Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point-to-point (P2P), point-to-multipoint (P2MP), or mesh wired or wireless links. Even though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that require additional security or ongoing monitoring (Videotelephony is seldom called "CCTV").
Surveillance of the public using CCTV is common in many areas around the world. Video surveillance has generated significant debate about balancing its use with individuals' right to privacy even when in public.
In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, especially if the environments observed are dangerous or inaccessible to humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, using digital video recorders (DVRs), provides recording for possibly many years, with a variety of quality and performance options and extra features (such as motion detection and email alerts). More recently, decentralized IP cameras, perhaps equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for completely stand-alone operation.
By one estimate, there will be approximately 1 billion surveillance cameras in use worldwide by 2021.[needs update] About 65% of these cameras are installed in Asia. The growth of CCTV has been slowing in recent years.[unreliable source?] The deployment of this technology has facilitated significant growth in state surveillance, a substantial rise in the methods of advanced social monitoring and control, and a host of crime prevention measures throughout the world.
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.
Some alarm systems serve a single purpose of burglary protection; combination systems provide fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complicated, multirole systems with computer monitoring and control. It may even include a two-way voice which allows communication between the panel and monitoring station.
Essex (/ˈɛsɪks/) is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south and Greater London to the south and south-west. The county town is Chelmsford, which remains the only city in the ceremonial county until Southend-on-Sea is formally accorded city status. For the purposes of government statistics, Essex is placed in the East of England region.
There are four definitions of the extent of Essex, the widest being the ancient county. Next largest is the former postal county, followed by the ceremonial county with the smallest being the administrative county – the area administered by the County Council, which excludes the two unitary authorities of Thurrock and Southend-on-Sea and the areas administered by the Greater London Authority.
The ceremonial county occupies the eastern part of what was, during the Early Middle Ages, the Anglo-Saxon Kingdom of Essex. As well as rural areas, the county also includes London Stansted Airport, the new towns of Basildon and Harlow, Lakeside Shopping Centre, the port of Tilbury and the borough of Southend-on-Sea.