct code, but after 1 minutes, etc.) Cause an alarm signal. Despite of the big flexibility of the newest equipment, all systems of such type (with use of locks) possess the common essential lack: keys can be transferred to other person, are lost or stolen, that causes only auxiliary role of similar systems in a complex of physical measures of protection. 3. The CONTROL of ACCESS OVER PROTECTED PREMISES of the Device and system of the identification of the person are applied basically in systems of controllable access in protected premises. Controllable access assumes restriction of the circle of persons, admitted in the certain protected zones, and the control over movement of persons inside such zones. This task is solved not only physical, but also equipment rooms or software. Only at combined use of all means probably effective decision of a problem. Physical means in systems of controllable access can use various principles of identification. In a foreign press pays the big attention to development of concepts of controllable access (project NICE, Canada, etc.).
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Security information 