ABOUT CCTV: Closed Circuit Television Systems (CCTV) and video monitoring and surveillance systems are becoming more common in offices, homes, city streets, banks and shopping malls. So where did these all-seeing monitoring, recording, access tracking security systems originate and why do we need them, and how does digital technology play a part in monitoring and surveillance?
CCTV actually dates way back to the 1950s but advancements in the 1970s gave rise to analog recording systems together with solid state cameras. There were no wireless systems back then so cameras were connected via cables to a multiplexer. The signals would then be fed to a recording device (usually a VCR) and/or monitor(s). A multiplexer is a device that allows the operator to cycle through each camera on the system one by one. There are several disadvantages with this type of system. The fact that a monitoring system is often centralized lends itself as being a single point of failure with the infrastructure. As all CCTV cameras were cabled in, if they needed to be moved often a new cable run was needed. Back in the control room magnetic media was the medium of which the images were stored and were susceptible to magnetic discharge or static electricity discharge. Also, for the system to run successfully a lot of human intervention is required for carrying out tasks such as physically changing the tapes, monitoring and recording the sessions etc.....
Second generation systems consisted of UTP enabled cameras which are IP addressable. Although these systems were able to run on the existing cable infrastructure they still may require expensive equipment such a tape libraries but the costs for the main monitoring station are reduced. However, there is still a risk of the main monitoring station to be the single point of failure. A multiplexer is still utilized to connect many cameras but this time using UTP cable with the popular RJ45 network connector, similar to the one that can be found in every modern computer today. Existing cameras that use coaxial (unbalanced) cable can have their signals converted to twisted pair (balanced) cable.
The latest generation of monitoring and recording systems are fully digital which utilize hardware such as Digital Video Recorders (DVRs) with IP based cameras and PC/monitors. These have many benefits over magnetic tape VCRs media libraries such as higher quality and definition and easily searchable and instant accessible recordings together with offering improved scalability and expandability. No longer do humans need to change tapes as backups can be automatically scheduled. More data can be recorded due to advanced digital compression techniques and storage is now moving to more reliable network based hardware such as Network Attached Storage (NAS) and SAN (Storage Area Networks) that can offer redundancy thus eliminating any single point of failure. One of the powerful benefits of digital CCTV systems is that the images can be viewed not only anywhere within an organization that has a UTP network connection, but anywhere in the world, via the internet. And images can be viewed simultaneously. IP addressable cameras can be placed anywhere on an existing IP network infrastructure thus reducing cost and eliminating the need for separate cabling systems.