Interfacing with Other Systems

From CCTV Information
Revision as of 12:09, 27 November 2010 by Gb003162 (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search


CCTV Systems are rarely used as the single means of security at any site. This is a wise approach, as CCTV cannot on its own provide total security for any location. There is very little point in having a system that enables intruders to be observed or miscreants identified if this does not actually prevent loss or damage to the property of the owner of the site. At the very minimum there must be good mechanical security with good quality doors, locks, fences and other barriers to physically prevent undesirables from gaining access to secure areas.

For insurance purposes, there must nearly always be some form of intruder detection and alarm system. With the growth and reduction in relative cost of telephone lines these intruder alarms are normally connected to some kind of central monitoring facility, called a central station, where responses to alarms are co-ordinated and from where the Police or other security agencies are summoned. Intruder alarm systems form the backbone of electronic security, from the smallest retail site to the largest industrial, commercial or governmental establishments.

A second mandatory electronic system present on sites is the fire alarm system. Fire alarm systems are installed for both insurance and building regulations purposes. Increasing use of electronics in the controls of these systems has meant that they have become more sophisticated and more reliable while at the same time offering many more features.

Having a site that is safe and secure outside business hours is vital. However, it is of little benefit during working hours, when access control to a building or site may be relaxed to enable the employer’s staff to come and go. Thieves or vandals can also come and go at will. It is for this reason that access control systems have started to become increasingly common. The simplest form of access control is a security guard checking the identification passes of those who are entering and leaving the site. In the highest security sites, this method is still used, due to the efficacy of human beings in recognising people and determining whether they should be allowed entry.

However, due to the cost of manned guarding and the dramatic reduction in the real cost of microprocessor based electronic systems over the last few years electronic access control systems are becoming more common. In these systems, the individuals who are permitted to enter various areas of a site carry some kind of token that is presented to an electronic reader. The control electronics then identifies this token and looks into electronic memory devices. If the individual’s token is valid for that entry point then an electric lock will be released for a short time to allow entry. Otherwise, access will be denied and an alarm message may be displayed on the system control terminal. The technologies available for the tokens are myriad; from simple magnetic stripe cards similar to bankers’ cards through to specialised high security cards, special keys, keypads, and even palm print readers.

On large sites there may be a very long length of fencing which can be a problem to protect at all times, within the limits that are available with manned guarding. It is, however, important to protect this perimeter in commercial and industrial sites to prevent theft and vandalism, and in governmental sites to meet these as well as terrorist and other threats. As with access control the best form of perimeter protection is manned guard posts. This is, however, very expensive and consequently this technique tends to be reserved for the highest security sites.

Due to this fact, various electronic devices have been developed to detect intruders crossing the perimeter. One group is seismic wires installed in the fence material, which detect cutting and climbing of the fence structure. Another group of seismic detectors are buried directly in the ground and detect the footsteps of intruders crossing the perimeter, the alarms being signalled by cable or radio link. Long range passive infrared detectors are also used. These sense the body heat of intruders crossing the perimeter. Finally, video motion detection as described in the previous chapter is used to sense intruders. In high security sites, these devices are often used in combination to minimise false alarms while maximising detection. On such sites, regular perimeter patrols give the highest level of security available.

More recently, the control of environmental and other systems around a site has been centralised into systems using personal computers. These Building Management Systems (BMS) control heating, lighting and air conditioning systems while also providing alarms on the failure of heating boilers, excessive sump water levels, etc.

The display of all these individual systems in front of an operator can be very confusing, requiring a high level of training for the staff to operate the systems individually. The level of work for the system operator when there are multiple alarms can also be excessive, as several different monitors and control panels must be used. A better solution is to integrate these different systems in to a central display station, such as a siteplan graphics system described in Chapter 12. This central point then gives the operator a single screen on which to observe and acknowledge any event in the system; using a computer mouse or touch screen the CCTV may be controlled at the same screen.

The purpose of this chapter is to describe the ways in which these other systems may be interfaced with the CCTV system to assemble an integrated security management system.

This article is an extract from chapter 19 of 'The Principles & Practice of CCTV' which is recognised as the benchmark for CCTV installation in the UK.